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Sample records for monoamine oxidase enzymes

  1. In vitro evaluation of Bacopa monniera extract and individual constituents on human recombinant monoamine oxidase enzymes.

    Science.gov (United States)

    Singh, Rajbir; Ramakrishna, Rachumallu; Bhateria, Manisha; Bhatta, Rabi Sankar

    2014-09-01

    Bacopa monniera is a traditional Ayurvedic medicinal plant that has been used worldwide for its nootropic action. Chemically standardized extract of B. monniera is now available as over the counter herbal remedy to enhance memory in children and adults. Considering the nootropic action of B. monniera, we evaluated the effect of clinically available B. monniera extract and six of B. monniera constituents (bacoside A3, bacopaside I, bacopaside II, bacosaponin C, bacosine, and bacoside A mixture) on recombinant human monoamine oxidase (MAO) enzymes. The effect of B. monniera extract and individual constituents on human recombinant MAO-A and MAO-B enzymes was evaluated using MAO-Glo(TM) assay kit (Promega Corporation, USA), following the instruction manual. IC50 and mode of inhibition were measured for MAO enzymes. Bacopaside I and bacoside A mixture inhibited the MAO-A and MAO-B enzymes. Bacopaside I exhibited mixed mode of inhibition with IC50 and Ki values of 17.08 ± 1.64 and 42.5 ± 3.53 µg/mL, respectively, for MAO-A enzyme. Bacopaside I is the major constituent of B. monniera, which inhibited the MAO-A enzyme selectively.

  2. Evidence that the methylation state of the monoamine oxidase A (MAOA) gene predicts brain activity of MAO A enzyme in healthy men

    National Research Council Canada - National Science Library

    Shumay, Elena; Logan, Jean; Volkow, Nora D; Fowler, Joanna S

    2012-01-01

    ...). PET brain imaging of monoamine oxidase A (MAO A)-an enzyme metabolizing neurotransmitters-revealed that MAO A levels vary widely between healthy men and this variability was not explained by the common MAOA genotype (VNTR genotype...

  3. The inhibition of monoamine oxidase by esomeprazole

    OpenAIRE

    2013-01-01

    Virtual screening of a library of drugs has suggested that esomeprazole, the S-enantiomer of omeprazole, may possess binding affinities for the active sites of the monoamine oxidase (MAO) A and B enzymes. Based on this finding, the current study examines the MAO inhibitory properties of esomeprazole. Using recombinant human MAO-A and MAO-B, IC50 values for the inhibition of these enzymes by esomeprazole were experimentally determined. To examine the reversibility of MAO inhibition by esomepra...

  4. Methadone, monoamine oxidase, and depression: opioid distribution and acute effects on enzyme activity

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, C.A.; Kreek, M.J.; Raghunath, J.; Arns, P.

    1983-09-01

    Narcotic withdrawal is often accompanied by an atypical depression which responds to resumption of narcotics. It was hypothesized that methadone might exert its antidepressant effects through monoamine oxidase (MAO) inhibition. The current study examined /sub 3/H-methadone distribution in rat brain and effects on regional MAO activity with acute doses (2.5 mg/kg) which approximate those found during chronic methadone maintenance in man. Limbic areas (amygdala, basomedial hypothalamus, caudate-putamen, hippocampus, preoptic nucleus), as well as pituitary and liver were assayed for MAO activity and methadone concentration. MAO activities did not differ significantly in acute methadone or saline-treated cage-mates at 1 or 24 hr. The concentrations of methadone at 1 hr ranged between 17 and 223 ng/100 mg wet wt tissue in the preoptic nucleus and pituitary, respectively. No significant correlation was found between change in MAO activity (MAO methadone/MAO saline) and methadone concentration in any region at 1 or 24 hr. This study does not support the hypothesis that methadone acts as an antidepressant through MAO inhibition, at least not following acute administration of this exogenous opioid.

  5. Fluorescent Probes for Analysis and Imaging of Monoamine Oxidase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dokyoung; Jun, Yong Woong; Ahn, Kyo Han [POSTECH, Pohang (Korea, Republic of)

    2014-05-15

    Monoamine oxidases catalyze the oxidative deamination of dietary amines and amine neurotransmitters, and assist in maintaining the homeostasis of the amine neurotransmitters in the brain. Dysfunctions of these enzymes can cause neurological and behavioral disorders including Parkinson's and Alzheimer's diseases. To understand their physiological roles, efficient assay methods for monoamine oxidases are essential. Reviewed in this Perspective are the recent progress in the development of fluorescent probes for monoamine oxidases and their applications to enzyme assays in cells and tissues. It is evident that still there is strong need for a fluorescent probe with desirable substrate selectivity and photophysical properties to challenge the much unsolved issues associated with the enzymes and the diseases.

  6. The Use of Multiscale Molecular Simulations in Understanding a Relationship between the Structure and Function of Biological Systems of the Brain: The Application to Monoamine Oxidase Enzymes.

    Science.gov (United States)

    Vianello, Robert; Domene, Carmen; Mavri, Janez

    2016-01-01

    HIGHLIGHTS Computational techniques provide accurate descriptions of the structure and dynamics of biological systems, contributing to their understanding at an atomic level.Classical MD simulations are a precious computational tool for the processes where no chemical reactions take place.QM calculations provide valuable information about the enzyme activity, being able to distinguish among several mechanistic pathways, provided a carefully selected cluster model of the enzyme is considered.Multiscale QM/MM simulation is the method of choice for the computational treatment of enzyme reactions offering quantitative agreement with experimentally determined reaction parameters.Molecular simulation provide insight into the mechanism of both the catalytic activity and inhibition of monoamine oxidases, thus aiding in the rational design of their inhibitors that are all employed and antidepressants and antiparkinsonian drugs. Aging society and therewith associated neurodegenerative and neuropsychiatric diseases, including depression, Alzheimer's disease, obsessive disorders, and Parkinson's disease, urgently require novel drug candidates. Targets include monoamine oxidases A and B (MAOs), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and various receptors and transporters. For rational drug design it is particularly important to combine experimental synthetic, kinetic, toxicological, and pharmacological information with structural and computational work. This paper describes the application of various modern computational biochemistry methods in order to improve the understanding of a relationship between the structure and function of large biological systems including ion channels, transporters, receptors, and metabolic enzymes. The methods covered stem from classical molecular dynamics simulations to understand the physical basis and the time evolution of the structures, to combined QM, and QM/MM approaches to probe the chemical mechanisms of enzymatic

  7. Chemotherapy-induced monoamine oxidase expression in prostate carcinoma functions as a cytoprotective resistance enzyme and associates with clinical outcomes.

    Directory of Open Access Journals (Sweden)

    Ryan R Gordon

    Full Text Available To identify molecular alterations in prostate cancers associating with relapse following neoadjuvant chemotherapy and radical prostatectomy patients with high-risk localized prostate cancer were enrolled into a phase I-II clinical trial of neoadjuvant chemotherapy with docetaxel and mitoxantrone followed by prostatectomy. Pre-treatment prostate tissue was acquired by needle biopsy and post-treatment tissue was acquired by prostatectomy. Prostate cancer gene expression measurements were determined in 31 patients who completed 4 cycles of neoadjuvant chemotherapy. We identified 141 genes with significant transcript level alterations following chemotherapy that associated with subsequent biochemical relapse. This group included the transcript encoding monoamine oxidase A (MAOA. In vitro, cytotoxic chemotherapy induced the expression of MAOA and elevated MAOA levels enhanced cell survival following docetaxel exposure. MAOA activity increased the levels of reactive oxygen species and increased the expression and nuclear translocation of HIF1α. The suppression of MAOA activity using the irreversible inhibitor clorgyline augmented the apoptotic responses induced by docetaxel. In summary, we determined that the expression of MAOA is induced by exposure to cytotoxic chemotherapy, increases HIF1α, and contributes to docetaxel resistance. As MAOA inhibitors have been approved for human use, regimens combining MAOA inhibitors with docetaxel may improve clinical outcomes.

  8. Leflunomide, a Reversible Monoamine Oxidase Inhibitor.

    Science.gov (United States)

    Petzer, Jacobus P; Petzer, Anél

    2016-01-01

    A screening study aimed at identifying inhibitors of the enzyme, monoamine oxidase (MAO), among clinically used drugs have indicated that the antirheumatic drug, leflunomide, is an inhibitor of both MAO isoforms. Leflunomide inhibits human MAO-A and MAO-B and exhibits IC50 values of 19.1 μM and 13.7 μM, respectively. The corresponding Ki values are 17.7 μM (MAO-A) and 10.1 μM (MAO-B). Dialyses of mixtures of the MAO enzymes and leflunomide show that inhibition of the MAOs by leflunomide is reversible. The principal metabolite of leflunomide, teriflunomide (A77 1726), in contrast is not an MAO inhibitor. This study concludes that, although leflunomide is only moderately potent as an MAO inhibitor, isoxazole derivatives may represent a general class of MAO inhibitors and this heterocycle may find application in MAO inhibitor design. In this respect, MAO inhibitors are used in the clinic for the treatment of depressive illness and Parkinson's disease, and are under investigation as therapy for certain types of cancer, Alzheimer's disease and age-related impairment of cardiac function.

  9. The use of multiscale molecular simulations in understanding a relationship between the structure and function of biological systems of the brain: the application to monoamine oxidase enzymes

    Directory of Open Access Journals (Sweden)

    Robert Vianello

    2016-07-01

    Full Text Available Aging society and therewith associated neurodegenerative and neuropsychiatric diseases, including depression, Alzheimer’s disease, obsessive disorders, and Parkinson’s disease, urgently require novel drug candidates. Targets include monoamine oxidases A and B (MAOs, acetylcholinesterase (AChE and butyrylcholinesterase (BChE, and various receptors and transporters. For rational drug design it is particularly important to combine experimental synthetic, kinetic, toxicological and pharmacological information with structural and computational work. This paper describes the application of various modern computational biochemistry methods in order to improve the understanding of a relationship between the structure and function of large biological systems including ion channels, transporters, receptors and metabolic enzymes. The methods covered stem from classical molecular dynamics simulations to understand the physical basis and the time evolution of the structures, to combined QM and QM/MM approaches to probe the chemical mechanisms of enzymatic activities and their inhibition. As an illustrative example, the later will focus on the monoamine oxidase family of enzymes, which catalyze the degradation of amine neurotransmitters in various parts of the brain, the imbalance of which is associated with the development and progression of a range of neurodegenerative disorders. Inhibitors that act mainly on MAO A are used in the treatment of depression, due to their ability to raise serotonin concentrations, while MAO B inhibitors decrease dopamine degradation and improve motor control in patients with Parkinson disease. Our results give strong support that both MAO isoforms, A and B, operate through the hydride transfer mechanism. Relevance of MAO catalyzed reactions and MAO inhibition in the context of neurodegeneration will be discussed.

  10. MONOAMINE OXIDASE: RADIOTRACER DEVELOPMENT AND HUMAN STUDIES.

    Energy Technology Data Exchange (ETDEWEB)

    FOWLER,J.S.; LOGAN,J.; VOLKOW,N.D.; WANG,G.J.; MACGREGOR,R.R.; DING,Y.S.

    2000-09-28

    PET is uniquely capable of providing information on biochemical transformations in the living human body. Although most of the studies of monoamine oxidase (MAO) have focused on measurements in the brain, the role of peripheral MAO as a phase 1 enzyme for the metabolism of drugs and xenobiotics is gaining attention (Strolin Benedetti and Tipton, 1998; Castagnoli et al., 1997.). MAO is well suited for this role because its concentration in organs such as kidneys, liver and digestive organs is high sometimes exceeding that in the brain. Knowledge of the distribution of the MAO subtypes within different organs and different cells is important in determining which substrates (and which drugs and xenobiotics) have access to which MAO subtypes. The highly variable subtype distribution with different species makes human studies even more important. In addition, the deleterious side effects of combining MAO inhibitors with other drugs and with foodstuffs makes it important to know the MAO inhibitory potency of different drugs both in the brain and in peripheral organs (Ulus et al., 2000). Clearly PET can play a role in answering these questions, in drug research and development and in discovering some of the factors which contribute to the highly variable MAO levels in different individuals.

  11. Process characterization of a monoamine oxidase

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Woodley, John

    2014-01-01

    .e, on biocatalyst development (e.g. improvement of expression levels), process development (e.g. improved oxygen supply, product removal strategies) or biocatalyst stabilization (e.g. through immobilization or directed evolution). This paper presents a systematic method to identify the bottleneck of a potential...... biocatalytic process using a monoamine oxidase to synthesise an intermediate in the manufacture of a drug for treating Hepatitis C (Telaprevir)....

  12. Imaging Monoamine Oxidase in the Human Brain

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, J. S.; Volkow, N. D.; Wang, G-J.; Logan, Jean

    1999-11-10

    Positron emission tomography (PET) studies mapping monoamine oxidase in the human brain have been used to measure the turnover rate for MAO B; to determine the minimum effective dose of a new MAO inhibitor drug lazabemide and to document MAO inhibition by cigarette smoke. These studies illustrate the power of PET and radiotracer chemistry to measure normal biochemical processes and to provide information on the effect of drug exposure on specific molecular targets.

  13. (/sup 11/C)clorgyline and (/sup 11/C)-L-deprenyl and their use in measuring functional monoamine oxidase activity in the brain using positron emission tomography

    Science.gov (United States)

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.

    1986-04-17

    This invention involves a new strategy for imaging the activity of the enzyme monoamine oxidase in the living body by using /sup 11/C-labeled enzyme inhibitors which bind irreversibly to an enzyme as a result of catalysis. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  14. Monoamine oxidase inhibitory activities of heterocyclic chalcones.

    Science.gov (United States)

    Minders, Corné; Petzer, Jacobus P; Petzer, Anél; Lourens, Anna C U

    2015-11-15

    Studies have shown that natural and synthetic chalcones (1,3-diphenyl-2-propen-1-ones) possess monoamine oxidase (MAO) inhibition activities. Of particular importance to the present study is a report that a series of furanochalcones acts as MAO-B selective inhibitors. Since the effect of heterocyclic substitution, other than furan (and more recently thiophene, piperidine and quinoline) on the MAO inhibitory properties of the chalcone scaffold remains unexplored, the aim of this study was to synthesise and evaluate further heterocyclic chalcone analogues as inhibitors of the human MAOs. For this purpose, heterocyclic chalcone analogues that incorporate pyrrole, 5-methylthiophene, 5-chlorothiophene and 6-methoxypyridine substitution were examined. Seven of the nine synthesised compounds exhibited IC50 values chalcones are reversible and competitive MAO inhibitors. 4h, however, may exhibit tight-binding to MAO-B, a property linked to its thiophene moiety. We conclude that high potency chalcones such as 4h represent suitable leads for the development of MAO-B inhibitors for the treatment of Parkinson's disease and possibly other neurodegenerative disorders.

  15. Brain Monoamine Oxidase-A Activity Predicts Trait Aggression

    Science.gov (United States)

    Alia-Klein, Nelly; Goldstein, Rita Z.; Kriplani, Aarti; Logan, Jean; Tomasi, Dardo; Williams, Benjamin; Telang, Frank; Shumay, Elena; Biegon, Anat; Craig, Ian W.; Henn, Fritz; Wang, Gene-Jack; Volkow, Nora D.; Fowler, Joanna S.

    2008-01-01

    The genetic deletion of monoamine oxidase A (MAO A, an enzyme which breaks down the monoamine neurotransmitters norepinephrine, serotonin and dopamine) produces aggressive phenotypes across species. Therefore, a common polymorphism in the MAO A gene (MAOA, MIM 309850, referred to as high or low based on transcription in non-neuronal cells) has been investigated in a number of externalizing behavioral and clinical phenotypes. These studies provide evidence linking the low MAOA genotype and violent behavior but only through interaction with severe environmental stressors during childhood. Here, we hypothesized that in healthy adult males the gene product of MAO A in the brain, rather than the gene per se, would be associated with regulating the concentration of brain amines involved in trait aggression. Brain MAO A activity was measured in-vivo in healthy non-smoking men with positron emission tomography using a radioligand specific for MAO A (clorgyline labeled with carbon 11). Trait aggression was measured with the Multidimensional Personality Questionnaire (MPQ). Here we report for the first time that brain MAO A correlates inversely with the MPQ trait measure of aggression (but not with other personality traits) such that the lower the MAO A activity in cortical and subcortical brain regions the higher the self-reported aggression (in both MAOA genotype groups) contributing to more than a third of the variability. Since trait aggression is a measure used to predict antisocial behavior, these results underscore the relevance of MAO A as a neurochemical substrate of aberrant aggression. PMID:18463263

  16. Ciproxifan, a histamine H3 receptor antagonist, reversibly inhibits monoamine oxidase A and B.

    Science.gov (United States)

    Hagenow, S; Stasiak, A; Ramsay, R R; Stark, H

    2017-01-13

    Ciproxifan is a well-investigated histamine H3 receptor (H3R) inverse agonist/antagonist, showing an exclusively high species-specific affinity at rodent compared to human H3R. It is well studied as reference compound for H3R in rodent models for neurological diseases connected with neurotransmitter dysregulation, e.g. attention deficit hyperactivity disorder or Alzheimer's disease. In a screening for potential monoamine oxidase A and B inhibition ciproxifan showed efficacy on both enzyme isoforms. Further characterization of ciproxifan revealed IC50 values in a micromolar concentration range for human and rat monoamine oxidases with slight preference for monoamine oxidase B in both species. The inhibition by ciproxifan was reversible for both human isoforms. Regarding inhibitory potency of ciproxifan on rat brain MAO, these findings should be considered, when using high doses in rat models for neurological diseases. As the H3R and monoamine oxidases are all capable of affecting neurotransmitter modulation in brain, we consider dual targeting ligands as interesting approach for treatment of neurological disorders. Since ciproxifan shows only moderate activity at human targets, further investigations in animals are not of primary interest. On the other hand, it may serve as starting point for the development of dual targeting ligands.

  17. Nitrogen heterocycles as potential monoamine oxidase inhibitors: Synthetic aspects

    Directory of Open Access Journals (Sweden)

    Pravin O. Patil

    2014-12-01

    Full Text Available The present review highlights the synthetic methods of monoamine oxidase inhibitors (MAO belonging to a group of nitrogen heterocycles such as pyrazoline, indole, xanthine, oxadiazole, benzimidazole, pyrrole, quinoxaline, thiazole and other related compounds (1990–2012. Moreover, it emphasizes salient findings related to chemical structures and the bioactivities of these heterocycles as MAO inhibitors. The aim of this review is to find out different methods for the synthesis of nitrogen containing heterocycles and their bioactivity related aspects as MAO inhibitors.

  18. A novel fluorogenic probe for monoamine oxidase assays

    Institute of Scientific and Technical Information of China (English)

    You You Lu; Yu Guang Wang; Bin Dai; Yi Qi Dai; Zhao Wang; Zheng Wei Fu; Qing Zhu

    2008-01-01

    Monoamine oxidase is flavoenzymes, widely distributed in mammals. It is well recognized that MAOs serve an important role in metabolism that they have close relationship with health .Along with the discoveries between MAOs and neurotic disease, more and more studies have been jumped in .In this paper, we design a new probe for assaying the activities of MAOs. The results showed that the probe [7-(3-aminopropoxy)coumarin] is simple, effective and sensitive for MAOB.

  19. The inhibition of monoamine oxidase by phenformin and pentamidine.

    Science.gov (United States)

    Barkhuizen, M; Petzer, A; Petzer, J P

    2014-09-01

    A computational study has suggested that phenformin, an oral hypoglycaemic drug, may bind to the active sites of the monoamine oxidase (MAO) A and B enzymes. The present study therefore investigates the MAO inhibitory properties of phenformin. Pentamidine, a structurally related diamidine compound, has previously been reported to be a MAO inhibitor and was included in this study as a reference compound. Using recombinant human MAO-A and MAO-B, this study finds that phenformin acts as a moderately potent MAO-A selective inhibitor with an IC50 value of 41 µM. Pentamidine, on the other hand, potently inhibits both MAO-A and MAO-B with IC50 values of 0.61 μM and 0.22 μM, respectively. An examination of the recoveries of the enzymatic activities after dilution and dialysis of the enzyme-inhibitor complexes shows that both compounds interact reversibly with the MAO enzymes. A kinetic analysis suggests that pentamidine acts as a competitive inhibitor with estimated Ki values of 0.41 μM and 0.22 μM for the inhibition of MAO-A and MAO-B, respectively. Phenformin also exhibited a competitive mode of MAO-A inhibition with an estimated Ki value of 65 µM. This study concludes that biguanide and amidine functional groups are most likely important structural features for the inhibition of the MAOs by phenformin and pentamidine, and compounds containing these and closely related functional groups should be considered as potential MAO inhibitors. Furthermore, the biguanide and amidine functional groups may act as useful moieties in the future design of MAO inhibitors.

  20. Quantitative distribution of monoamine oxidase A in brainstem monoamine nuclei is normal in major depression.

    Science.gov (United States)

    Ordway, G A; Farley, J T; Dilley, G E; Overholser, J C; Meltzer, H Y; Balraj, E K; Stockmeier, C A; Klimek, V

    1999-11-13

    An abnormal expression of noradrenergic proteins (e.g., tyrosine hydroxylase, norepinephrine transporters) in the locus coeruleus has recently been demonstrated in subjects with major depression and/or victims of suicide. Monoamine oxidase A (MAO-A) is a key enzyme in the catabolism of biogenic amines and is expressed in brain noradrenergic neurons. In this study, the binding of [3H]Ro41-1049 to MAO-A was measured by quantitative autoradiography at multiple levels along the rostral-caudal axis of the noradrenergic locus coeruleus from subjects with major depression and age- and postmortem interval-matched control subjects who were psychiatrically normal. [3H]Ro41-1049 binding to MAO-A was unevenly distributed along the axis of the locus coeruleus, paralleling an uneven number of neuromelanin-containing (noradrenergic) neurons throughout the nucleus. Accordingly, there was a significant correlation between the number of neuromelanin-containing neurons per section and the specific binding of [3H]Ro41-1049 at any particular level of the locus coeruleus in control subjects (r(2)=0.25; pdepression (r(2)=0.14; pdepression to psychiatrically normal control subjects. These findings demonstrate that the pathophysiology of major depression is not likely to involve abnormalities in MAO-A.

  1. Monoamine oxidase A is highly expressed in classical Hodgkin lymphoma.

    Science.gov (United States)

    Li, Pei Chuan; Siddiqi, Imran N; Mottok, Anja; Loo, Eric Y; Wu, Chieh Hsi; Cozen, Wendy; Steidl, Christian; Shih, Jean Chen

    2017-10-01

    Monoamine oxidase A (MAOA) is a mitochondrial enzyme that catalyzes oxidative deamination of neurotransmitters and dietary amines and produces H2 O2 . It facilitates the progression of gliomas and prostate cancer, but its expression and functional relevance have not been studied in lymphoma. Here, we evaluated MAOA in 427 cases of Hodgkin and non-Hodgkin lymphoma and in a spectrum of reactive lymphoid tissues by immunohistochemistry on formalin-fixed, paraffin-embedded specimens. MAOA was expressed by Hodgkin Reed-Sternberg (HRS) cells in the majority of classical Hodgkin lymphomas (cHLs) (181/241; 75%), with 34.8% showing strong expression. Weak MAOA was also noted in a minority of primary mediastinal large B-cell lymphomas (8/47; 17%) and in a mediastinal gray-zone lymphoma. In contrast, no MAOA was found in non-neoplastic lymphoid tissues, nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL; 0/8) or any other non-Hodgkin lymphomas studied (0/123). MAOA was more common in Epstein-Barr virus (EBV)-negative compared to EBV-positive cHL (p Hodgkin-lymphoma-derived cell lines did not. The MAOA inhibitor clorgyline reduced the growth of L1236 cells and U-HO1 cells, and shRNA knockdown of MAOA reduced the growth of L1236 cells. Conversely, ectopic overexpression of MAOA increased the growth of MAOA-negative HDLM2 cells. Combined treatment with clorgyline and ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) was more effective in reducing cell growth than either regimen alone. In summary, MAOA is highly expressed in cHL and may reflect the distinct biology of this lymphoma. Further studies on the potential utility of MAOA as a diagnostic marker and therapeutic target are warranted. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  2. 3-Coumaranone derivatives as inhibitors of monoamine oxidase

    Directory of Open Access Journals (Sweden)

    Van Dyk AS

    2015-10-01

    Full Text Available Adriaan S Van Dyk,1,2 Jacobus P Petzer,1,2 Anél Petzer,1 Lesetja J Legoabe1 1Centre of Excellence for Pharmaceutical Sciences, 2Pharmaceutical Chemistry, School of Pharmacy, North-West University, Potchefstroom, South Africa Abstract: The present study examines the monoamine oxidase (MAO inhibitory properties of a series of 20 3-coumaranone [benzofuran-3(2H-one] derivatives. The 3-coumaranone derivatives are structurally related to series of α-tetralone and 1-indanone derivatives, which have recently been shown to potently inhibit MAO, with selectivity for MAO-B (in preference to the MAO-A isoform. 3-Coumaranones are similarly found to selectively inhibit human MAO-B with half-maximal inhibitory concentration (IC50 values of 0.004–1.05 µM. Nine compounds exhibited IC50<0.05 µM for the inhibition of MAO-B. For the inhibition of human MAO-A, IC50 values ranged from 0.586 to >100 µM, with only one compound possessing an IC50<1 µM. For selected 3-coumaranone derivatives, it is established that MAO-A and MAO-B inhibition are reversible since dialysis of enzyme–inhibitor mixtures almost completely restores enzyme activity. On the basis of the selectivity profiles and potent action, it may be concluded that the 3-coumaranone derivatives are suitable leads for the development of selective MAO-B inhibitors as potential treatment for disorders such as Parkinson’s disease and Alzheimer’s disease. Keywords: benzofuran-3(2H-one, MAO, inhibition, reversible, competitive, Parkinson’s disease 

  3. 2-acetylphenol analogs as potent reversible monoamine oxidase inhibitors

    Directory of Open Access Journals (Sweden)

    Legoabe LJ

    2015-07-01

    Full Text Available Lesetja J Legoabe,1 Anél Petzer,1 Jacobus P Petzer1,21Centre of Excellence for Pharmaceutical Sciences, 2Department of Pharmaceutical Chemistry, School of Pharmacy, North-West University, Potchefstroom, South AfricaAbstract: Based on a previous report that substituted 2-acetylphenols may be promising leads for the design of novel monoamine oxidase (MAO inhibitors, a series of C5-substituted 2-acetylphenol analogs (15 and related compounds (two were synthesized and evaluated as inhibitors of human MAO-A and MAO-B. Generally, the study compounds exhibited inhibitory activities against both MAO-A and MAO-B, with selectivity for the B isoform. Among the compounds evaluated, seven compounds exhibited IC50 values <0.01 µM for MAO-B inhibition, with the most selective compound being 17,000-fold selective for MAO-B over the MAO-A isoform. Analyses of the structure–activity relationships for MAO inhibition show that substitution on the C5 position of the 2-acetylphenol moiety is a requirement for MAO-B inhibition, and the benzyloxy substituent is particularly favorable in this regard. This study concludes that C5-substituted 2-acetylphenol analogs are potent and selective MAO-B inhibitors, appropriate for the design of therapies for neurodegenerative disorders such as Parkinson’s disease.Keywords: monoamine oxidase, MAO, inhibition, 2-acetylphenol, structure–activity relationship

  4. [Substrate-inhibitory analysis of monoamine oxidase from hepatopancreas of the octopus Bathypolypus arcticus].

    Science.gov (United States)

    Basova, I N; Iagodina, O V

    2012-01-01

    Study of the substrate-inhibitory specificity of mitochondrial monoamine oxidase (MAO) of hepatopancreas of the octopus Bathypolypus arcticus revealed distinctive peculiarities of catalytic properties of this enzyme. The studied enzyme, on one hand, like the classic MAO of homoiothermal animals, is able to deaminate tyramine, serotonin, benzylamine, tryptamine, beta-phenylethylamine, while, on the other hand, deaminates histamine and does not deaminate putrescine--classic substrates of diamine oxidase (DAO). Results of the substrate-inhibitory analysis with use of chlorgiline and deprenyl are indirect proofs of the existence in the octopus hepatopancreas of one molecular MAO form. Semicarbazide and pyronine G turned out to be weak irreversible inhibitors, four derivatives of acridine--irreversible inhibitors of the intermediate effectiveness with respect to the octopus hepatopancreas MAO; specificity of action of inhibitors at deamination of different substrates was equal.

  5. Monoamine oxidase B layer-by-layer film fabrication and characterization toward dopamine detection

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, Celina Massumi; Pereira, Tamyris Paschoal [Universidade Federal de São Carlos, UFSCar, CCTS, Sorocaba, São Paulo (Brazil); Mascagni, Daniela Branco Tavares [Universidade Estadual de São Paulo — UNESP, Sorocaba, São Paulo (Brazil); Leite de Moraes, Marli [Universidade Federal de São Paulo, Unifesp, São José dos Campos, São Paulo (Brazil); Ferreira, Marystela, E-mail: marystela@ufscar.br [Universidade Federal de São Carlos, UFSCar, CCTS, Sorocaba, São Paulo (Brazil)

    2016-01-01

    In this work nanostructured film composites of the monoamine oxidase B (MAO-B) enzyme, free or encapsulated in liposomes, were fabricated by the layer-by-layer (LbL) self-assembly technique, employing polyethylene imine (PEI) as polycation. Initially, the MAO-B enzyme was incorporated into liposomes in order to preserve its enzymatic structure ensuring their activity and catalytic stability. The LbL film growth was monitored by surface plasmon resonance (SPR) by gold resonance angle shift analysis after each bilayer deposition. Subsequently, the films were applied as amperometric biosensors for dopamine detection using Prussian Blue (PB) as the electron mediator. The biosensor fabricated by MAO-B incorporated into liposomes composed of DPPG:POPG in the ratio (1:4) (w/w) showed the best performance with a sensitivity of 0.86 (μA cm{sup −2})/(mmol L{sup −1}) and a detection limit of 0.33 mmol L{sup −1}. - Highlights: • Monoamine oxidase B incorporation in liposomes was proposed to preserve the enzyme. • Layer-by-layer films composed of MAO-B (free and in liposomes) were fabricated. • Amperometric response using ITO/Prussian Blue covered with the MAO-B films was studied. • Sensitivity, limit of detection and apparent Michaelis–Menten constant were compared.

  6. Low platelet monoamine oxidase activity in pathological gambling

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco, J.L. [Department of Psychiatry, Centro de Salud Mental, Parla Madrid (Spain); Saiz-Ruiz, J. [Department of Psychiatry and Haematology, Hospital Ramon y Cajal, Madrid (Spain); Hollander, E. [Department of Psychiatry, Mount Sinai School of Medicine, Queens Hospital Center, New York (United States); Cesar, J. [Department of Haematology, Hospital Ramon y Cajal, Madrid (Spain); Lopez-Ibor, J.J. Jr. [Department of Psychiatry, Hospital San Carlos, Complutense University, Madrid (Spain)

    1994-12-01

    Decreased platelet monoamine oxidase (MAO) activity has been reported in association with sensation-seeking personality type and in some mental disorders associated with a lack of impulse control. Pathological gambling itself has been related with both sensation-seeking and reduced impulse control. Platelet MAO activity was investigated in 15 DSM-III-R pathological gamblers from our outpatient clinic. Gamblers had a significantly lower platelet MAO activity than a group of 25 healthy controls. The range of MAO levels in gamblers was also significantly shorter than in controls. In controls, platelet MAO levels showed the previously described negative correlations with sensation-seeking scores but not in gamblers. The findings are consistent with previous studies showing an association of low platelet MAO activity with impulse control disorders and raise some interesting therapeutic alternatives for pathological gambling. (au) (40 refs.).

  7. On-line radiochemical assay for monoamine oxidase utilizing high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Nissinen, E.; Linko-Loeppoenen SMae; Maennistoe P4

    1984-12-01

    A fast and sensitive assay for the determination of monoamine oxidase activity was developed. The method is based on the separation and quantitation of /sup 14/C-labeled assay products by high-performance liquid chromatography, which is interfaced directly into a flow-through radioactivity detector. This allows on-line quantitation of the radioactive compounds with picomole sensitivity. The method makes possible the complete separation and detection of the deaminated products of monoamine oxidase A and B substrates benzylamine and 5-hydroxytryptamine, respectively. This assay has been applied to the measurement of monoamine oxidase A and B activities in rat brain.

  8. Monoamine oxidase B layer-by-layer film fabrication and characterization toward dopamine detection.

    Science.gov (United States)

    Miyazaki, Celina Massumi; Pereira, Tamyris Paschoal; Mascagni, Daniela Branco Tavares; de Moraes, Marli Leite; Ferreira, Marystela

    2016-01-01

    In this work nanostructured film composites of the monoamine oxidase B (MAO-B) enzyme, free or encapsulated in liposomes, were fabricated by the layer-by-layer (LbL) self-assembly technique, employing polyethylene imine (PEI) as polycation. Initially, the MAO-B enzyme was incorporated into liposomes in order to preserve its enzymatic structure ensuring their activity and catalytic stability. The LbL film growth was monitored by surface plasmon resonance (SPR) by gold resonance angle shift analysis after each bilayer deposition. Subsequently, the films were applied as amperometric biosensors for dopamine detection using Prussian Blue (PB) as the electron mediator. The biosensor fabricated by MAO-B incorporated into liposomes composed of DPPG:POPG in the ratio (1:4) (w/w) showed the best performance with a sensitivity of 0.86 (μA cm(-2))/(mmol L(-1)) and a detection limit of 0.33 mmol L(-1).

  9. Selected chromone derivatives as inhibitors of monoamine oxidase.

    Science.gov (United States)

    Legoabe, Lesetja J; Petzer, Anél; Petzer, Jacobus P

    2012-09-01

    A previous study has shown that a series of C6-benzyloxy substituted chromones exhibit high binding affinities for human monoamine oxidase (MAO) B. In an attempt to discover additional chromones with potent and selective MAO-B inhibitory potencies and to further examine the structure-activity relationships of MAO-B inhibition by chromones, the series was expanded with homologues containing polar functional groups on C3 of the chromone ring. The results demonstrate that 6-[(3-bromobenzyl)oxy]chromones containing acidic and aldehydic functional groups on C3 act as potent reversible MAO-B inhibitors with IC(50) values of 2.8 and 3.7 nM, respectively. Interestingly, a 2-hydroxy-2,3-dihydro-1-benzopyran-4-one derivative as well as open-ring 2-acetylphenol analogues of the chromones also were potent MAO-B inhibitors with IC(50) values ranging from 4 to 11 nM. Chromone derivatives containing the benzyloxy substituent on C5 of the chromone ring, however, exhibit MAO-B inhibition potencies that are several orders of magnitude weaker. High potency inhibitors of MAO-B may find application in the therapy of neurodegenerative disorders such as Parkinson's disease. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Selected C7-substituted chromone derivatives as monoamine oxidase inhibitors.

    Science.gov (United States)

    Legoabe, Lesetja J; Petzer, Anél; Petzer, Jacobus P

    2012-12-01

    A series of C7-substituted chromone (1-benzopyran-4-one) derivatives were synthesized and evaluated as inhibitors of recombinant human monoamine oxidase (MAO) A and B. The chromones are structurally related to a series of C7-functionalized coumarin (1-benzopyran-2-one) derivatives which has been reported to act as potent MAO inhibitors. The results of the current study document that the chromones are highly potent reversible inhibitors of MAO-B with IC(50) values ranging from 0.008 to 0.370 μM. While the chromone derivatives also exhibit affinities for MAO-A, with IC(50) values ranging from 0.495 to 8.03 μM, they are selective for the MAO-B isoform. Structure-activity relationships (SAR) show that 7-benzyloxy substitution of chromone is suitable for MAO-B inhibition with tolerance for a variety of substituents and substitution patterns on the benzyloxy ring. It may be concluded that 7-benzyloxychromones are appropriate lead compounds for the design of reversible and selective MAO-B inhibitors. With the aid of modeling studies, potential binding orientations and interactions of selected chromone derivatives in the MAO-A and -B active sites are examined. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Adipogenesis-related increase of semicarbazide-sensitive amine oxidase and monoamine oxidase in human adipocytes.

    Science.gov (United States)

    Bour, Sandy; Daviaud, Danièle; Gres, Sandra; Lefort, Corinne; Prévot, Danielle; Zorzano, Antonio; Wabitsch, Martin; Saulnier-Blache, Jean-Sébastien; Valet, Philippe; Carpéné, Christian

    2007-08-01

    A strong induction of semicarbazide-sensitive amine oxidase (SSAO) has previously been reported during murine preadipocyte lineage differentiation but it remains unknown whether this emergence also occurs during adipogenesis in man. Our aim was to compare SSAO and monoamine oxidase (MAO) expression during in vitro differentiation of human preadipocytes and in adipose and stroma-vascular fractions of human fat depots. A human preadipocyte cell strain from a patient with Simpson-Golabi-Behmel syndrome was first used to follow amine oxidase expression during in vitro differentiation. Then, human preadipocytes isolated from subcutaneous adipose tissues were cultured under conditions promoting ex vivo adipose differentiation and tested for MAO and SSAO expression. Lastly, human adipose tissue was separated into mature adipocyte and stroma-vascular fractions for analyses of MAO and SSAO at mRNA, protein and activity levels. Both SSAO and MAO were increased from undifferentiated preadipocytes to lipid-laden cells in all the models: 3T3-F442A and 3T3-L1 murine lineages, human SGBS cell strain or human preadipocytes in primary culture. In human subcutaneous adipose tissue, the adipocyte-enriched fraction exhibited seven-fold higher amine oxidase activity and contained three- to seven-fold higher levels of mRNAs encoded by MAO-A, MAO-B, AOC3 and AOC2 genes than the stroma-vascular fraction. MAO-A and AOC3 genes accounted for the majority of their respective MAO and SSAO activities in human adipose tissue. Most of the SSAO and MAO found in adipose tissue originated from mature adipocytes. Although the mechanism and role of adipogenesis-related increase in amine oxidase expression remain to be established, the resulting elevated levels of amine oxidase activities found in human adipocytes may be of potential interest for therapeutic intervention in obesity.

  12. A survey of prescribing practices for monoamine oxidase inhibitors.

    Science.gov (United States)

    Balon, R; Mufti, R; Arfken, C L

    1999-07-01

    A survey examined prescribing practices for monoamine oxidase inhibitors (MAOIs) and explored reasons for the widely noted decline in their use. A one-page questionnaire was sent in 1997 to 1,129 members of the Michigan Psychiatric Association. A total of 717 responses were received, for a response rate of 64 percent. Only data from the 573 psychiatrists who were currently practicing were used. Twelve percent of the respondents never prescribed MAOIs, 27 percent had not prescribed them for at least three years, and 17 percent had prescribed them from one to three years ago. Thirty percent of the respondents had prescribed an MAOI within the past three months, and 14 percent between three and 12 months ago. The most frequent reasons for not prescribing the drugs were side effects and interactions with other medications (46 percent), preference for other medications (30 percent), and dietary restrictions necessary for patients taking MAOIs (19 percent). Ninety-two percent of respondents believed that MAOIs were useful for atypical depression, 64 percent for major depression, 54 percent for melancholic depression, 56 percent for panic disorder, 44 percent for social phobia, 27 percent for dysthymia, 12 percent for obsessive-compulsive disorder, and 19 percent for posttraumatic stress disorder. However, only 2 percent said they would use MAOIs as their first-line treatment in atypical depression, and only 3 percent would use them a first-line treatment in social phobia. The results document the commonly held view that practicing psychiatrists believe MAOIs are efficacious but use them infrequently, primarily due to concerns about side effects and drug interactions.

  13. The mitochondrial monoamine oxidase-aldehyde dehydrogenase pathway: a potential site of action of daidzin.

    Science.gov (United States)

    Rooke, N; Li, D J; Li, J; Keung, W M

    2000-11-02

    Recent studies showed that daidzin suppresses ethanol intake in ethanol-preferring laboratory animals. In vitro, it potently and selectively inhibits the mitochondrial aldehyde dehydrogenase (ALDH-2). Further, it inhibits the conversion of monoamines such as serotonin (5-HT) and dopamine (DA) into their respective acid metabolites, 5-hydroxyindole-3-acetic acid (5-HIAA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in isolated hamster or rat liver mitochondria. Studies on the suppression of ethanol intake and inhibition of 5-HIAA (or DOPAC) formation by six structural analogues of daidzin suggested a potential link between these two activities. This, together with the finding that daidzin does not affect the rates of mitochondria-catalyzed oxidative deamination of these monoamines, raised the possibility that the ethanol intake-suppressive (antidipsotropic) action of daidzin is not mediated by the monoamines but rather by their reactive biogenic aldehyde intermediates such as 5-hydroxyindole-3-acetaldehyde (5-HIAL) and/or 3,4-dihydroxyphenylacetaldehyde (DOPAL) which accumulate in the presence of daidzin. To further evaluate this possibility, we synthesized more structural analogues of daidzin and tested and compared their antidipsotropic activities in Syrian golden hamsters with their effects on monoamine metabolism in isolated hamster liver mitochondria using 5-HT as the substrate. Effects of daidzin and its structural analogues on the activities of monoamine oxidase (MAO) and ALDH-2, the key enzymes involved in 5-HT metabolism in the mitochondria, were also examined. Results from these studies reveal a positive correlation between the antidipsotropic activities of these analogues and their abilities to increase 5-HIAL accumulation during 5-HT metabolism in isolated hamster liver mitochondria. Daidzin analogues that potently inhibit ALDH-2 but have no or little effect on MAO are most antidipsotropic, whereas those that also potently inhibit MAO exhibit little, if

  14. Potential of Natural Products of Herbal Origin as Monoamine Oxidase Inhibitors.

    Science.gov (United States)

    Orhan, Ilkay Erdogan

    2016-01-01

    Monoamine oxidase (MAO, E.C. 1.4.3.4) is a flavin-adenine type of enzyme with two isoforms referred to MAO-A and MAO-B that function for oxidation of monoamines. While MAO-A inhibitors are effective as antidepressant and anxiolytic drugs (e.g. chlorgyline, moclobemide, and lazabemide), inhibitors of MAO-B (e.g. Ldeprenyl, pargyline, and rasagiline) are used against neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. Considering the need for novel MAO inhibitors due to side effects of the current ones, natural products have become attractive targets for researchers. Up till now, many studies revealed strong MAO inhibitory activity of flavonoid, xanthone, alkaloid, and coumarin derivatives from herbal sources, which also become good models for the synthetic MAO inhibitors. For this purpose, the present review focuses on examples of in vitro and in vivo MAO-inhibiting natural compounds of plant origin from a wide variety of chemical classes isolated mainly between 2000 - 2015.

  15. Development of new radiopharmaceuticals for imaging monoamine oxidase B

    Energy Technology Data Exchange (ETDEWEB)

    Vasdev, Neil, E-mail: neil.vasdev@utoronto.ca; Sadovski, Oleg; Moran, Matthew D.; Parkes, Jun; Meyer, Jeffrey H.; Houle, Sylvain; Wilson, Alan A.

    2011-10-15

    Introduction: Imaging monoamine oxidase B (MAO-B) in the central nervous system with PET is an important goal for psychiatric studies. We here report an improved and automated radiosynthesis of N-(6-[{sup 18}F]-fluorohexyl)-N-methylpropargylamine ([{sup 18}F]FHMP; [{sup 18}F]-1), as well as the radiosynthesis of two new promising candidates for imaging cerebral MAO-B, namely, carbon-11-labeled 3-(4-[{sup 11}C]-methoxyphenyl)-6-methyl-2H-1-benzopyran-2-one ([{sup 11}C]-2) and N-((1H-pyrrol-2-yl)methyl)-N-[{sup 11}C]-methyl-1-phenylmethanamine ([{sup 11}C]-3). Methods: Fluorine-18-labeled 1 was prepared via a tosyloxy precursor in 29%{+-}5% uncorrected radiochemical yield, relative to [{sup 18}F]-fluoride. Both carbon-11-labeled compounds were prepared with [{sup 11}C]CH{sub 3}I using the 'LOOP' method in 11% and 18% uncorrected radiochemical yields, respectively, relative to starting [{sup 11}C]CO{sub 2}. All radiotracers had specific activities >37 GBq/{mu}mol and were >98% radiochemically pure at end of synthesis (<40 min). All radiotracers were evaluated by ex vivo biodistribution studies in conscious rodents. Results: A major radioactive metabolite in the rodent brain was observed following administration of [{sup 18}F]-1. While [{sup 11}C]-2 had moderate brain penetration and good clearance from normal brain tissue, distribution of radioactivity in brain was indicative of free and nonspecific binding. Good brain uptake was observed with [{sup 11}C]-3 (0.8%-1.4% injected dose per gram at 5 min postinjection), binding appeared to be reversible and distribution conformed with regional distribution of MAO-B in the rat brain. Preinjection of 3 or L-deprenyl showed a modest reduction (up to 25%) of brain activity. Conclusion: Carbon-11-labeled 3 was found to have the most favorable properties of the radiotracers evaluated; however, the signal-to-noise ratio was too low to warrant further in vivo imaging studies. Alternative radiotracers for imaging MAO

  16. Iododerivative of pargyline: A potential tracer for the exploration of monoamine oxidase sites by SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Lena, Isabelle; Ombetta, Jean-Edouard; Chalon, Sylvie; Dognon, Anne-Marie; Baulieu, Jean-Louis; Frangin, Yves; Garreau, Lucette; Besnard, Jean-Claude; Guilloteau, Denis

    1995-08-01

    Monoamine oxidases are important in the regulation of monoaminergic neurotransmission. An increase in monoamine oxidase B (MAO B) has been observed in some neurodegenerative diseases, and therefore quantification of cerebral MAO B activity by SPECT would be useful for the diagnosis and therapeutic follow-up of these disorders. We have developed an iodinated derivative of pargyline, a selective inhibitor of MAO B, in order to explore this enzyme by SPECT. Stable bromo and iodo derivatives of pargyline were synthesized and chemically characterized. The radioiodinated ligand [{sup 125}I]-2-iodopargyline was obtained with high specific activity from the bromo precursor by nucleophilic exchange. Affinity and selectivity of 2-iodopargyline were tested in vitro. Biodistribution study of [{sup 125}I]-2-iodopargyline was performed in rats. Radioiodinated ligand were obtained in a no-carrier-added form. 2-iodopargyline has a higher in vitro affinity for MAO B than pargyline. However, the in vitro selectivity for MAO B was better for pargyline than for 2-iodopargyline. Ex vivo autoradiographic studies and in vivo saturation studies with selective inhibitors of MAO showed that the cerebral biodistribution of [{sup 125}I]-2-iodopargyline in the rat is consistent with high level binding to MAO B sites in the pineal gland and in the thalamus. In conclusion, 2-iodopargyline preferentially binds in vivo to MAO B sites with high affinity. However, its selectivity for MAO B in rats is not very high, whereas this ligand binds to a lesser extent to MAO A. It will be then of great value to evaluate the specificity of 2-iodopargyline in humans. This new ligand labeled with {sup 123}I should therefore be a suitable tool for SPECT exploration of MAO B in the human brain.

  17. Inhibition of monoamine oxidase by furazolidone in the chicken and the influence of the alimentary flora thereon.

    OpenAIRE

    Ali, B. H.; Bartlet, A. L.

    1980-01-01

    1 The addition of furazolidone to the feed at the therapeutic level (0.04% w/w, 10 days) inhibited monoamine oxidase (MAO) activity by 47 to 72% in chicken duodenal mucosa, heart and brain, but in the liver the enzyme activity was unaffected by the treatment. 2 Furazolidone (200 mg/kg) administered by crop tube inhibited MAO activities in duodenal mucosa, liver, heart and brain. 3 Furazolidone (200 mg/kg) injected intramuscularly did not inhibit MAO activity in the chicken. 4 Pretreatment of ...

  18. Reducing the Burden of Difficult-to-Treat Major Depressive Disorder: Revisiting Monoamine Oxidase Inhibitor Therapy

    OpenAIRE

    Culpepper, Larry

    2013-01-01

    Objective: Difficult-to-treat depression (eg, depression with atypical or anxious symptoms, treatment-resistant depression, or depression with frequent recurrence) is a challenging real-world health issue. This critical review of the literature focuses on monoamine oxidase inhibitor (MAOI) therapy and difficult-to-treat forms of depression.

  19. Monoamine Oxidase a Promoter Gene Associated with Problem Behavior in Adults with Intellectual/Developmental Disabilities

    Science.gov (United States)

    May, Michael E.; Srour, Ali; Hedges, Lora K.; Lightfoot, David A.; Phillips, John A., III; Blakely, Randy D.; Kennedy, Craig H.

    2009-01-01

    A functional polymorphism in the promoter of the gene encoding monoamine oxidase A has been associated with problem behavior in various populations. We examined the association of MAOA alleles in adult males with intellectual/developmental disabilities with and without established histories of problem behavior. These data were compared with a…

  20. Kinetics of Inhibition of Monoamine Oxidase Using Cymbopogon martinii (Roxb.) Wats.: A Potential Antidepressant Herbal Ingredient with Antioxidant Activity.

    Science.gov (United States)

    Gacche, R N; Shaikh, R U; Chapole, S M; Jadhav, A D; Jadhav, S G

    2011-07-01

    The study was designed to evaluate the antioxidant activity and effect of Cymbopogon martinii (Roxb.) Wats. (Poaceae) leaves on the activity of monoamine oxidase and kinetics of enzyme inhibition. Ethanol extract of C. martinii and rat brain mitochondrial monoamine oxidase preparation ware used to study the kinetics of enzyme inhibition using double reciprocal Lineweaver-Burk plot. The DPPH was used as a source of free radical to evaluate antioxidant potential. It is observed that, the ethanolic extract of C. martinii inhibits the monoamine oxidase activity with competitive mode of inhibition. The V(max) (0.01 mM/min) remained constant while, K(m) varied from 21.00 ± 1.1, 43.33 ± 1.5 and 83.33 ± 1.4 mM for 100-500 μg/ml concentration of C. martinii. The K(i) values were calculated to be 90.00 ± 0.87, 75.00 ± 0.69, 68.18 ± 0.68 μg for 100-500 μg/ml concentration of C. martini. It also shows a significant DPPH (1,1-diphenyl-2-picryl hydrazine) radical scavenging (IC(50) = 0.34 ± 0.05 mg/ml) and reducing activity (IC(50) = 0.70 ± 0.22 mg/ml). The C. martini can be considered as a possible source of MAO inhibitor used in the treatment of depression and other neurological disorders.

  1. High-throughput screening for monoamine oxidase-A and monoamine oxidase-B inhibitors using one-step fluorescence assay

    Institute of Scientific and Technical Information of China (English)

    Hong-mei GUANG; Guan-hua DU

    2006-01-01

    Aim: To develop high-throughput screening (HTS) assays for monoamine oxidase (MAO)-A and MAO-B inhibitors. Methods: A fluorescence probe based method measuring MAO-A and MAO-B activity was established and optimized, with its sensitivity, stability and specificity evaluated. Reaction conditions including enzyme sources, substrate concentrations, incubation volume and reaction time in 384-well format were optimized to achieve sensitive and low consumptive goal. Results: In optimized conditions, dynamic parameters of MAO-A and MAO-B were obtained. The Km value of serotonin to MAO-A was 1.66 μmol/L, while that of benzylamine to MAO-B was 0.80 umol/L. The IC50 value of clorgyline to MAO-A was 2.99 nmol/L, and that of deprenyl to MAO-B was 7.04 nmol/L, matching those obtained from traditional spectrometric assays. Among tested samples, one compound exerted an inhibitory effect on MAO-A activity with IC50 as 0.36 μmol/L, and three compounds had an inhibitory effect on MAO-B activity with IC50 as 0.13,0.19, and 0.13 μmol/L. The Z' factor was 0.71±0.03 and 0.75±0.03 in MAO-A-inhibitor and MAO-B-inhibitor HTS system, respectively. Conclusion: The established assays can be well applied to MAO-A and MAO-B inhibitor screening with high quality, precision and reproducibility.

  2. Relationship of monoamine oxidase A binding to adaptive and maladaptive personality traits.

    Science.gov (United States)

    Soliman, A; Bagby, R M; Wilson, A A; Miler, L; Clark, M; Rusjan, P; Sacher, J; Houle, S; Meyer, J H

    2011-05-01

    Monoamine oxidase A (MAOA) is an important enzyme that metabolizes monoamines such as serotonin, norepinephrine and dopamine in the brain. In prefrontal cortex, low MAOA binding is associated with aggression and high binding is associated with major depressive disorder (MDD) and also risk for recurrence of depressive episodes. In rodent models, low MAOA levels are associated with increased aggression and fear conditioning, and decreased social and exploratory investigative behaviors. Our objective was to measure MAOA binding in prefrontal cortex and concurrently evaluate a broad range of validated personality traits. We hypothesized that prefrontal MAOA binding would correlate negatively with angry-hostility, a trait related to aggression/anger, and positively with traits intuitively related to adaptive investigative behavior. Participants were aged 19-49 years, healthy and non-smoking. MAOA binding was measured with [11C]harmine positron emission tomography (PET) in prefrontal brain regions and personality traits were measured with the NEO Personality Inventory Revised (NEO PI-R). Prefrontal MAOA binding correlated negatively with angry-hostility (r=-0.515, p=0.001) and positively with deliberation (r=0.514, p=0.001). In a two-factor regression model, these facets explained 38% of variance in prefrontal MAOA binding. A similar relationship was found in prefrontal cortex subregions. We propose a new continuum describing the relationship between personality and MAOA: deliberate/thoughtful contrasting aggressive/impulsive. Additionally, the association between high MAOA binding and greater deliberation may explain why some people have moderately high levels of MAOA, although very high levels occur during MDD. In health, higher MAOA binding is associated with an adaptive personality facet.

  3. Biosensor based on inhibition of monoamine oxidases A and B for detection of β-carbolines.

    Science.gov (United States)

    Radulescu, Maria-Cristina; Bucur, Madalina-Petruta; Bucur, Bogdan; Radu, Gabriel Lucian

    2015-05-01

    β-Carbolines are inhibitors of monoamine oxidases (MAO-A and MAO-B) and can be found in foods, hallucinogenic plant or various drugs. We have developed a fast analysis method for β-carbolines based on the inhibition of MAO. The enzymes were immobilized on screen-printed electrodes modified with a stabilized film of Prussian blue that contain also copper. We have used benzylamine as substrate for the enzymatic reaction and the hydrogen peroxide was measured amperometrically at -50 mV. The detection limits obtained were 5.0 µM for harmane and 2.5 µM for both harmaline and norharmane. The MAO-A is inhibited by all three tested β-carbolines (harmane, norharmane, and harmaline) while MAO-B is inhibited only by norharmane. The presence of norharmane in mixtures of β-carbolines can be identified based on the difference between the cumulative inhibition of MAO-A by all β-carbolines and MAO-B inhibition. The developed biosensors were used for food analysis.

  4. Is fetal brain monoamine oxidase inhibition the missing link between maternal smoking and conduct disorders?

    Science.gov (United States)

    Baler, Ruben D; Volkow, Nora D; Fowler, Joanna S; Benveniste, Helene

    2008-05-01

    Smoking is the leading cause of preventable illness in the world today. Prenatal cigarette smoke exposure (PCSE) is a particularly insidious form because so many of its associated health effects befall the unborn child and produce behavioural outcomes that manifest themselves only years later. Among these are the associations between PCSE and conduct disorders, which have been mostly ascribed to the deleterious effects of nicotine on the fetal brain. Here we hypothesize that inhibition of brain monoamine oxidase (MAO) during fetal brain development, secondary to maternal cigarette smoking and in addition to nicotine, is a likely contributor to this association. MAOs play a central role in monoaminergic balance in the brain, and their inhibition during fetal development - but not during adult life - is known to result in an aggressive phenotype in laboratory animals. This paper provides theoretical and experimental support for the notion that cigarette smoke-induced inhibition of MAO in the fetal brain, particularly when it occurs in combination with polymorphisms in the MAOA gene that lead to lower enzyme concentration in the brain, may result in brain morphologic and functional changes that enhance the risk of irritability, poor self-control and aggression in the offspring. It also encourages research to evaluate whether the interaction of smoking exposure during fetal development and MAOA genotype increases the risk for conduct disorder over that incurred by mere fetal exposure to tobacco smoke.

  5. Simultaneous determination of cadaverine and putrescine using a disposable monoamine oxidase based biosensor.

    Science.gov (United States)

    Henao-Escobar, Wilder; Domínguez-Renedo, Olga; Asunción Alonso-Lomillo, M; Julia Arcos-Martínez, M

    2013-12-15

    The selective and simultaneous amperometric determination of putrescine (Put) and cadaverine (Cad) has been carried out using a novel design of screen-printed carbon electrode (SPCE) with two working electrodes connected in array mode. A mixture of 3% of tetrathiafulvalene (TTF), as mediator, and carbon ink was used for the construction of the screen-printed working electrode. The employment of different amounts of monoamine oxidase (MAO) enzyme on these modified TTF/SPCEs and the use of gold nanoparticles (AuNPs) allowed performing the simultaneous determination of both analytes. The amperometric detection has been performed by measuring the oxidation current of the mediator at a potential of+250 mV vs. screen-printed Ag/AgCl reference electrode. A linear response in the Cad concentration range from 19.6 till 107.1 µM and from 9.9 till 74.1 μM for Put was obtained at the MAO/AuNPs/TTF/SPCE biosensor. This device showed a capability of detection of 9.9 and 19.9±0.9 µM (n=4 α=β=0.05) and a precision of 4.9% and 10.3% in terms of relative standard deviation for Put and Cad, respectively. The developed biosensor was successfully applied to the simultaneous determination of Put and Cad in octopus samples.

  6. Monoamine Oxidases, Oxidative Stress, and Altered Mitochondrial Dynamics in Cardiac Ageing

    Directory of Open Access Journals (Sweden)

    Damien Maggiorani

    2017-01-01

    Full Text Available The advances in healthcare over the past several decades have resulted in populations now living longer. With this increase in longevity, a wider prevalence of cardiovascular diseases is more common and known to be a major factor in rising healthcare costs. A wealth of scientific evidence has implicated cell senescence as an important component in the etiology of these age-dependent pathologies. A number of studies indicate that an excess of reactive oxygen species (ROS contributes to trigger and accelerate the cardiac senescence processes, and a new role of monoamine oxidases, MAO-A and MAO-B, is emerging in this context. These mitochondrial enzymes regulate the level of catecholamines and serotonin by catalyzing their oxidative deamination in the heart. MAOs’ expression substantially increases with ageing (6-fold MAO-A in the heart and 4-fold MAO-B in neuronal tissue, and their involvement in cardiac diseases is supposedly related to the formation of ROS, via the hydrogen peroxide produced during the substrate degradation. Here, we will review the most recent advances in this field and describe why MAOs could be effective targets in order to prevent age-associated cardiovascular disease.

  7. Efficacy, safety, and patient preference of monoamine oxidase B inhibitors in the treatment of Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Bradley J Robottom

    2011-01-01

    Full Text Available Bradley J RobottomDepartment of Neurology, University of Maryland School of Medicine, Baltimore, MD, USAAbstract: Parkinson's disease (PD is the second most common neurodegenerative disease and the most treatable. Treatment of PD is symptomatic and generally focuses on the replacement or augmentation of levodopa. A number of options are available for treatment, both in monotherapy of early PD and to treat complications of advanced PD. This review focuses on rasagiline and selegiline, two medications that belong to a class of antiparkinsonian drugs called monoamine oxidase B (MAO-B inhibitors. Topics covered in the review include mechanism of action, efficacy in early and advanced PD, effects on disability, the controversy regarding disease modification, safety, and patient preference for MAO-B inhibitors.Keywords: monoamine oxidase inhibitors, rasagiline, selegiline, Parkinson's disease, efficacy, safety

  8. Desmodeleganine, a new alkaloid from the leaves of Desmodium elegans as a potential monoamine oxidase inhibitor.

    Science.gov (United States)

    Zhi, Kang-Kang; Yang, Zhong-Duo; Shi, Dan-Feng; Yao, Xiao-Jun; Wang, Ming-Gang

    2014-10-01

    Desmodeleganine (1), a new potential monoamine oxidase inhibitor, along with three known alkaloids, bufotenin (2), hydroxy-N, N-dimethyltryptamine N(12)-oxide (3), 2-(5-methoxy-1H-indol-3-yl)-N, and N-dimethylethylamine (4) were isolated from the leaves of Desmodium elegans. Their structures were elucidated by IR, MS, 1D and 2D NMR spectra. 1 showed strong monoamine oxidase inhibitory activity with IC50 value of 13.92 ± 1.5 μM, when the IC50 value of iproniazid as a standard was 6.5 ± 0.5 μM. The molecular modeling was also performed to explore the binding mode of compounds 1, 2 at the active site of MAO-A and MAO-B.

  9. Genetic studies of two inherited human phenotypes : Hearing loss and monoamine oxidase activity

    OpenAIRE

    Balciuniene, Jorune

    2001-01-01

    This thesis focuses on the identification of genetic factors underlying two inherited human phenotypes: hearing loss and monoamine oxidase activity. Non-syndromic hearing loss segregating in a Swedish family was tested for linkage to 13 previously reported candidate loci for hearing disabilities. Linkage was found to two loci: DFNA12 (llq22-q24) and DFNA2 (lp32). A detailed analysis of the phenotypes and haplotypes shared by the affected individuals supported the hypothesis of digenic inheri...

  10. Inhibitory effect of acetylcholine on monoamine oxidase A and B activity in different parts of rat brain.

    Science.gov (United States)

    Osman, Mohamed Y; Osman, Hassan M Y

    2008-01-01

    Acetylcholine (CAS 60-31-1, ACh), which is similar in its chemical structure to the carbamate aldicarb, was found to inhibit brain monoamine oxidase isoenzymes, namely MAO-A and B. The effect of ACh on both isoenzymes extracted from the whole brain of male albino rats and its different parts (frontal cortex, basal ganglia, cerebellum, pons and medulla oblongata) was studied. The results indicated that ACh inhibited MAO-A from the cerebellum and MAO-B from the basal ganglia more than MAO iso-enzymes from other brain parts. The inhibition was of the competitive type. It was also found that the enzyme inhibitor dissociation constants (Ki) and the affinity constants (Ki/Km) of MAO-A were higher than those of MAO-B.

  11. Synthetic and Natural Monoamine Oxidase Inhibitors as Potential Lead Compounds for Effective Therapeutics.

    Science.gov (United States)

    Pathak, Ashish; Srivastava, Amit K; Singour, Pradeep K; Gouda, Panchanan

    2016-01-01

    Monoamine oxidases A and B (MAO-A and B) play a critical role in the metabolism of intracellular neurotransmitters of the central nervous system. For decades, MAO inhibitors have proven their clinical efficacy as potential drug targets for several neurological and neurodegenerative diseases. Use of first generation non selective MAO inhibitors as neuropsychiatric drugs elicited several side effects like hypertensive crisis and cheese reaction. Therefore their use is now limited due to non-selectivity towards MAO isoforms and inhibition of metabolizing enzymes like cytochrome P450. Development of selective and specific MAO inhibitors like moclobemide, toloxatone improves their efficacy as disease-modifying effects in monotherapy as well as adjunctive therapy. Recently a lot of research has been done to elucidate the pharmacological potential of medicinal plants and their isolated bioactive constituents having MAO inhibitory activity. Herbs containing MAO inhibitors are extensively used for the development of potent synthetic drugs and as safe and effective alternatives to the available synthetic drugs in the treatment of neurodegenerative diseases such as depression, Parkinson and Alzheimer's. In several diseases like Parkinson natural MAO inhibitors prevented the neuron denaturalization by their dual action via enhancing neurotransmission of dopamine as well as lowering the generation of free radicals and toxins. Currently development of selective MAO inhibitors is still under study to achieve more effective therapies by using Computer Aided Drug Designing, Ligand-based models and structure-activity hypothesis. These approaches also facilitate understanding the interaction of newly designed molecule with MAO enzymes and the rationalization of probable mechanisms of action.

  12. Differences in Monoamine Oxidase Activity in the Brain of Wistar and August Rats with High and Low Locomotor Activity: A Cytochemical Study.

    Science.gov (United States)

    Sergutina, A V; Rakhmanova, V I

    2016-06-01

    Monoamine oxidase activity was quantitatively assessed by cytochemical method in brain structures (layers III and V of the sensorimotor cortex, caudate nucleus, nucleus accumbens, hippocampal CA3 field) of rats of August line and Wistar population with high and low locomotor activity in the open fi eld test. Monoamine oxidase activity (substrate tryptamine) predominated in the nucleus accumbens of Wistar rats with high motor activity in comparison with rats with low locomotor activity. In August rats, enzyme activity (substrates tryptamine and serotonin) predominated in the hippocampus of animals with high motor activity. Comparison of August rats with low locomotor activity and Wistar rats with high motor activity (i.e. animals demonstrating maximum differences in motor function) revealed significantly higher activity of the enzyme (substrates tryptamine and serotonin) in the hippocampus of Wistar rats. The study demonstrates clear-cut morphochemical specificity of monoaminergic metabolism based on the differences in the cytochemical parameter "monoamine oxidase activity", in the studied brain structures, responsible for the formation and realization of goal-directed behavior in Wistar and August rats.

  13. The monoamine oxidase inhibition properties of selected structural analogues of methylene blue.

    Science.gov (United States)

    Delport, Anzelle; Harvey, Brian H; Petzer, Anél; Petzer, Jacobus P

    2017-06-15

    The thionine dye, methylene blue (MB), is a potent inhibitor of monoamine oxidase (MAO) A, a property that may, at least in part, mediate its antidepressant effects in humans and animals. The central inhibition of MAO-A by MB has also been linked to serotonin toxicity (ST) which may arise when MB is used in combination with serotonergic drugs. Structural analogues and the principal metabolite of MB, azure B, have also been reported to inhibit the MAO enzymes, with all compounds exhibiting specificity for the MAO-A isoform. To expand on the structure-activity relationships (SARs) of MAO inhibition by MB analogues, the present study investigates the human MAO inhibition properties of five MB analogues: neutral red, Nile blue, new methylene blue, cresyl violet and 1,9-dimethyl methylene blue. Similar to MB, these analogues also are specific MAO-A inhibitors with cresyl violet (IC50=0.0037μM), Nile blue (IC50=0.0077μM) and 1,9-dimethyl methylene blue (IC50=0.018μM) exhibiting higher potency inhibition compared to MB (IC50=0.07μM). Nile blue also represents a potent MAO-B inhibitor with an IC50 value of 0.012μM. From the results it may be concluded that non-thionine MB analogues (e.g. cresyl violet and Nile blue) also may exhibit potent MAO inhibition, a property which should be considered when using these compounds in pharmacological studies. Benzophenoxazines such as cresyl violet and Nile blue are, similar to phenothiazines (e.g. MB), representative of high potency MAO-A inhibitors with a potential risk of ST. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. New insights into the biological properties of Crocus sativus L.: chemical modifications, human monoamine oxidases inhibition and molecular modeling studies.

    Science.gov (United States)

    De Monte, Celeste; Carradori, Simone; Chimenti, Paola; Secci, Daniela; Mannina, Luisa; Alcaro, Francesca; Petzer, Anél; N'Da, Clarina I; Gidaro, Maria Concetta; Costa, Giosuè; Alcaro, Stefano; Petzer, Jacobus P

    2014-07-23

    Although there are clinical trials and in vivo studies in literature regarding the anxiolytic and antidepressant activities of the components of Crocus sativus L., their effects on the human monoamine oxidases (hMAO-A and hMAO-B), enzymes which are involved in mental disorders and neurodegenerative diseases, have not yet been investigated. We have thus examined the hMAO inhibitory activities of crocin and safranal (the most important active principles in saffron) and, subsequently, designed a series of safranal derivatives to evaluate which chemical modifications confer enhanced inhibition of the hMAO isoforms. Docking simulations were performed in order to identify key molecular recognitions of these inhibitors with both isoforms of hMAO. In this regard, different mechanisms of action were revealed. This study concludes that safranal and crocin represent useful leads for the discovery of novel hMAO inhibitors for the clinical management of psychiatric and neurodegenerative disorders.

  15. Effect of short-time exposures to nickel and lead on brain monoamine oxidase from Danio rerio and Poecilia reticulata.

    Science.gov (United States)

    Senatori, Ornella; Setini, Andrea; Scirocco, Annunziata; Nicotra, Antonietta

    2009-06-01

    The aim of this work was to verify, in two small size freshwater teleosts Danio rerio and Poecilia reticulata, the effects of short-time exposures (24 and 72 h) to a sublethal dose (500 microg/L) of nickel and lead, on brain monoamine oxidase (MAO), an important neural enzyme. The 24-h treatment using both metals caused a strong reduction of MAO activity in D. rerio brain, whereas causing a slight MAO activity stimulation in P. reticulata brain. The same treatment in both species did not affect the brain MAO mRNA production as showed by RT-PCR. Extending the duration of treatment as far as 72 h, partly (D. rerio) or completely (P. reticulata) reversed the metal effects on brain MAO activity suggesting that mechanisms to neutralize the metals had been activated.

  16. Coumarin versus Chromone Monoamine Oxidase B Inhibitors: Quo Vadis?

    Science.gov (United States)

    Fonseca, André; Reis, Joana; Silva, Tiago; Matos, Maria João; Bagetta, Donatella; Ortuso, Francesco; Alcaro, Stefano; Uriarte, Eugenio; Borges, Fernanda

    2017-08-24

    Because of the lack of significant disease-modifying drugs for neurodegenerative disorders, a pressing need for new chemical entities endowed with IMAO-B still exists. Within this framework, and for the first time, a study was performed to compare coumarin- and chomone-3-phenylcarboxamide scaffolds. Compounds 10a and 10b were the most potent, selective, and reversible noncompetitive IMAO-B. The benzopyrone sp(2) oxygen atom was found to be position independent and a productive contributor for the ligand-enzyme complex stability.

  17. Chromone-2- and -3-carboxylic acids inhibit differently monoamine oxidases A and B.

    Science.gov (United States)

    Alcaro, Stefano; Gaspar, Alexandra; Ortuso, Francesco; Milhazes, Nuno; Orallo, Francisco; Uriarte, Eugenio; Yáñez, Matilde; Borges, Fernanda

    2010-05-01

    Chromone carboxylic acids were evaluated as human monoamine oxidase A and B (hMAO-A and hMAO-B) inhibitors. The biological data indicated that only chromone-3-carboxylic acid is a potent hMAO-B inhibitor, with a high degree of selectivity for hMAO-B compared to hMAO-A. Conversely the chromone-2-carboxylic acid resulted almost inactive against both MAO isoforms. Docking experiments were performed to elucidate the reasons of the different MAO IC(50) data and to explain the absence of activity versus selectivity, respectively. 2010 Elsevier Ltd. All rights reserved.

  18. Monoamine oxidase B inhibitors from the fruits of Opuntia ficus-indica var. saboten.

    Science.gov (United States)

    Han, Y N; Choo, Y; Lee, Y C; Moon, Y I; Kim, S D; Choi, J W

    2001-02-01

    Three varieties of methyl citrate and 1-methyl malate were isolated from the fruits of Opuntia ficus-indica var. saboten Makino through in vitro bioassay-guided isolation for the inhibition on monoamine oxidase(MAO). The IC50 values for MAO-B of 1-monomethyl citrate, 1,3-dimethyl citrate, trimethyl citrate and 1-methyl malate were 0.19, 0.23, 0.61 and 0.25 mM, respectively. However, on MAO-A, their inhibitions showed only marginal activity.

  19. Study of a possible role of the monoamine oxidase A (MAOA) gene in paranoid schizophrenia among a Chinese population.

    Science.gov (United States)

    Sun, Yuhui; Zhang, Jiexu; Yuan, Yanbo; Yu, Xin; Shen, Yan; Xu, Qi

    2012-01-01

    Monoamine oxidase A (MAOA) is the enzyme responsible for degradation of several monoamines, such as dopamine and serotonin that are considered as being two of the most important neurotransmitters involved in the pathophysiology of schizophrenia. To study a possible role of the MAOA gene in conferring susceptibility to schizophrenia, the present study genotyped the variable number of tandem repeat (VNTR) polymorphism and 41 SNPs across this gene among 555 unrelated patients with paranoid schizophrenia and 567 unrelated healthy controls. Quantitative real-time PCR analysis was employed to quantify expression of MAOA mRNA in 73 drug-free patients. While none of these genotyped DNA markers showed allelic association with paranoid schizophrenia, haplotypic association was found for the VNTR-rs6323, VNTR-rs1137070, and VNTR-rs6323-rs1137070 haplotypes in female subjects. Nevertheless, no significant change of the expression of MAOA mRNA was detected in either female or male patients with paranoid schizophrenia. Our study suggests that the interaction between genetic variants within the MAOA gene may contribute to an increased risk of paranoid schizophrenia, but the precise mechanism needs further investigation.

  20. DNA cloning of human liver monoamine oxidase A and B: Molecular basis of differences in enzymatic properties

    Energy Technology Data Exchange (ETDEWEB)

    Back, A.W.J.; Lan, N.C.; Johnson, D.L.; Abell, C.W.; Bembenek, M.E.; Kwan, S.W.; Seeburg, P.H.; Shih, J.C. (Univ. of Heidelberg (West Germany))

    1988-07-01

    The monoamine oxidases play a vital role in the metabolism of biogenic amines in the central nervous system and in peripheral tissues. Using oligonucleotide probes derived from three sequenced peptide fragments, the authors have isolated cDNA clones that encode the A and B forms of monoamine oxidase and have determined the nucleotide sequences of these cDNAs. Comparison of the deduced amino acid sequences shows that the A and B forms have subunit molecular weights of 59,700 and 58,800, respectively, and have 70% sequence identity. Both sequences contain the pentapeptide Ser-Gly-Gly-Cys-Tyr, in which the obligatory cofactor FAD is covalently bound to cysteine. Based on differences in primary amino acid sequences and RNA gel blot analysis of mRNAs, the A and B forms of monoamine oxidase appear to be derived from separate genes.

  1. Catechol O-methyltransferase and monoamine oxidase A genotypes, and plasma catecholamine metabolites in bipolar and schizophrenic patients.

    Science.gov (United States)

    Zumárraga, Mercedes; Dávila, Ricardo; Basterreche, Nieves; Arrue, Aurora; Goienetxea, Biotza; Zamalloa, María I; Erkoreka, Leire; Bustamante, Sonia; Inchausti, Lucía; González-Torres, Miguel A; Guimón, José

    2010-01-01

    Metabolites of dopamine and norepinephrine measured in the plasma have long been associated with symptomatic severity and response to treatment in schizophrenic, bipolar and other psychiatric patients. Plasma concentrations of catecholamine metabolites are genetically regulated. The genes encoding enzymes that are involved in the synthesis and degradation of these monoamines are candidate targets for this genetic regulation. We have studied the relationship between the Val158Met polymorphism in catechol O-methyltransferase gene, variable tandem repeat polymorphisms in the monoamine oxidase A gene promoter, and plasma concentrations of 3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid and homovanillic acid in healthy control subjects as well as in untreated schizophrenic and bipolar patients. We found that the Val158Met substitution in catechol O-methyltransferase gene influences the plasma concentrations of homovanillic and 3,4-dihydroxyphenylacetic acids. Although higher concentrations of plasma homovanillic acid were found in the high-activity ValVal genotype, this mutation did not affect the plasma concentration of 3-methoxy-4-hydroxyphenylglycol. 3,4-dihydroxyphenylacetic acid concentrations were higher in the low-activity MetMet genotype. Interestingly, plasma values 3-methoxy-4-hydroxyphenylglycol were greater in schizophrenic patients and in bipolar patients than in healthy controls. Our results are compatible with the previously reported effect of the Val158Met polymorphism on catechol O-methyltransferase enzymatic activity. Thus, our results suggest that this polymorphism, alone or associated with other polymorphisms, could have an important role in the genetic control of monoamine concentration and its metabolites.

  2. Cognitive abnormalities and hippocampal alterations in monoamine oxidase A and B knockout mice.

    Science.gov (United States)

    Singh, Chanpreet; Bortolato, Marco; Bali, Namrata; Godar, Sean C; Scott, Anna L; Chen, Kevin; Thompson, Richard F; Shih, Jean C

    2013-07-30

    The monoamine oxidase isoenzymes (MAOs) A and B play important roles in the homeostasis of monoaminergic neurotransmitters. The combined deficiency of MAO A and B results in significantly elevated levels of serotonin (5-hydroxytryptamine), norepinephrine, dopamine, and β-phenylethylamine; in humans and mice, these neurochemical changes are accompanied by neurodevelopmental perturbations as well as autistic-like responses. Ample evidence indicates that normal levels of monoamines in the hippocampus, amygdala, frontal cortex, and cerebellum are required for the integrity of learning and memory. Thus, in the present study, the cognitive status of MAO A/B knockout (KO) mice was examined with a wide array of behavioral tests. In comparison with male wild-type littermates, MAO A/B KO mice exhibited abnormally high and overgeneralized fear conditioning and enhanced eye-blink conditioning. These alterations were accompanied by significant increases in hippocampal long-term potentiation and alterations in the relative expression of NMDA glutamate receptor subunits. Our data suggest that chronic elevations of monoamines, because of the absence of MAO A and MAO B, cause functional alterations that are accompanied with changes in the cellular mechanisms underlying learning and memory. The characteristics exhibited by MAO A/B KO mice highlight the potential of these animals as a useful tool to provide further insight into the molecular bases of disorders associated with abnormal monoaminergic profiles.

  3. Histaminergic system in the cat hypothalamus with reference to type B monoamine oxidase.

    Science.gov (United States)

    Lin, J S; Kitahama, K; Fort, P; Panula, P; Denney, R M; Jouvet, M

    1993-04-15

    It is known that histamine (HA) and type B monoamine oxidase (MAO-B), an enzyme involved in its metabolism, are present in the posterior hypothalamus, but the sites where MAO-B intervenes in HA metabolism remain uncertain. The present study examined and compared the detailed distribution and morphology of neurons immunoreactive to HA (HA-ir) and MAO-B (MAO-B-ir) in the cat hypothalamus. HA-ir neurons were localized almost exclusively in the posterior hypothalamus with the largest group in the tuberomammillary nucleus and adjacent areas. MAO-B-ir staining was detected in the vast majority of HA-ir neurons, suggesting that the degradation of tele-methylhistamine (t-MHA), the direct metabolite of HA, may occur within these cells. Nevertheless, a few HA-ir cells showed no detectable or very weak MAO-B-ir labeling; a small group of neurons containing MAO-B alone was detected in the area dorsolateral to the caudal part of the arcuate nucleus. Numerous HA-ir axons and terminal-like structures were distributed unevenly in virtually all hypothalamic regions. One of their principal trajectories ascended through the ventrolateral part of the hypothalamus and rostrally formed an axon column, which ascended into the preoptic area and contributed fibers to the diagonal band of Broca and bed nucleus of the stria terminalis. Other HA-ir axons passed laterally, dorsal to the zona incerta or ventrally through a narrow zone dorsal to the optic tract. Numerous long HA-ir axons coursed dorsomedially from the ventrolateral posterior hypothalamus to the dorsal hypothalamic area. Many are oriented vertically to the thalamus in the midline. MAO-B-ir axons and fibers were detectable throughout the hypothalamus and overlapped the areas distributing HA-ir fibers. They were, however, weaker in staining intensity and apparently fewer than the HA-ir fibers. MAO-B-ir glial cells were numerous in all hypothalamic structures rich in HA-ir fibers. These results suggest that the metabolism of t

  4. Lack of platelet monoamine oxidase activity in Cebus monkeys (Cebus albifrons).

    Science.gov (United States)

    Heintz, R; Richardson, M A; Perumal, A S; Casey, D E

    1989-01-01

    1. Recent evidence suggests that monoamine oxidase (MAO) plays an important role modulating the extrapyramidal syndromes produced by neuroleptic drugs in both human and nonhuman primates. 2. To evaluate the possibility of using peripheral blood platelet MAO-B levels as indices of central nervous system MAO-B effects, we measured platelet MAO-B levels in Cebus monkeys that were previously tested with neuroleptics (N = 36) or drug naive (N = 6). 3. No platelet MAO-B was consistently detectable in these blood samples. 4. Thus platelet measures of MAO-B do not reliably reflect brain MAO-B function in nonhuman primates and do not offer a useful model for studying blood-brain MAO-B relationships.

  5. Monoamine oxidase and transaminase screening: biotransformation of 2-methyl-6-alkylpiperidines by Neopestalotiopsis sp. CBMAI 2030.

    Science.gov (United States)

    Costa, Jonas Henrique; da Costa, Bruna Zucoloto; de Angelis, Derlene Attili; Marsaioli, Anita Jocelyne

    2017-08-01

    High-throughput screening detected transaminases (TAs) and monoamine oxidases (MAOs) in fungi by applying a fluorogenic probe. Strains F026, F037, F041, F053, and F057 showed the highest enzymatic conversions (31, 60, 30, 40, and 32%, respectively) and where evaluated for their ability to transform piperidines. Strain F053 (Neopestalotiopsis sp. CBMAI 2030) revealed unusual enzymatic activity to deracemize 2-methyl-6-alkylpiperidines. Neopestalotiopsis sp. CBMAI 2030 was capable to convert 2-methyl-6-propylpiperidine, 2-methyl-6-butylpiperidine, and 2-methyl-6-pentylpiperidine in piperideine with 11, 14, and 24% conversion, respectively. The activity was enhanced by cultivating the fungus with 2-methyl-6-pentylpiperidine (38% conversion and 73% ee).

  6. ”Ping-pong gaze” secondary to monoamine oxidase inhibitor overdose

    Directory of Open Access Journals (Sweden)

    Amy Attaway

    2016-01-01

    Full Text Available An infrequent manifestation of monoamine oxidase inhibitor (MAOI toxicity is “ping-pong gaze” (PPG. We describe the case of a 26-year-old female who was found unresponsive after taking 40 tablets of phenelzine. On presentation to the hospital, her eyes were moving in characteristic “ping pong” fashion. After 6 hours her gaze terminated. The following day her neurologic exam was benign and she had no long-term sequelae. While the etiology of PPG is unknown, it is most often seen with irreversible structural brain damage. However, a detailed literature review revealed that previous cases of MAOI toxicity where the patient survived have all had complete neurologic recovery.

  7. Synthesis and biological assessment of novel 2-thiazolylhydrazones and computational analysis of their recognition by monoamine oxidase B.

    Science.gov (United States)

    Distinto, Simona; Yáñez, Matilde; Alcaro, Stefano; Cardia, M Cristina; Gaspari, Marco; Sanna, M Luisa; Meleddu, Rita; Ortuso, Francesco; Kirchmair, Johannes; Markt, Patrick; Bolasco, Adriana; Wolber, Gerhard; Secci, Daniela; Maccioni, Elias

    2012-02-01

    Monoamine oxidase B (MAO-B) is a promising target for the treatment of neurodegenerative disorders. We report the synthesis and the biological evaluation of halogenated derivatives of 1-aryliden-2-(4-phenylthiazol-2-yl)hydrazines. The fluorinated series shows interesting activity and great selectivity toward the human recombinant MAO-B isoform expressed in baculovirus infected BTI insect cells. The multiple crystal structures alignment of the enzyme highlighted pronounced induced fit (IF) adaptations with respect to bound ligands. Therefore, IF docking (IFD) experiments and molecular dynamic (MD) simulations were carried out to reveal the putative binding mode and to explain the experimentally observed differences in the activity of 1-(aryliden-2-(4-(4-chlorophenyl)thiazol-2-yl)hydrazines. The importance of water molecules within the binding site was also investigated. These are known to play an important role in the binding site cavity and to mediate protein-ligand interactions. Detailed analyses of the trajectories provide insights on the chemical features required for the activity of this scaffold. In particular it was highlighted the importance of fluorine atom interacting with the water close to the cofactor and the influence of steric bulkiness of substituents in the arylidene moiety. Free energy perturbation (FEP) analysis confirmed experimental data. The information we deduced will help to develop novel high-affinity MAO-B inhibitors.

  8. MicroRNA-142 reduces monoamine oxidase A expression and activity in neuronal cells by downregulating SIRT1.

    Directory of Open Access Journals (Sweden)

    Amrita Datta Chaudhuri

    Full Text Available Aberrant expression of microRNAs (miRs has been implicated in the pathogenesis of several neurodegenerative disorders. In HIV-associated neurocognitive disorders (HAND, miR-142 was found to be upregulated in neurons and myeloid cells in the brain. We investigated the downstream effects of chronic miR-142 upregulation in neuronal cells by comparing gene expression in stable clones of the human neuroblastoma cell line BE(2M17 expressing miR-142 to controls. Microarray analysis revealed that miR-142 expression led to a reduction in monoamine oxidase (MAO A mRNA, which was validated by qRT-PCR. In addition to the mRNA, the MAOA protein level and enzyme activity were also reduced. Examination of primary human neurons revealed that miR-142 expression indeed resulted in a downregulation of MAOA protein level. Although MAOA is not a direct target of miR-142, SIRT1, a key transcriptional upregulator of MAOA is, thus miR-142 downregulation of MAOA expression is indirect. MiR-142 induced decrease in MAOA expression and activity may contribute to the changes in dopaminergic neurotransmission reported in HAND.

  9. Pressor response to intravenous tyramine in healthy subjects after safinamide, a novel neuroprotectant with selective, reversible monoamine oxidase B inhibition.

    Science.gov (United States)

    Cattaneo, Carlo; Caccia, Carla; Marzo, Antonio; Maj, Roberto; Fariello, Ruggero G

    2003-01-01

    Safinamide is a novel neuroprotectant combining sodium and calcium channel blocking properties with selective, reversible monoamine oxidase type B (MAO B) inhibition. Phase 1 studies have demonstrated that in healthy volunteers, the ED50 (a dose that inhibits enzyme activity by 50% in 50% of treated subjects) for MAO B inhibition is 87.5 microg/kg/day orally, and that no MAO A inhibition occurs after 10-mg/kg oral dosing. To assess the risk of inducing the "cheese effect," the effect of safinamide and placebo on the pressor response to tyramine was investigated in a group of healthy male volunteers. The study was an open, single-dose placebo-controlled trial with the 2 treatments in sequence. An increase of 30 mm Hg systolic blood pressure was obtained by intravenous tyramine administered by 0.5-mg incremental boluses injected at 15-minute intervals. The amount of tyramine necessary to achieve such a blood pressure increase was the same after the safinamide 2-mg/kg oral load compared with placebo. These results suggest that dietary restrictions for food with high tyramine content should not be required under safinamide treatment.

  10. Patterns of renal dopamine release to regulate diuresis and natriuresis during volume expansion. Role of renal monoamine-oxidase.

    Science.gov (United States)

    de Luca Sarobe, Verónica; Di Ciano, Luis; Carranza, Andrea M; Levin, Gloria; Arrizurieta, Elvira E; Ibarra, Fernando R

    2010-01-01

    Diuretic and natriuretic effects of renal dopamine (DA) are well established. However, in volume expansion the pattern of renal DA release into urine (UDAV) and the role of enzymes involved in DA synthesis/degradation have not yet been defined. The objective was to determine the pattern of UDAV during volume expansion and to characterize the involvement of monoamine-oxidase (MAO) and aromatic amino-acid decarboxylase (AADC) in this response. In this study male Wistar rats were expanded with NaCl 0.9% at a rate of 5% BWt per hour. At the beginning of expansion three groups received a single drug injection as follows: C (vehicle, Control), IMAO (MAO inhibitor Pargyline, 20 mg/kg BWt, i.v.) and BNZ (AADC inhibitor Benserazide, 25 mg/kg BWt, i.v.). Results revealed that in C rats UDAV (ng/30 min/100g BWt) increased in the first 30 min expansion from 11.5 +/- 1.20 to 21.8 +/- 3.10 (p diuresis and natriuresis over controls. BNZ abolished the early UDAV peak to 3.2+/-0.72 (p diuresis were diminished by BNZ treatment. Results indicate that an increment in renal DA release into urine occurs early in expansion and in a peak-shaped way. In this response MAO plays a predominant role.

  11. Inhibition of monoamine oxidase by furazolidone in the chicken and the influence of the alimentary flora thereon.

    Science.gov (United States)

    Ali, B H; Bartlet, A L

    1980-01-01

    1 The addition of furazolidone to the feed at the therapeutic level (0.04% w/w, 10 days) inhibited monoamine oxidase (MAO) activity by 47 to 72% in chicken duodenal mucosa, heart and brain, but in the liver the enzyme activity was unaffected by the treatment. 2 Furazolidone (200 mg/kg) administered by crop tube inhibited MAO activities in duodenal mucosa, liver, heart and brain. 3 Furazolidone (200 mg/kg) injected intramuscularly did not inhibit MAO activity in the chicken. 4 Pretreatment of the chickens with intramuscular neomycin did not antagonize the inhibition of MAO activity produced by furazolidone (200 mg/kg, crop tube). 5 Pretreatment with neomycin by crop tube to suppress the alimentary flora significantly reduced the effect of furazolidone on MAO activity, suggesting that the drug was transformed by the alimentary flora to an active metabolite which subsequently inhibited MAO activity in other organs. 6 Furazolidone in the feed (0.04% w/w, 10 days) or administered by crop tube (200 mg/kg) had no effect on the activity of aminopyrine demethylase in chicken liver. 7 The activity of aspartate transaminase in plasma was unaffected by the addition of furazolidone to the feed (0.04% w/w, 10 days).

  12. Monoamine oxidase inhibitors: nature of their interaction with rabbit pancreatic islets to alter insluin secretion.

    Science.gov (United States)

    Feldman, J M; Chapman, B

    1975-12-01

    Using an in vitro rabbit pancreas system, we studied the effect of monoamine oxidase (MAO) inhibitors on flucose-stimulated insulin secretion. We evaluated the effect of both brief (15 min) and prolonged (60 min) exposure of pancreas segments to non-hydrazine (harmine, alpha-methyltryptamine, tranylcypromine and pargyline) and hydrazine (phenelzine, nialamide, iproniazid) type MAO inhibitors. All of the hydrazine type MAO inhibitors potentiated glucose-stimulated insulin secretion. Of the non-hydrazine inhibitors, only harmine and alpha-methyltryptamine potentiated glucose-stimulated insulin secretion. Hydrazine, although not itself an MAO inhibitor, also potentiated insulin secretion. Sixty minutes of exposure to tranylcypromine or alpha-methyltryptamine caused a decrease in insulin secretion. These MAO inhibitors are primary amines and primary amines can inhibit insulin secretion. The dopamine (DA) or serotonin (5-HT) content of the B-cells was increased by incubating rabbit pancreas with L-3, 4-dihydroxyphenylalanine (L-Dopa) or 5-hydroxytryptophan (5-HTP) for forty-five minutes prior to stimulation with glucose. Non-hydrazine MAO inhibitors increased dopamine inhibition of insulin secretion and either did not alter, or decreased serotonin inhibition of insulin secretion. Rabbit pancreatic islets were isolated using the collagenase digestion technique. The MAO activity of islet homogenates was determined using 5-HT and DA as substrates. Rabbit islet MAO has only one-tenth the specific activity against 5-HT (35 +/- 8.7 mumumoles/mg/min, M +/- SEM) that it has against DA (357 +/- 62.3 mumumoles/mg/min). This suggests that one reason that MAT inhibitors do not increase serotonin inhibition of insulin secretion is because MAO is not the major pathway for 5-HT inactivation in rabbit pancreatic islets. These studies suggest that MAO inhibitors alter insulin secretion, by both decreasing B-cell monoamine degradation and by mechanisms that do not involve MAO inhibition.

  13. The role of the monoamine oxidase A gene in moderating the response to adversity and associated antisocial behavior: a review

    Directory of Open Access Journals (Sweden)

    Buades-Rotger M

    2014-07-01

    Full Text Available Macià Buades-Rotger,1,2 David Gallardo-Pujol1,3 1Department of Personality, Faculty of Psychology, University of Barcelona, Barcelona, Spain; 2Department of Neurology, University of Lübeck, Lübeck, Germany; 3Institute for Brain, Cognition and Behavior (IR3C, University of Barcelona, Barcelona, Spain Abstract: Hereditary factors are increasingly attracting the interest of behavioral scientists and practitioners. Our aim in the present article is to introduce some state-of-the-art topics in behavioral genetics, as well as selected findings in the field, in order to illustrate how genetic makeup can modulate the impact of environmental factors. We focus on the most-studied polymorphism to date for antisocial responses to adversity: the monoamine oxidase A gene. Advances, caveats, and promises of current research are reviewed. We also discuss implications for the use of genetic information in applied settings. Keywords: behavioral genetics, antisocial behaviors, monoamine oxidase A

  14. NADPH oxidase: an enzyme for multicellularity?

    Science.gov (United States)

    Lalucque, Hervé; Silar, Philippe

    2003-01-01

    Multicellularity has evolved several times during the evolution of eukaryotes. One evolutionary pressure that permits multicellularity relates to the division of work, where one group of cells functions as nutrient providers and the other in specialized roles such as defence or reproduction. This requires signalling systems to ensure harmonious development of multicellular structures. Here, we show that NADPH oxidases are specifically present in organisms that differentiate multicellular structures during their life cycle and are absent from unicellular life forms. The biochemical properties of these enzymes make them ideal candidates for a role in intercellular signalling.

  15. Azure B, a metabolite of methylene blue, is a high-potency, reversible inhibitor of monoamine oxidase

    OpenAIRE

    Petzer, Anél; Harvey, Brian H; Wegener, Gregers; Petzer, Jacobus P.

    2012-01-01

    Methylene blue (MB) has been shown to act at multiple cellular and molecular targets and as a result possesses diverse medical applications. Among these is a high potency reversible inhibition of monoamine oxidase A (MAO-A) that may, at least in part, underlie its adverse effects but also its psycho- and neuromodulatory actions. MB is metabolized to yield N-demethylated products of which azure B, the monodemethyl species, is the major metabolite. Similar to MB, azure B also displa...

  16. Discovery of New Chemical Entities for Old Targets: Insights on the Lead Optimization of Chromone-Based Monoamine Oxidase B (MAO-B) Inhibitors.

    Science.gov (United States)

    Reis, Joana; Cagide, Fernando; Chavarria, Daniel; Silva, Tiago; Fernandes, Carlos; Gaspar, Alexandra; Uriarte, Eugenio; Remião, Fernando; Alcaro, Stefano; Ortuso, Francesco; Borges, Fernanda

    2016-06-23

    The discovery of new chemical entities endowed with potent, selective, and reversible monoamine oxidase B inhibitory activity is a clinically relevant subject. Therefore, a small library of chromone derivatives was synthesized and screened toward human monoamine oxidase isoforms (hMAO-A and hMAO-B). The structure-activity relationships studies strengthen the importance of the amide spacer and the direct linkage of carbonyl group to the γ-pyrone ring, along with the presence of meta and para substituents in the exocyclic ring. The most potent MAO-B inhibitors were N-(3'-chlorophenyl)-4-oxo-4H-chromene-3-carboxamide (20) (IC50 = 403 pM) and N-(3',4'-dimethylphenyl)-4-oxo-4H-chromene-3-carboxamide (27) (IC50 = 669 pM), acting as competitive and noncompetitive reversible inhibitors, respectively. Computational docking studies provided insights into enzyme-inhibitor interactions and a rationale for the observed selectivity and potency. Compound 27 stands out due to its favorable toxicological profile and physicochemical properties, which pointed toward blood-brain barrier permeability, thus being a valid candidate for subsequent animal studies.

  17. Radiochemistry devoted to the production of monoamine oxidase (MAO-A and MAO-B) ligands for brain imaging with positron emission tomography.

    Science.gov (United States)

    Kersemans, Ken; Van Laeken, Nick; De Vos, Filip

    2013-01-01

    Monoamine oxidase (MAO) belongs to a family of flavin-containing integral enzymes that are present in the outer mitochondrial membrane in neurons and glial cells in the central nervous system. These enzymes catalyze the oxidative deamination of various neurotransmitters, biogenic amines, and xenobiotics, thereby influencing their availability and physiological activity in brain and body. Over the past decades, many potential positron emission tomography tracers have been put forward to visualize MAO in the brain with varying success, and recent publications on the topic illustrate the continuing interest in the field. The present review gives an overview of the compounds that have been put forward as possible MAO tracers in the brain and focuses on the radiochemical procedures that have been developed to produce them up till now. Relevant radioligands are grouped by the main radiochemical strategies that have been employed to synthesize them, and some interesting details and findings that are crucial to the radiosyntheses are provided.

  18. The properties of B-form monoamine oxidase in mitochondria from monkey platelet.

    Science.gov (United States)

    Obata, Toshio; Aomine, Masahiro

    The present study was examined the effect of the properties of monkey platelet monoamine oxidase (MAO) based on inhibitor sensitivity. Monkey platelet showed a high MAO activity with beta-phenylethylamine (beta-PEA) as substrate and a very low A-form MAO activity with 5 hydroxytryptamine (5-HT) as substrate. Moreover, monkey platelet MAO was sensitive to the drugs deprenyl as B-form MAO inhibitor and less sensitive to clorgyline and harmaline as A form MAO inhibitor with beta-PEA as the B-form MAO substrate. B-form MAO from monkey platelet was more stable against heat treatment at 55 degrees C than B-form MAO in brain. After digestion with trypsin at 37 degrees C for 4 hrs, it was found that MAO from platelet was inhibited about 70% with beta-PEA as substrate with brain. The tricyclic antidepressant imipramine and nortriptyline inhibited B-form MAO activity more potency than B-form MAO in brain. However, when the noncyclic antidepressant nomifensine was used, monkey platelet B-form MAO activities were less potently inhibited. All these reagents were noncompetitive inhibitors of B form MAO in monkey platelet. The present studies demonstrated that monkey platelet MAO is a single of B-form MAO and sensitive to tricyclic antidepressants.

  19. Psychological traits and platelet monoamine oxidase activity in eating disorder patients: their relationship and stability.

    Science.gov (United States)

    Podar, Iris; Jaanisk, Maiken; Allik, Jüri; Harro, Jaanus

    2007-01-30

    Self-reported behavior and attitudes towards eating [Eating Disorder Inventory-2; Garner DM (1991). Eating Disorder Inventory-2: Professional Manual. Odessa, Fl.: Psychological Assessment Resources; Estonian version Podar I, Hannus A, Allik J (1999). Personality and Affectivity Characteristics Associated With Eating Disorders: a Comparison of Eating Disordered, Weight-Preoccupied, and Normal Samples. J Pers Assess; 73(1), 133-147] and the activity of platelet monoamine oxidase (MAO) was studied in 11 patients with anorexia nervosa (AN), 43 patients with bulimia nervosa (BN) and a healthy control group (n=138). Nineteen patients filled in the EDI-2 questionnaire and donated blood samples three times with three month intervals in order to determine platelet MAO activity. Eating disordered (ED) patients scored higher on all EDI-2 subscales and had lower MAO activity compared to the control group. They also scored higher than the control group on the Neuroticism domain but lower on the Extraversion, Openness, and Conscientiousness domains of the NEO-PI-R questionnaire. The average stability of MAO on different occasions (r=.56) was slightly smaller than the stability of the EDI-2 scores (r=.70). The lack of correlations between personality dispositions and MAO activity indicates that they have independent influence on eating disorders. A possible relationship between neurochemical mechanisms and psychological symptoms of eating disordered behavior is discussed.

  20. Monoamine oxidase A genotype is associated with gang membership and weapon use.

    Science.gov (United States)

    Beaver, Kevin M; DeLisi, Matt; Vaughn, Michael G; Barnes, J C

    2010-01-01

    A functional polymorphism in the promoter region of the monoamine oxidase A (MAOA) gene has been found to be associated with a broad range of antisocial phenotypes, including physical violence. At the same time, it is well known that gang members represent some of the most serious violent offenders. Even so, no research has ever examined the association between MAOA and gang membership. The aim of this study is to examine the association between MAOA and gang membership and between MAOA and weapon use. We examined the effects of MAOA by using a molecular genetic association research design. A nonclinical sample was used in this study. Participants were drawn from the National Longitudinal Study of Adolescent Health (1155 females, 1041 males). The outcome measures of this study are gang membership and weapon use. The low MAOA activity alleles conferred an increased risk of joining a gang and using a weapon in a fight for males but not for females. Moreover, among male gang members, those who used weapons in a fight were more likely to have a low MAOA activity allele when compared with male gang members who do not use weapons in a fight. Male carriers of low MAOA activity alleles are at risk for becoming a gang member and, once a gang member, are at risk for using weapons in a fight. Copyright 2010 Elsevier Inc. All rights reserved.

  1. Monoamine oxidase A gene DNA hypomethylation - a risk factor for panic disorder?

    Science.gov (United States)

    Domschke, Katharina; Tidow, Nicola; Kuithan, Henriette; Schwarte, Kathrin; Klauke, Benedikt; Ambrée, Oliver; Reif, Andreas; Schmidt, Hartmut; Arolt, Volker; Kersting, Anette; Zwanzger, Peter; Deckert, Jürgen

    2012-10-01

    The monoamine oxidase A (MAOA) gene has been suggested as a prime candidate in the pathogenesis of panic disorder. In the present study, DNA methylation patterns in the MAOA regulatory and exon 1/intron 1 region were investigated for association with panic disorder with particular attention to possible effects of gender and environmental factors. Sixty-five patients with panic disorder (44 females, 21 males) and 65 healthy controls were analysed for DNA methylation status at 42 MAOA CpG sites via direct sequencing of sodium bisulfate treated DNA extracted from blood cells. The occurrence of recent positive and negative life events was ascertained. Male subjects showed no or only very minor methylation with some evidence for relative hypomethylation at one CpG site in intron 1 in patients compared to controls. Female patients exhibited significantly lower methylation than healthy controls at 10 MAOA CpG sites in the promoter as well as in exon/intron 1, with significance surviving correction for multiple testing at four CpG sites (p≤0.001). Furthermore, in female subjects the occurrence of negative life events was associated with relatively decreased methylation, while positive life events were associated with increased methylation. The present pilot data suggest a potential role of MAOA gene hypomethylation in the pathogenesis of panic disorder particularly in female patients, possibly mediating a detrimental influence of negative life events. Future studies are warranted to replicate the present finding in independent samples, preferably in a longitudinal design.

  2. Assessment of Mitochondrial Dysfunction and Monoamine Oxidase Contribution to Oxidative Stress in Human Diabetic Hearts

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    O. M. Duicu

    2016-01-01

    Full Text Available Mitochondria-related oxidative stress is a pathomechanism causally linked to coronary heart disease (CHD and diabetes mellitus (DM. Recently, mitochondrial monoamine oxidases (MAOs have emerged as novel sources of oxidative stress in the cardiovascular system and experimental diabetes. The present study was purported to assess the mitochondrial impairment and the contribution of MAOs-related oxidative stress to the cardiovascular dysfunction in coronary patients with/without DM. Right atrial appendages were obtained from 75 patients randomized into 3 groups: (1 Control (CTRL, valvular patients without CHD; (2 CHD, patients with confirmed CHD; and (3 CHD-DM, patients with CHD and DM. Mitochondrial respiration was measured by high-resolution respirometry and MAOs expression was evaluated by RT-PCR and immunohistochemistry. Hydrogen peroxide (H2O2 emission was assessed by confocal microscopy and spectrophotometrically. The impairment of mitochondrial respiration was substrate-independent in CHD-DM group. MAOs expression was comparable among the groups, with the predominance of MAO-B isoform but no significant differences regarding oxidative stress were detected by either method. Incubation of atrial samples with MAOs inhibitors significantly reduced the H2O2 in all groups. In conclusion, abnormal mitochondrial respiration occurs in CHD and is more severe in DM and MAOs contribute to oxidative stress in human diseased hearts with/without DM.

  3. Inhibition of monoamine oxidase by selected C6-substituted chromone derivatives.

    Science.gov (United States)

    Legoabe, Lesetja J; Petzer, Anél; Petzer, Jacobus P

    2012-03-01

    Chromone has been reported to be a useful scaffold for the design of monoamine oxidase (MAO) inhibitors. In an attempt to discover highly potent MAO inhibitors and to contribute to the known structure-activity relationships (SAR) of MAO inhibition by chromones, in the present study, we have synthesized a series of chromone derivatives substituted at C6 with a variety of alkyloxy substituents, and evaluated the resulting compounds as inhibitors of recombinant human MAO-A and -B. The results document that the C6-substituted chromones are potent reversible MAO-B inhibitors with IC(50) values in the low nM range (2-76 nM). The chromones were also found to bind reversibly to MAO-A, but with lower affinities compared to MAO-B. It may therefore be concluded that C6-substituted chromones are highly potent MAO-B selective inhibitors and promising lead compounds for the development of therapy for neurodegenerative disorders such as Parkinson's disease. The results of this study are discussed with reference to possible binding orientations of a selected C6-substituted chromone in the active site cavities of MAO-A and -B. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  4. Chromone, a privileged scaffold for the development of monoamine oxidase inhibitors.

    Science.gov (United States)

    Gaspar, Alexandra; Silva, Tiago; Yáñez, Matilde; Vina, Dolores; Orallo, Franscisco; Ortuso, Francesco; Uriarte, Eugenio; Alcaro, Stefano; Borges, Fernanda

    2011-07-28

    Two series of novel chromone derivatives were synthesized and investigated for their ability to inhibit the activity of monoamine oxidase. The SAR data indicate that chromone derivatives with substituents in position 3 of γ-pyrone nucleus act preferably as MAO-B inhibitors, with IC(50) values in the nanomolar to micromolar range. Almost all chromone 3-carboxamides display selectivity toward MAO-B. Identical substitutions on position 2 of γ-pyrone nucleus result in complete loss of activity in both isoforms (chromones 2-12 except 3 and 5). Notably, chromone (19) exhibits an MAO-B IC(50) of 63 nM, greater than 1000-fold selectivity over MAO-A, and behaves as a quasi-reversible inhibitor. Docking experiments onto the MAO binding of the most active compound highlight different interaction patterns among the isoforms A and B. The differential analysis of the solvation effects among the chromone isomers gave additional insight about the superior outline of the 3-substituted chromone derivatives.

  5. Oxidative stress by monoamine oxidases is causally involved in myofiber damage in muscular dystrophy.

    Science.gov (United States)

    Menazza, Sara; Blaauw, Bert; Tiepolo, Tania; Toniolo, Luana; Braghetta, Paola; Spolaore, Barbara; Reggiani, Carlo; Di Lisa, Fabio; Bonaldo, Paolo; Canton, Marcella

    2010-11-01

    Several studies documented the key role of oxidative stress and abnormal production of reactive oxygen species (ROS) in the pathophysiology of muscular dystrophies (MDs). The sources of ROS, however, are still controversial as well as their major molecular targets. This study investigated whether ROS produced in mitochondria by monoamine oxidase (MAO) contributes to MD pathogenesis. Pargyline, an MAO inhibitor, reduced ROS accumulation along with a beneficial effect on the dystrophic phenotype of Col6a1(-/-) mice, a model of Bethlem myopathy and Ullrich congenital MD, and mdx mice, a model of Duchenne MD. Based on our previous observations on oxidative damage of myofibrillar proteins in heart failure, we hypothesized that MAO-dependent ROS might impair contractile function in dystrophic muscles. Indeed, oxidation of myofibrillar proteins, as probed by formation of disulphide cross-bridges in tropomyosin, was detected in both Col6a1(-/-) and mdx muscles. Notably, pargyline significantly reduced myofiber apoptosis and ameliorated muscle strength in Col6a1(-/-) mice. This study demonstrates a novel and determinant role of MAO in MDs, adding evidence of the pivotal role of mitochondria and suggesting a therapeutic potential for MAO inhibition.

  6. Carnosine: effect on aging-induced increase in brain regional monoamine oxidase-A activity.

    Science.gov (United States)

    Banerjee, Soumyabrata; Poddar, Mrinal K

    2015-03-01

    Aging is a natural biological process associated with several neurological disorders along with the biochemical changes in brain. Aim of the present investigation is to study the effect of carnosine (0.5-2.5μg/kg/day, i.t. for 21 consecutive days) on aging-induced changes in brain regional (cerebral cortex, hippocampus, hypothalamus and pons-medulla) mitochondrial monoamine oxidase-A (MAO-A) activity with its kinetic parameters. The results of the present study are: (1) The brain regional mitochondrial MAO-A activity and their kinetic parameters (except in Km of pons-medulla) were significantly increased with the increase of age (4-24 months), (2) Aging-induced increase of brain regional MAO-A activity including its Vmax were attenuated with higher dosages of carnosine (1.0-2.5μg/kg/day) and restored toward the activity that observed in young, though its lower dosage (0.5μg/kg/day) were ineffective in these brain regional MAO-A activity, (3) Carnosine at higher dosage in young rats, unlike aged rats significantly inhibited all the brain regional MAO-A activity by reducing their only Vmax excepting cerebral cortex, where Km was also significantly enhanced. These results suggest that carnosine attenuated the aging-induced increase of brain regional MAO-A activity by attenuating its kinetic parameters and restored toward the results of MAO-A activity that observed in corresponding brain regions of young rats.

  7. Potent and Selective Monoamine Oxidase-B Inhibitory Activity: Fluoro- vs. Trifluoromethyl-4-hydroxylated Chalcone Derivatives.

    Science.gov (United States)

    Mathew, Bijo; Mathew, Githa Elizabeth; Uçar, Gülberk; Baysal, Ipek; Suresh, Jerad; Mathew, Sincy; Haridas, Abitha; Jayaprakash, Venkatesan

    2016-08-01

    For various neurodegenerative disorders like Alzheimer's and Parkinson's diseases, selective and reversible MAO-B inhibitors have a great therapeutic value. In our previous study, we have shown that a series of methoxylated chalcones with F functional group exhibited high binding affinity toward human monoamine oxidase-B (hMAO-B). In continuation of our earlier study and to extend the understanding of the structure-activity relationships, a series of five new chalcones were studied for their inhibition of hMAO. The results demonstrated that these compounds are reversible and selective hMAO-B inhibitors with a competitive mode of inhibition. The most active compound, (2E)-1-(4-hydroxyphenyl)-3-[4-(trifluoromethyl)phenyl]prop-2-en-1-one, exhibited a Ki value of 0.33 ± 0.01 μm toward hMAO-B with a selectivity index of 26.36. A molecular docking study revealed that the presence of a H-bond network in hydroxylated chalcone with the N(5) atom of FAD is crucial for MAO-B selectivity and potency.

  8. Comparison of the Inhibition of Monoamine Oxidase and Butyrylcholinesterase Activities by Infusions from Green Tea and Some Citrus Peels

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    Ayokunle O. Ademosun

    2014-01-01

    Full Text Available This study sought to investigate the effect of infusions from green tea (Camellia sinensis and some citrus peels [shaddock (Citrus maxima, grapefruit (Citrus paradisi, and orange (Citrus sinensis] on key enzymes relevant to the management of neurodegenerative conditions [monoamine oxidase (MAO and butyrylcholinesterase (BChE]. The total phenol contents and antioxidant activities as typified by their 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS radicals scavenging abilities, ferric reducing antioxidant properties, and Fe2+ chelating abilities were also investigated. Green tea had the highest total phenol (43.3 mg/g and total flavonoid (16.4 mg/g contents, when compared to orange [total phenol (19.6 mg/g, total flavonoid (6.5 mg/g], shaddock [total phenol (16.3 mg/g, total flavonoid (5.2 mg/g], and grapefruit [total phenol (17.7 mg/g, total flavonoid (5.9 mg/g]. Orange (EC50 = 1.78 mg/mL had the highest MAO inhibitory ability, while green tea had the least MAO inhibitory ability (EC50 = 2.56 mg/mL. Similarly, green tea had the least BChE inhibitory ability (EC50 = 5.43 mg/mL when compared to the citrus peels’ infusions. However, green tea infusions had the strongest highest ABTS radical scavenging ability, reducing power, and Fe2+ chelating ability. The inhibition of MAO and BChE activities by the green tea and citrus peels infusions could make them good dietary means for the prevention/management of neurodegenerative conditions.

  9. Monoamine oxidase A polymorphism moderates stability of attention problems and susceptibility to life stress during adolescence.

    Science.gov (United States)

    Zohsel, K; Bianchi, V; Mascheretti, S; Hohm, E; Schmidt, M H; Esser, G; Brandeis, D; Banaschewski, T; Nobile, M; Laucht, M

    2015-11-01

    Attention problems affect a substantial number of children and adolescents and are predictive of academic underachievement and lower global adaptive functioning. Considerable variability has been observed with regard to the individual development of attention problems over time. In particular, the period of adolescence is characterized by substantial maturation of executive functioning including attentional processing, with the influence of genetic and environmental factors on individual trajectories not yet well understood. In the present investigation, we evaluated whether the monoamine oxidase A functional promoter polymorphism, MAOA-LPR, plays a role in determining continuity of parent-rated attention problems during adolescence. At the same time, a potential effect of severe life events (SLEs) was taken into account. A multi-group path analysis was used in a sample of 234 adolescents (149 males, 85 females) who took part in an epidemiological cohort study at the ages of 11 and 15 years. Attention problems during early adolescence were found to be a strong predictor of attention problems in middle adolescence. However, in carriers of the MAOA-LPR low-activity variant (MAOA-L), stability was found to be significantly higher than in carriers of the high-activity variant (MAOA-H). Additionally, only in MAOA-L carriers did SLEs during adolescence significantly impact on attention problems at the age of 15 years, implying a possible gene × environment interaction. To conclude, we found evidence that attention problems during adolescence in carriers of the MAOA-L allele are particularly stable and malleable to life stressors. The present results underline the usefulness of applying a more dynamic GxE perspective. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  10. Evaluation of the Inhibitory Effects of Bavachinin and Bavachin on Human Monoamine Oxidases A and B

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    Najla O. Zarmouh

    2015-01-01

    Full Text Available Monoamine oxidase B inhibitors (MAO-BIs are used in the early management of Parkinson’s disease (PD. Long-term suspected side effects of MAO-B classical inhibitors established the need for safer alternative therapeutic agents. In our study, the flavanone bavachinin (BNN and its analog bavachin (BVN found in the seeds of Psoralea corylifolia L. ethanolic extract (PCSEE were investigated for their human MAO-A and MAO-B (hMAO-A and hMAO-B inhibition. Both PCSEE and BNN effectively reduced hMAO-B activity more than hMAO-A while BVN had activating effects. BNN showed selective hMAO-B inhibition (IC50 ~ 8.82 μM more than hMAO-A (IC502009;~ 189.28 μM. BNN in the crude extract was determined by HPLC, also validated by TLC showing a yield of 0.21% PCSEE dry weight. BNN competitively inhibited hMAO-A and hMAO-B, with a lower hMAO-B Ki than hMAO-A Ki by 10.33-fold, and reduced hMAO-B Km/Vmax efficiency ratio to be comparable to the standard selegiline. Molecular docking examination of BNN and BVN predicted an indirect role of BNN C7-methoxy group for its higher affinity, selectivity, and reversibility as an MAO-BI. These findings suggest that BNN, which is known to be a potent PPAR-γ agonist, is a selective and competitive hMAO-B inhibitor and could be used in the management of PD.

  11. Sudden infant death syndrome (SIDS) and polymorphisms in Monoamine oxidase A gene (MAOA): a revisit.

    Science.gov (United States)

    Groß, Maximilian; Bajanowski, Thomas; Vennemann, Mechtild; Poetsch, Micaela

    2014-01-01

    Literature describes multiple possible links between genetic variations in the neuroadrenergic system and the occurrence of sudden infant death syndrome. The X-chromosomal Monoamine oxidase A (MAOA) is one of the genes with regulatory activity in the noradrenergic and serotonergic neuronal systems and a polymorphism of the promoter which affects the activity of this gene has been proclaimed to contribute significantly to the prevalence of sudden infant death syndrome (SIDS) in three studies from 2009, 2012 and 2013. However, these studies described different significant correlations regarding gender or age of children. Since several studies, suggesting associations between genetic variations and SIDS, were disproved by follow-up analysis, this study was conducted to take a closer look at the MAOA gene and its polymorphisms. The functional MAOA promoter length polymorphism was investigated in 261 SIDS cases and 93 control subjects. Moreover, the allele distribution of 12 coding and non-coding single nucleotide polymorphisms (SNPs) of the MAOA gene was examined in 285 SIDS cases and 93 controls by a minisequencing technique. In contrast to prior studies with fewer individuals, no significant correlations between the occurrence of SIDS and the frequency of allele variants of the promoter polymorphism could be demonstrated, even including the results from the abovementioned previous studies. Regarding the SNPs, three statistically significant associations were observed which had not been described before. This study clearly disproves interactions between MAOA promoter polymorphisms and SIDS, even if variations in single nucleotide polymorphisms of MAOA should be subjected to further analysis to clarify their impact on SIDS.

  12. Intoxications with the monoamine oxidase inhibitor tranylcypromine: an analysis of fatal and non-fatal events.

    Science.gov (United States)

    Gahr, Maximilian; Schönfeldt-Lecuona, Carlos; Kölle, Markus A; Freudenmann, Roland W

    2013-11-01

    Tranylcypromine (TCP) is a non-selective and irreversible monoamine oxidase inhibitor and an effective agent in the treatment of major depression. It features a complex pharmacologic profile and overdoses might induce severe intoxications. To identify typical clinical presentations of TCP-intoxications, range of associated TCP-dosages and possible differences between fatal and non-fatal intoxications a systematic review of all previously published cases of TCP-intoxications was conducted. We detected n=20 reports of TCP-intoxications in the literature (fatalities n=10). Mean age was 36.7 years (median 37); the majority of patients were female (60%). Frequent findings in patients with TCP-intoxications were disturbance of consciousness/cognitive dysfunction (90%), cardio-vascular symptoms (55%), hyperthermia (50%), respiratory distress (45%), delirium (45%), muscular rigidity (30%) and renal failure (20%). Suicidal intent was present in n=18 (90%) patients. First clinical symptoms related to TCP-intoxication developed on average in less than 1 day. The average dosage related to TCP-intoxication was 677 mg. The highest survived TCP-dosage was 4000 mg and the lowest fatal dosage was 170 mg. Patients with fatal intoxications were on average older (40.5 vs. 32.8 years) and developed a more rapid onset of symptoms (0.2 vs. 0.8 days). Death occurred after a mean time of 0.6 days; symptom relief in patients with non-fatal intoxications developed on average after 3.2 days. Considering the large dose spectrum between survived and lethal TCP-dosages individual susceptibility factors might play a role regarding the severity of clinical symptoms independently of the ingested dosage.

  13. Causality pattern of the blood lead, monoamine oxidase A, and serotonin levels in brass home industry workers chronically exposed to lead

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    Aditya Marianti

    2016-04-01

    Full Text Available The present study aims to analyse the effects of lead (Pb chronic exposure on blood lead levels, Monoamine oxidase A enzyme (MAO A and serotonin levels of brass craftsmen in Pati, Central Java, Indonesia, and to examine the connections among these three variables. The brass home industry area was polluted by lead. Thus, it chronically exposes the workers to lead pollution. Therefore, their blood lead level increased and later raised the level of MAO A and reduced the level of serotonin. Path analysis results show that the path coefficient (ñ of lead effects in decreasing serotonin through MAO A pathway is -0.411. Furthermore, lead effects that directly affect serotonin level without passing through MAO A pathway is -0.391 with residual coefficient (e of 0.572. In conclusion, the increase of blood lead level causes an increase in level of MAO A and drop in the level of serotonin.

  14. Monoamine Oxidases as Potential Contributors to Oxidative Stress in Diabetes: Time for a Study in Patients Undergoing Heart Surgery

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    Oana M. Duicu

    2015-01-01

    Full Text Available Oxidative stress is a pathomechanism causally linked to the progression of chronic cardiovascular diseases and diabetes. Mitochondria have emerged as the most relevant source of reactive oxygen species, the major culprit being classically considered the respiratory chain at the inner mitochondrial membrane. In the past decade, several experimental studies unequivocally demonstrated the contribution of monoamine oxidases (MAOs at the outer mitochondrial membrane to the maladaptative ventricular hypertrophy and endothelial dysfunction. This paper addresses the contribution of mitochondrial dysfunction to the pathogenesis of heart failure and diabetes together with the mounting evidence for an emerging role of MAO inhibition as putative cardioprotective strategy in both conditions.

  15. [Association between the canine monoamine oxidase B (MAOB) gene polymorphisms and behavior of puppies in open-field test].

    Science.gov (United States)

    Li, Xiao-Hui; Xu, Han-Kun; Mao, Da-Gan; Ma, Da-Jun; Chen, Peng; Yang, Li-Guo

    2006-11-01

    Excitability, activity and exploration behavior of puppies in a novel open-field were tested in a total of 204 two-month-old German shepherd dog, labrador retriever or English springer spaniel puppies. The polymorphisms of monoamine oxidase B gene (MAOB) were detected by PCR-RFLP. Statistics analysis indicated that genotype and allele frequencies of the polymorphisms were significantly different among three breeds (P open-field test. The results showed that MAOB gene polymorphisms had a significant effect on walking time, squares crossed, lying time, the times of standing up against walls(P open-field test and TT genotype has favorable effects in these behavior traits.

  16. Natural Products Screening for the Identification of Selective Monoamine Oxidase-B Inhibitors

    Science.gov (United States)

    Zarmouh, Najla O.; Messeha, Samia S.; Elshami, Faisel M.; Soliman, Karam F. A.

    2016-01-01

    Aims Monoamine oxidase-B inhibitors (MAO-BIs) are used for the initial therapy of Parkinson’s disease. Also, MAO-BIs have shown to be effective neuroprotective agents in several neurodegenerative diseases. However, some concerns exist regarding the long-term use of these compounds. Meanwhile, natural compounds showed potential MAO-B selective inhibitions. To date, few selective natural MAO-BIs have been identified. Therefore, the current study is designed to identify plants with potent and specific MAO-B inhibition. Study Design In this work, we utilized high throughput screening to evaluate the different plants ethanolic extract for their effectiveness to inhibit recombinant human (h)MAO-A and hMAO-B and to determine the relative selectivity of the top MAO-BI. Methodology Recombinant human isozymes were verified by Western blotting, and the 155 plants were screened. A continuous fluorometric screening assay was performed followed by two separate hMAO-A and hMAO-B microtiter screenings and IC50 determinations for the top extracts. Results In the screened plants, 9% of the extracts showed more than 1.5-fold relative inhibition of hMAO-B (RIB) and another 9% showed more than 1.5-fold relative inhibition of hMAO-A. The top extracts with the most potent RIBs were Psoralea corylifolia seeds, Phellodendron amurense bark, Glycyrrhiza uralensis roots, and Ferula assafoetida roots, with the highest RIB of 5.9-fold. Furthermore, extensive maceration of the promising extracts led to increase inhibitory effects with a preserved RIB as confirmed with luminescence assay. The top four extracts hMAO-BIs were equally potent (IC50= 1.3 to 3.8 μg/mL) with highly significant relative selectivities to inhibit hMAO-B (4.1- to 13.4-fold). Conclusion The obtained results indicate that Psoralea corylifolia seeds, Ferula assafoetida, Glycyrrhiza uralensis roots, and Phellodendron amurense ethanolic extracts have selective inhibitions for human MAO-B. Investigating these plant extracts as

  17. Flavonoids from Sideritis Species: Human Monoamine Oxidase (hMAO Inhibitory Activities, Molecular Docking Studies and Crystal Structure of Xanthomicrol

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    Fatma Pinar Turkmenoglu

    2015-04-01

    Full Text Available The inhibitory effects of flavonoids on monoamine oxidases (MAOs have attracted great interest since alterations in monoaminergic transmission are reported to be related to neurodegenerative diseases such as Parkinson’s and Alzheimer’s diseases and psychiatric disorders such as depression and anxiety, thus MAOs may be considered as targets for the treatment of these multi-factorial diseases. In the present study, four Sideritis flavonoids, xanthomicrol (1, isoscutellarein 7-O-[6'''-O-acetyl-β-D-allopyranosyl-(1→2]-β-D-glucopyranoside (2, isoscutellarein 7-O-[6'''-O-acetyl-β-D-allopyranosyl-(1→2]-6''-O-acetyl-β-D-glucopyranoside (3 and salvigenin (4 were docked computationally into the active site of the human monoamine oxidase isoforms (hMAO-A and hMAO-B and were also investigated for their hMAO inhibitory potencies using recombinant hMAO isoenzymes. The flavonoids inhibited hMAO-A selectively and reversibly in a competitive mode. Salvigenin (4 was found to be the most potent hMAO-A inhibitor, while xanthomicrol (1 appeared as the most selective hMAO-A inhibitor. The computationally obtained results were in good agreement with the corresponding experimental values. In addition, the x-ray structure of xanthomicrol (1 has been shown. The current work warrants further preclinical studies to assess the potential of xanthomicrol (1 and salvigenin (4 as new selective and reversible hMAO-A inhibitors for the treatment of depression and anxiety.

  18. The structure of monoamine oxidase from Aspergillus niger provides a molecular context for improvements in activity obtained by directed evolution.

    Science.gov (United States)

    Atkin, Kate E; Reiss, Renate; Koehler, Valentin; Bailey, Kevin R; Hart, Sam; Turkenburg, Johan P; Turner, Nicholas J; Brzozowski, A Marek; Grogan, Gideon

    2008-12-31

    Monoamine oxidase from Aspergillus niger (MAO-N) is a flavoenzyme that catalyses the oxidative deamination of primary amines. MAO-N has been used as the starting model for a series of directed evolution experiments, resulting in mutants of improved activity and broader substrate specificity, suitable for application in the preparative deracemisation of primary, secondary and tertiary amines when used as part of a chemoenzymatic oxidation-reduction cycle. The structures of a three-point mutant (Asn336Ser/Met348Lys/Ile246Met or MAO-N-D3) and a five-point mutant (Asn336Ser/Met348Lys/Ile246Met/Thr384Asn/Asp385Ser or MAO-N-D5) have been obtained using a multiple-wavelength anomalous diffraction experiment on a selenomethionine derivative of the truncated MAO-N-D5 enzyme. MAO-N exists as a homotetramer with a large channel at its centre and shares some structural features with human MAO B (MAO-B). A hydrophobic cavity extends from the protein surface to the active site, where a non-covalently bound flavin adenine dinucleotide (FAD) sits at the base of an 'aromatic cage,' the sides of which are formed by Trp430 and Phe466. A molecule of l-proline was observed near the FAD, and this ligand superimposed well with isatin, a reversible inhibitor of MAO-B, when the structures of MAO-N proline and MAO-B-isatin were overlaid. Of the mutations that confer the ability to catalyse the oxidation of secondary amines in MAO-N-D3, Asn336Ser reduces steric bulk behind Trp430 of the aromatic cage and Ile246Met confers greater flexibility within the substrate binding site. The two additional mutations, Thr384Asn and Asp385Ser, that occur in the MAO-N-D5 variant, which is able to oxidise tertiary amines, appear to influence the active-site environment remotely through changes in tertiary structure that perturb the side chain of Phe382, again altering the steric and electronic character of the active site near FAD. The possible implications of the change in steric and electronic environment

  19. Biogenic aldehyde(s) derived from the action of monoamine oxidase may mediate the antidipsotropic effect of daidzin.

    Science.gov (United States)

    Keung, W M

    2001-01-30

    Daidzin, a major active principle of an ancient herbal treatment for 'alcohol addiction', was first shown to suppress ethanol intake in Syrian golden hamsters. Since then this activity has been confirmed in Wistar rats, Fawn hooded rats, genetically bred alcohol preferring P rats and African green moneys under various experimental conditions, including two-level operant, two-bottle free-choice, limited access, and alcohol-deprivation paradigms. In vitro, daidzin is a potent and selective inhibitor of mitochondrial aldehyde dehydrogenase (ALDH-2). However, in vivo, it does not affect overall acetaldehyde metabolism in golden hamsters. Using isolated hamster liver mitochondria and 5-hydroxytryptamine (5-HT) and dopamine (DA) as the substrates, we demonstrated that daidzin inhibits the second but not the first step of the MAO/ALDH-2 pathway, the major pathway that catalyzes monoamine metabolism in mitochondria. Correlation studies using structural analogs of daidzin led to the hypothesis that the mitochondrial MAO/ALDH-2 pathway may be the site of action of daidzin and that one or more biogenic aldehydes such as 5-hydroxyindole-3-acetaldehyde (5-HIAL) and/or DOPAL derived from the action of monoamine oxidase (MAO) may be mediators of its antidipsotropic action.

  20. Inhibition of Excessive Monoamine Oxidase A/B Activity Protects Against Stress-induced Neuronal Death in Huntington Disease.

    Science.gov (United States)

    Ooi, Jolene; Hayden, Michael R; Pouladi, Mahmoud A

    2015-12-01

    Monoamine oxidases (MAO) are important components of the homeostatic machinery that maintains the levels of monoamine neurotransmitters, including dopamine, in balance. Given the imbalance in dopamine levels observed in Huntington disease (HD), the aim of this study was to examine MAO activity in a mouse striatal cell model of HD and in human neural cells differentiated from control and HD patient-derived induced pluripotent stem cell (hiPSC) lines. We show that mouse striatal neural cells expressing mutant huntingtin (HTT) exhibit increased MAO expression and activity. We demonstrate using luciferase promoter assays that the increased MAO expression reflects enhanced epigenetic activation in striatal neural cells expressing mutant HTT. Using cellular stress paradigms, we further demonstrate that the increase in MAO activity in mutant striatal neural cells is accompanied by enhanced susceptibility to oxidative stress and impaired viability. Treatment of mutant striatal neural cells with MAO inhibitors ameliorated oxidative stress and improved cellular viability. Finally, we demonstrate that human HD neural cells exhibit increased MAO-A and MAO-B expression and activity. Altogether, this study demonstrates abnormal MAO expression and activity and suggests a potential use for MAO inhibitors in HD.

  1. Hydralazine is involved in tele-methylhistamine metabolism by inhibiting monoamine oxidase B in pregnancy-associated hypertensive mice.

    Science.gov (United States)

    Kawasaki, Shohei; Kako, Koichiro; Nagashima, Yusuke; Kanou, Akihiko; Ishida, Junji; Fukamizu, Akiyoshi

    2017-01-07

    Hypertensive disorders of pregnancy globally affect 6-8% of gestation and remain a major cause of both foetal and maternal morbidity and mortality. However, the antihypertensive medications for the patients of this disease are strictly limited due to the teratogenic potentials. Here, we found that tele-methylhistamine (tMH) increased in response to the administration of hydralazine (Hdz), a vasodilative agent, in the pregnancy-associated hypertensive (PAH) mice. Hdz abrogated the degradation of tMH catalyzed by monoamine oxidase B (MAO-B) in vitro These results suggested that Hdz inhibited the MAO-B activity and consequently tMH increased in the maternal circulation of PAH mice.

  2. Cerebral monoamine oxidase A inhibition in tobacco smokers confirmed with PET and [{sup 11}C]Befloxatone

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, C.; Bragulat, V.; Penttila, J.; Artiges, E.; Martinot, J.L.; Trichard, Ch. [INSERM U797, Research Unit ' Neuroimaging and Psychiatry' , Orsay (France); Leroy, C.; Bragulat, V.; Penttila, J.; Artiges, E.; Martinot, J.L.; Trichard, Ch. [CEA, ' Neuroimaging and Psychiatry, U797 Unit, Hospital Department Frederic Joliot and Neurospin (France); Leroy, C.; Bragulat, V.; Penttila, J.; Artiges, E.; Martinot, J.L.; Trichard, Ch. [Paris sud University - Paris Descartes University, UMR U797 (France); Berlin, I. [Service de Pharmacologie, Hopital Pitie-Salpetriere - Universite Paris6 - INSERM U677, Paris (France); Gregoire, M.C.; Bottlaender, M.; Roumenov, D.; Dolle, F.; Bourgeois, S. [CEA, DSV, I2BM, Service Hospitalier Frederic Joliot, Orsay (France); Artiges, E.; Trichard, Ch. [Psychiatry Department, Orsay Hospital, Orsay (France)

    2009-07-01

    The inhibition of cerebral monoamine oxidases (MAOs) by cigarette smoke components could participate to the tobacco addiction. However, the actual extent of this inhibition in vivo in smokers is still poorly known. We investigated cerebral MAO-A availability in 7 tobacco-dependent subjects and 6 healthy nonsmokers, using positron emission tomography (PET) and the MAO-A selective radioligand [{sup 11}C]befloxatone. In comparison to nonsmokers, smokers showed a significant overall reduction of [{sup 11}C]befloxatone binding potential (BP) in cortical areas (average reduction, -60%) and a similar trend in caudate and thalamus (-40%). Our findings confirm a widespread inhibition of cerebral MAO-A in smokers. This mechanism may contribute to tobacco addiction and for a possible mood-modulating effect of tobacco. (authors)

  3. Synthesis and characterization of [{sup 125}I]N-(2-aminoethyl)-4-iodobenzamide as a selective monoamine oxidase B inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Rafii, Hamid; Chalon, Sylvie; Ombetta, Jean-Edouard; Frangin, Yves; Garreau, Lucette; Dognon, Anne-Marie; Lena, Isabelle; Bodard, Sylvie; Vilar, Marie-Paule; Besnard, Jean-Claude; Guilloteau, Denis

    1995-07-01

    We described the radiosynthesis of an analog of Ro 16-6491, [{sup 125}I]N-(2-aminoethyl)-4-iodobenzamide, for SPECT exploration of the monoamine oxidase B (MAO-B) in human brain. The radiolabelling was carried out by nucleophilic exchange of the brominated precursor at solid-state phase in presence of ammonium sulphate. The radiochemical purity of radioiodinated product was higher than 95%. In comparison with Ro 16-6491, the in vitro studies showed a good selectivity of stable N-(2-aminoethyl)-4-iodobenzamide for MAO-B but a slightly lower affinity. Biodistribution studies in the rat showed a high and selective uptake of this compound in the pineal gland 1 h after i.v. injection. The cerebral uptake was low, but the coupling of [{sup 125}I]N-(2-aminoethyl)-4-iodobenzamide with a lipophilic radical to enhance the passage through the blood-brain barrier can be envisaged.

  4. Synthesis and monoamine oxidase inhibitory activities of some 3-(4-fluorophenyl)-5-aryl-n-substituted-4,5-dihydro-(1H)-pyrazole-1-carbothioamide derivatives.

    Science.gov (United States)

    Koç, G Ş; Tan, O U; Uçar, G; Yildirim, E; Erol, K; Palaska, E

    2014-11-01

    28 new 3-(4-fluorophenyl)-5-aryl-N-substituted-4,5-dihydro-1H-pyrazole-1-carbothioamide derivatives were synthesized and evaluated in vitro for their monoamine oxidase (MAO) A and B inhibitory activity and selectivity. The derivatives substituted by halogen on the fifth position of pyrazole ring, inhibited MAO-A enzyme with a high selectivity index. On the other hand, compounds substituted with 2-naphthyl inhibited MAO-B enzyme with a moderate selectivity index. Docking studies were done to highlight the interactions of the most active derivative with the active site of MAO-A. In addition, in vivo antidepressant and anxiolytic activities of the compounds having selective MAO-A inhibitory effects, were investigated by using Porsolt forced swimming and elevated plus-maze tests respectively. 3-(4-Fluorophenyl)-5-(4-chloro-phenyl)-N-allyl-4,5-dihydro-1H-pyrazole-1-carbothio-amide has antidepressant, 3-(4-fluorophenyl)-5-(4-chlorophenyl)-N-methyl-4,5-dihydro-1H-pyrazole-1-carbothioamide and 3-(4-fluoro-phenyl)-5-(4-bromophenyl)-N-ethyl-4,5-dihydro-1H-pyrazole-1-carbothioamide have anxiolytic activity.

  5. Apple fruit copper amine oxidase isoforms: peroxisomal MdAO1 prefers diamines as substrates, whereas extracellular MdAO2 exclusively utilizes monoamines.

    Science.gov (United States)

    Zarei, Adel; Trobacher, Christopher P; Cooke, Alison R; Meyers, Ashley J; Hall, J Christopher; Shelp, Barry J

    2015-01-01

    4-Aminobutyrate (GABA) accumulates in apple fruit during controlled atmosphere storage. A potential source of GABA is the polyamine putrescine, which can be oxidized via copper-containing amine oxidase (CuAO), resulting in the production 4-aminobutanal/Δ(1)-pyrroline, with the consumption of O2 and release of H2O2 and ammonia. Five putative CuAO genes (MdAO genes) were cloned from apple (Malus domestica Borkh. cv. Empire) fruit, and the deduced amino acid sequences found to contain the active sites typically conserved in CuAOs. Genes encoding two of these enzymes, MdAO1 and MdAO2, were highly expressed in apple fruit and selected for further analysis. Amino acid sequence analysis predicted the presence of a C-terminal peroxisomal targeting signal 1 tripeptide in MdAO1 and an N-terminal signal peptide and N-glycosylation site in MdAO2. Transient expression of green fluorescent fusion proteins in Arabidopsis protoplasts or onion epidermal cells revealed a peroxisomal localization for MdAO1 and an extracellular localization for MdAO2. The enzymatic activities of purified recombinant MdAO1 and MdAO2 were measured continuously as H2O2 production using a coupled reaction. MdAO1 did not use monoamines or polyamines and displayed high catalytic efficiency for 1,3-diaminopropane, putrescine and cadaverine, whereas MdAO2 exclusively utilized aliphatic and aromatic monoamines, including 2-phenylethylamine and tyramine. Together, these results indicate that MdAO1 may contribute to GABA production via putrescine oxidation in the peroxisome of apple fruit under controlled atmosphere conditions. MdAO2 seems to be involved in deamination of 2-phenylethylamine, which is a step in the biosynthesis of 2-phenylethanol, a contributor to fruit flavor and flower fragrance.

  6. Association between monoamine oxidase A gene promoter 30 bp repeat polymorphism and tardive dyskinesia in Chinese schizophrenics

    Institute of Scientific and Technical Information of China (English)

    Changhe Fan; Lihua Li; Yan Fu; Hehuang Deng; Xiangjiao Liao; Youcai Zhou

    2006-01-01

    BACKGROUND: The pathophysiology of tardive dyskinesia (TD) is not yet fully understood. With the hypothesis of altered dopaminergic neurotransmission, altered activities of dopamine degrading enzymes such as monoamine oxidase A (MAOA) and their coding genes are supposed to be related to the pathophysiology of TD.OBJECTIVE: To investigate possible association between 30 bp variable number tandem repeat (VNTR) polymorphism in the promoter of MAOA gene and susceptibility, severity of neuroleptic induced TD in Chinese Han people in Guandong Province.DESIGN: Non-randomization-synchronization controlled study. SETTING: Guangdong Mental Health Institute, Guangdong Provincial People's Hospital; Guangzhou Psychiatric Hospital; Affiliated Psychiatric Hospital of Guangzhou Municipal Bureau of Civil Administration. PARTICIPANTS: A total of 179 subjects were enrolled in the study. All subjects were sporadic and genetically unrelated Chinese schizophrenic patients who were hospitalizing in Guangzhou Psychiatric Hospital or Affiliated Psychiatric Hospital of Guangzhou Municipal Bureau of Civil Administration during January to April 2005. The diagnosis of schizophrenia was made according to the criteria of Diagnostic and Statistic Manual of Mental Disorder-the third edition-revised (DSM-Ⅲ-R). Among all patients, 88 were diagnosed as with TD and 91 without TD according to the research diagnostic criteria described by Schooler-Kane. Informed consent was obtained from all subjects or their relatives.METHODS: ① TD severity was assessed with the AIMS which was a 5-degree rating scale from 0 to 4 (corresponding to none, minimal, mild, moderate and severe, respectively). The study was approved by the Ethics Committees of the two hospitals and informed consent was obtained from all subjects or their relatives. ② The polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis (PAGE) techniques were used to detect MAOA gene 30 bp VNTR polymorphism in schizophrenic patients

  7. Calcium-sensitive regulation of monoamine oxidase-A contributes to the production of peroxyradicals in hippocampal cultures: implications for Alzheimer disease-related pathology

    Directory of Open Access Journals (Sweden)

    Li XinMin

    2007-09-01

    Full Text Available Abstract Background Calcium (Ca2+ has recently been shown to selectively increase the activity of monoamine oxidase-A (MAO-A, a mitochondria-bound enzyme that generates peroxyradicals as a natural by-product of the deamination of neurotransmitters such as serotonin. It has also been suggested that increased intracellular free Ca2+ levels as well as MAO-A may be contributing to the oxidative stress associated with Alzheimer disease (AD. Results Incubation with Ca2+ selectively increases MAO-A enzymatic activity in protein extracts from mouse hippocampal HT-22 cell cultures. Treatment of HT-22 cultures with the Ca2+ ionophore A23187 also increases MAO-A activity, whereas overexpression of calbindin-D28K (CB-28K, a Ca2+-binding protein in brain that is greatly reduced in AD, decreases MAO-A activity. The effects of A23187 and CB-28K are both independent of any change in MAO-A protein or gene expression. The toxicity (via production of peroxyradicals and/or chromatin condensation associated with either A23187 or the AD-related β-amyloid peptide, which also increases free intracellular Ca2+, is attenuated by MAO-A inhibition in HT-22 cells as well as in primary hippocampal cultures. Conclusion These data suggest that increases in intracellular Ca2+ availability could contribute to a MAO-A-mediated mechanism with a role in AD-related oxidative stress.

  8. Monoamine Oxidase Inhibitory Constituents of Propolis: Kinetics and Mechanism of Inhibition of Recombinant Human MAO-A and MAO-B

    Directory of Open Access Journals (Sweden)

    Narayan D. Chaurasiya

    2014-11-01

    Full Text Available Propolis is the resinous material that bees gather from leaf buds, flowers and vegetables. Propolis extracts contain constituents with a broad spectra of pharmacological properties and are important ingredients of popular dietary supplements. Propolis extracts were evaluated in vitro for inhibition of recombinant human monoamine oxidase (MAO-A and MAO-B. The dichloromethane extract of propolis showed potent inhibition of human MAO-A and MAO-B. Further fractionation identified the most active fractions as rich in flavonoids. Galangin and apigenin were identified as the principal MAO-inhibitory constituents. Inhibition of MAO-A by galangin was about 36 times more selective than MAO-B, while apigenin selectivity for MAO-A vs. MAO-B was about 1.7 fold. Apigenin inhibited MAO-B significantly more potently than galangin. Galangin and apigenin were further evaluated for kinetic characteristics and the mechanism for the enzymes’ inhibition. Binding of galangin and apigenin with MAO-A and -B was not time-dependent and was reversible, as suggested by enzyme-inhibitor binding and dissociation-dialysis assay. The inhibition kinetics studies suggested that galangin and apigenin inhibited MAO-A and -B by a competitive mechanism. Presence of prominent MAO inhibitory constituents in propolis products suggests their potential for eliciting pharmacological effects that might be useful in depression or other neurological disorders. The results may also have important implications in drug-dietary supplement interactions.

  9. Correlation between total nitrite/nitrate concentrations and monoamine oxidase (types A and B) and semicarbazide-sensitive amine oxidase enzymatic activities in human mesenteric arteries from non-diabetic and type 2 diabetic patients

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, S.F.; Figueiredo, I.V. [Laboratório de Farmacologia, Faculdade de Farmácia, Universidade de Coimbra, Coimbra (Portugal); Pereira, J.S. [Instituto Português de Oncologia de Coimbra, Coimbra (Portugal); Lopes, M.C.; Caramona, M.M. [Laboratório de Farmacologia, Faculdade de Farmácia, Universidade de Coimbra, Coimbra (Portugal)

    2011-11-25

    The aim of this study was to determine the correlation between total nitrite/nitrate concentrations (NOx) and the kinetic parameters of monoamine oxidase enzymes (MAO-A and MAO-B) and semicarbazide-sensitive amine oxidase (SSAO) in human mesenteric arteries. Arteries were from non-diabetic and type 2 diabetic patients with sigmoid or rectum carcinoma for whom surgery was the first option and who were not exposed to neo-adjuvant therapy. Segments of human inferior mesenteric arteries from non-diabetic (61.1 ± 8.9 years old, 7 males and 5 females, N = 12) and type 2 diabetic patients (65.8 ± 6.2 years old, 8 males and 4 females, N = 12) were used to determine NOx concentrations and the kinetic parameters of MAO-A, MAO-B and SSAO by the Griess reaction and by radiochemical assay, respectively. The NOx concentrations in arteries from diabetic patients did not differ significantly from those of the non-diabetic group (10.28 ± 4.61 vs 10.71 ± 4.32 nmol/mg protein, respectively). In the non-diabetic group, there was a positive correlation between NOx concentrations and MAO-B parameters: K{sub m} (r = 0.612, P = 0.034) and V{sub max} (r = 0.593, P = 0.042), and a negative correlation with the SSAO parameters: K{sub m} (r = -0.625, P = 0.029) and V{sub max} (r = -0.754, P = 0.005). However, in the diabetic group no correlation was found between NOx concentrations and the three kinetic parameters of the enzymes. These results suggest an important function of sympathetic nerves and vascular NOx concentrations in arteries of non-diabetic patients. Thus, these results confirm the importance of a balance between oxidants and antioxidants in the maintenance of vascular homeostasis to prevent oxidative stress.

  10. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis

    NARCIS (Netherlands)

    Kopacz, Malgorzata; Heuts, Dominic P. H. M.; Fraaije, Marco W.

    2014-01-01

    Putrescine oxidase from Rhodococcus erythropolis (PuO) is a flavin-containing amine oxidase from the monoamine oxidase family that performs oxidative deamination of aliphatic diamines. In this study we report pre-steady-state kinetic analyses of the enzyme with the use of single-and double-mixing st

  11. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis

    NARCIS (Netherlands)

    Kopacz, Malgorzata; Heuts, Dominic P. H. M.; Fraaije, Marco W.

    2014-01-01

    Putrescine oxidase from Rhodococcus erythropolis (PuO) is a flavin-containing amine oxidase from the monoamine oxidase family that performs oxidative deamination of aliphatic diamines. In this study we report pre-steady-state kinetic analyses of the enzyme with the use of single-and double-mixing

  12. Combination of polymorphic variants in serotonin transporter and monoamine oxidase-A genes may influence the risk for early-onset alcoholism.

    Science.gov (United States)

    Bordukalo-Niksic, Tatjana; Stefulj, Jasminka; Matosic, Ana; Mokrovic, Gordana; Cicin-Sain, Lipa

    2012-12-30

    The combinatory effect of polymorphisms in serotonin transporter and monoamine oxidase-A genes on the aetiopathogenesis of alcoholism was investigated in a sample of 714 individuals. Increased frequency of subjects having three 'suspected' genotypes (5-HTTLPR-LL, STin2-1010 and MAO-A 3-repeat allele) was found among type-2 alcoholic patients (P=0.0189). Results highlight serotonergic/genetic contribution to early-onset alcoholism.

  13. Behavioral and pharmacokinetic interactions between monoamine oxidase inhibitors and the hallucinogen 5-methoxy-N,N-dimethyltryptamine.

    Science.gov (United States)

    Halberstadt, Adam L

    2016-04-01

    Monoamine oxidase inhibitors (MAOIs) are often ingested together with tryptamine hallucinogens, but relatively little is known about the consequences of their combined use. We have shown previously that monoamine oxidase-A (MAO-A) inhibitors alter the locomotor profile of the hallucinogen 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) in rats, and enhance its interaction with 5-HT2A receptors. The goal of the present studies was to investigate the mechanism for the interaction between 5-MeO-DMT and MAOIs, and to determine whether other behavioral responses to 5-MeO-DMT are similarly affected. Hallucinogens disrupt prepulse inhibition (PPI) in rats, an effect typically mediated by 5-HT2A activation. 5-MeO-DMT also disrupts PPI but the effect is primarily attributable to 5-HT1A activation. The present studies examined whether an MAOI can alter the respective contributions of 5-HT1A and 5-HT2A receptors to the effects of 5-MeO-DMT on PPI. A series of interaction studies using the 5-HT1A antagonist WAY-100,635 and the 5-HT2A antagonist MDL 11,939 were performed to assess the respective contributions of these receptors to the behavioral effects of 5-MeO-DMT in rats pretreated with an MAOI. The effects of MAO-A inhibition on the pharmacokinetics of 5-MeO-DMT and its metabolism to bufotenine were assessed using liquid chromatography-electrospray ionization-selective reaction monitoring-tandem mass spectrometry (LC-ESI-SRM-MS/MS). 5-MeO-DMT (1mg/kg) had no effect on PPI when tested 45-min post-injection but disrupted PPI in animals pretreated with the MAO-A inhibitor clorgyline or the MAO-A/B inhibitor pargyline. The combined effect of 5-MeO-DMT and pargyline on PPI was antagonized by pretreatment with either WAY-100,635 or MDL 11,939. Inhibition of MAO-A increased the level of 5-MeO-DMT in plasma and whole brain, but had no effect on the conversion of 5-MeO-DMT to bufotenine, which was found to be negligible. The present results confirm that 5-MeO-DMT can disrupt PPI by

  14. Behavioral and Pharmacokinetic Interactions Between Monoamine Oxidase Inhibitors and the Hallucinogen 5-Methoxy-N,N-dimethyltryptamine

    Science.gov (United States)

    Halberstadt, Adam L.

    2016-01-01

    Monoamine oxidase inhibitors (MAOIs) are often ingested together with tryptamine hallucinogens, but relatively little is known about the consequences of their combined use. We have shown previously that monoamine oxidase-A (MAO-A) inhibitors alter the locomotor profile of the hallucinogen 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) in rats, and enhance its interaction with 5-HT2A receptors. The goal of the present studies was to investigate the mechanism for the interaction between 5-MeO-DMT and MAOIs, and to determine whether other behavioral responses to 5-MeO-DMT are similarly affected. Hallucinogens disrupt prepulse inhibition (PPI) in rats, an effect typically mediated by 5-HT2A activation. 5-MeO-DMT also disrupts PPI but the effect is primarily attributable to 5-HT1A activation. The present studies examined whether an MAOI can alter the respective contributions of 5-HT1A and 5-HT2A receptors to the effects of 5-MeO-DMT on PPI. A series of interaction studies using the 5-HT1A antagonist WAY-100635 and the 5-HT2A antagonist MDL 11,939 were performed to assess the respective contributions of these receptors to the behavioral effects of 5-MeO-DMT in rats pretreated with an MAOI. The effects of MAO-A inhibition on the pharmacokinetics of 5-MeO-DMT and its metabolism to bufotenine were assessed using liquid chromatography–electrospray ionization–selective reaction monitoring–tandem mass spectrometry (LC-ESI-SRM-MS/MS). 5-MeO-DMT (1 mg/kg) had no effect on PPI when tested 45-min post-injection but disrupted PPI in animals pretreated with the MAO-A inhibitor clorgyline or the MAO-A/B inhibitor pargyline. The combined effect of 5-MeO-DMT and pargyline on PPI was antagonized by pretreatment with either WAY-100635 or MDL 11,939. Inhibition of MAO-A increased the level of 5-MeO-DMT in plasma and whole brain, but had no effect on the conversion of 5-MeO-DMT to bufotenine, which was found to be negligible. The present results confirm that 5-MeO-DMT can disrupt PPI

  15. Scale Alpha and Beta of Quantitative Convergence and Chemical Reactivity Analysis in Dual Cholinesterase/Monoamine Oxidase Inhibitors for the Alzheimer Disease Treatment Using Density Functional Theory (DFT

    Directory of Open Access Journals (Sweden)

    Alejandro Morales-Bayuelo

    2013-01-01

    Full Text Available Molecular quantum similarity descriptors and Density Functional Theory (DFT based reactivity descriptors were studied for a series of cholinesterase/monoamine oxidase inhibitors used for the Alzheimer's disease treatment (AD. This theoretical study is expected to shed some light onto some molecular aspects that could contribute to the knowledge of the molecular mechanics behind interactions of these molecules with acetylcholinesterase (AChE and butyrylcholinesterase (BuChE, as well as with monoamine oxidase (MAO A and B. The Topogeometrical Superposition Algorithm to handle flexible molecules (TGSA-Flex alignment method was used to solve the problem of the relative orientation in the quantum similarity (QS field. Using the molecular quantum similarity (MQS field and reactivity descriptors supported in the DFT was possible the quantification of the steric and electrostatic effects through of the Coulomb and Overlap quantitative convergence scales (alpha and beta. In addition, an analysis of reactivity indexes is development, using global and local descriptors, identifying the binding sites and selectivity in the (cholinesterase/monoamine oxidase inhibitors, understanding the retrodonor process, and showing new insight for drugs design in a disease of difficult control as Alzheimer.

  16. The Influence of Monoamine Oxidase Variants on the Risk of Betel Quid-Associated Oral and Pharyngeal Cancer

    Directory of Open Access Journals (Sweden)

    Ping-Ho Chen

    2014-01-01

    Full Text Available Betel quid (BQ and areca nut (AN (major BQ ingredient are group I human carcinogens illustrated by International Agency for Research on Cancer and are closely associated with an elevated risk of oral potentially malignant disorders (OPMDs and cancers of the oral cavity and pharynx. The primary alkaloid of AN, arecoline, can be metabolized via the monoamine oxidase (MAO gene by inducing reactive oxygen species (ROS. The aim of this study was to investigate whether the variants of the susceptible candidate MAO genes are associated with OPMDs and oral and pharyngeal cancer. A significant trend of MAO-A mRNA expression was found in in vitro studies. Using paired human tissues, we confirmed the significantly decreased expression of MAO-A and MAO-B in cancerous tissues when compared with adjacent noncancerous tissues. Moreover, we determined that MAO-A single nucleotide polymorphism variants are significantly linked with oral and pharyngeal cancer patients in comparison to OPMDs patients [rs5953210 risk G-allele, odds ratio = 1.76; 95% confidence interval = 1.02-3.01]. In conclusion, we suggested that susceptible MAO family variants associated with oral and pharyngeal cancer may be implicated in the modulation of MAO gene activity associated with ROS.

  17. The Influence of Monoamine Oxidase Variants on the Risk of Betel Quid-Associated Oral and Pharyngeal Cancer

    Science.gov (United States)

    Huang, Bin; Shieh, Tien-Yu; Wang, Yan-Hsiung; Chen, Yuk-Kwan; Wu, Ju-Hui; Huang, Jhen-Hao; Chen, Chun-Chia; Lee, Ka-Wo

    2014-01-01

    Betel quid (BQ) and areca nut (AN) (major BQ ingredient) are group I human carcinogens illustrated by International Agency for Research on Cancer and are closely associated with an elevated risk of oral potentially malignant disorders (OPMDs) and cancers of the oral cavity and pharynx. The primary alkaloid of AN, arecoline, can be metabolized via the monoamine oxidase (MAO) gene by inducing reactive oxygen species (ROS). The aim of this study was to investigate whether the variants of the susceptible candidate MAO genes are associated with OPMDs and oral and pharyngeal cancer. A significant trend of MAO-A mRNA expression was found in in vitro studies. Using paired human tissues, we confirmed the significantly decreased expression of MAO-A and MAO-B in cancerous tissues when compared with adjacent noncancerous tissues. Moreover, we determined that MAO-A single nucleotide polymorphism variants are significantly linked with oral and pharyngeal cancer patients in comparison to OPMDs patients [rs5953210 risk G-allele, odds ratio = 1.76; 95% confidence interval = 1.02-3.01]. In conclusion, we suggested that susceptible MAO family variants associated with oral and pharyngeal cancer may be implicated in the modulation of MAO gene activity associated with ROS. PMID:25389533

  18. Predicting drunk driving: contribution of alcohol use and related problems, traffic behaviour, personality and platelet monoamine oxidase (MAO) activity.

    Science.gov (United States)

    Eensoo, Diva; Paaver, Marika; Harro, Maarike; Harro, Jaanus

    2005-01-01

    The aim of the study was to characterize the predictive value of socio-economic data, alcohol consumption measures, smoking, platelet monoamine oxidase (MAO) activity, traffic behaviour habits and impulsivity measures for actual drunk driving. Data were collected from 203 male drunk driving offenders and 211 control subjects using self-reported questionnaires, and blood samples were obtained from the two groups. We identified the combination of variables, which predicted correctly, approximately 80% of the subjects' belonging to the drunk driving and control groups. Significant independent discriminators in the final model were, among the health-behaviour measures, alcohol-related problems, frequency of using alcohol, the amount of alcohol consumed and smoking. Predictive traffic behaviour measures were seat belt use and paying for parking. Among the impulsivity measures, dysfunctional impulsivity was the best predictor; platelet MAO activity and age also had an independent predictive value. Our results support the notion that drunk driving is the result of a combination of various behavioural, biological and personality-related risk factors.

  19. Gene-Gene-Environment Interactions of Serotonin Transporter, Monoamine Oxidase A and Childhood Maltreatment Predict Aggressive Behavior in Chinese Adolescents

    Science.gov (United States)

    Zhang, Yun; Ming, Qing-sen; Yi, Jin-yao; Wang, Xiang; Chai, Qiao-lian; Yao, Shu-qiao

    2017-01-01

    Gene-environment interactions that moderate aggressive behavior have been identified independently in the serotonin transporter (5-HTT) gene and monoamine oxidase A gene (MAOA). The aim of the present study was to investigate epistasis interactions between MAOA-variable number tandem repeat (VNTR), 5-HTTlinked polymorphism (LPR) and child abuse and the effects of these on aggressive tendencies in a group of otherwise healthy adolescents. A group of 546 Chinese male adolescents completed the Child Trauma Questionnaire and Youth self-report of the Child Behavior Checklist. Buccal cells were collected for DNA analysis. The effects of childhood abuse, MAOA-VNTR, 5-HTTLPR genotypes and their interactive gene-gene-environmental effects on aggressive behavior were analyzed using a linear regression model. The effect of child maltreatment was significant, and a three-way interaction among MAOA-VNTR, 5-HTTLPR and sexual abuse (SA) relating to aggressive behaviors was identified. Chinese male adolescents with high expression of the MAOA-VNTR allele and 5-HTTLPR “SS” genotype exhibited the highest aggression tendencies with an increase in SA during childhood. The findings reported support aggression being a complex behavior involving the synergistic effects of gene-gene-environment interactions. PMID:28203149

  20. Therapeutic applications of selective and non-selective inhibitors of monoamine oxidase A and B that do not cause significant tyramine potentiation.

    Science.gov (United States)

    Youdim, Moussa B H; Weinstock, Marta

    2004-01-01

    The major side effect with the use of first generation of non selective monoamine oxidase (MAO) inhibitors as neuropsychiatric drugs was what became known as the "cheese reaction". Namely, potentiation of sympathomimetic activity of ingested tyramine present in cheese and other food stuff, resulting from its ability to release noradrenaline, when prevented from metabolism by MAO. The identification of two forms of MAO, termed types A and B and their selective irreversible inhibitors resolved some of this problems. However irreversible MAO-A inhibitors continue to induce a cheese reaction, whereas MAO-B inhibitors at their selective dosage did not and led to introduction of L-deprenyl (selegiline) as an anti-Parkinson drug, since dopamine is equally well metabolized by both enzyme forms. The cheese reaction is a consequence of inhibition of MAO-A, the enzyme responsible for metabolism of noradrenaline and serotonin, located in peripheral adrenergic neurons. The consequence of these findings were the development of reversible MAO-A inhibitors (RIMA), moclobemide and brofaromin, as antidepressants and possible anti-Parkinson activity, with limited tyramine potentiation, since the amine can displace the inhibitor from its binding site on the enzyme. It has always been deemed a greater pharmacological advantage to inhibit both forms of the enzymes to get the full functional activities of the amine neurotransmitters, and without inducing a "cheese reaction". This was not possible until recently, with the development of the novel cholinesterase-brain selective MAO-AB inhibitor, TV3326 (N-propargyl-(3R)-aminoidnan-5-yl-ethyl methylcarbamate hemitartiate), a carbamate derivative of the irreversible MAO-B inhibitor anti-Parkinson drug, rasagiline. This drug is a brain selective MAO-A and B inhibitor, with little inhibition of liver and small intestine enzymes. Pharmacologically it has limited tyramine potentiation, very similar to moclobemide and being a MAO-AB inhibitor it

  1. Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase ll)

    Energy Technology Data Exchange (ETDEWEB)

    Collard, F.; Zhang, J; Nemet, I; Qanungo, K; Monnier, V; Yee, V

    2008-01-01

    Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6{angstrom} resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12{angstrom} deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates.

  2. Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)

    Energy Technology Data Exchange (ETDEWEB)

    Collard, François; Zhang, Jianye; Nemet, Ina; Qanungo, Kaustubha R.; Monnier, Vincent M.; Yee, Vivien C. (Case Western)

    2009-01-12

    Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6{angstrom} resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12{angstrom} deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates.

  3. Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)*

    Science.gov (United States)

    Collard, François; Zhang, Jianye; Nemet, Ina; Qanungo, Kaustubha R.; Monnier, Vincent M.; Yee, Vivien C.

    2008-01-01

    Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6Å resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12Å deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates. PMID:18667417

  4. Crystal structure of the deglycating enzyme fructosamine oxidase (amadoriase II).

    Science.gov (United States)

    Collard, François; Zhang, Jianye; Nemet, Ina; Qanungo, Kaustubha R; Monnier, Vincent M; Yee, Vivien C

    2008-10-03

    Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6A resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12A deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates.

  5. Selective monoamine oxidase B inhibition by an Aphanizomenon flos-aquae extract and by its constitutive active principles phycocyanin and mycosporine-like amino acids.

    Science.gov (United States)

    Scoglio, Stefano; Benedetti, Yanina; Benvenuti, Francesca; Battistelli, Serafina; Canestrari, Franco; Benedetti, Serena

    2014-06-15

    Aphanizomenon flos-aquae (AFA) is a fresh water unicellular blue-green alga that has been traditionally used for over 25 years for its health-enhancing properties. Recent studies have shown the ability of a proprietary AFA extract (Klamin(®)) to improve mood, counteract anxiety, and enhance attention and learning. Aim of this study was to test the monoamine oxidase (MAO) inhibition activity of the same AFA extract and of its constituents phycocyanin (AFA-PC) and mycosporine-like aminoacids (AFA-MAAs). All compounds showed a dose-dependent selective inhibition of MAO-B activity as compared to MAO-A. The IC50 values of the AFA extract (concentration 10 mg/ml), AFA-PC and AFA-MAAs were 6.4 μl/ml, 1.33 μM and 1.98 μM, respectively, evidencing a mixed-type of inhibition for the AFA extract (Ki 0.99 μl/ml), a non-competitive inhibition for AFA-PC (Ki 1.06 μM) and a competitive inhibition for AFA-MAAs (Ki 0.585 μM). These results are important to explain the neuromodulating properties of the AFA extract Klamin(®), which is rich in phenylethylamine, a general neuromodulator, that would nevertheless rapidly destroyed by MAO-B enzymes without the inhibitory activity of the synergic active principles AFA-PC and AFA-MAAs. The present investigation thus proposes the extract as potentially relevant in clinical areas such as mood disorders and neurodegenerative diseases. Copyright © 2014 Elsevier GmbH. All rights reserved.

  6. Development of radioiodinated ligands for exploration of brain monoamine oxidase by tomo-scintigraphy; Developpement de ligands radioactifs pour l'exploration des monoamines oxydases cerebrales en tomoscintigraphie

    Energy Technology Data Exchange (ETDEWEB)

    Rafii, H

    1996-07-01

    Monoamine oxidases, MAO, are important in the regulation of monoaminergic neuro-transmissions. The fluctuations in MAO activities has been observed in some psychiatric and neuro-degenerative diseases. Thus, quantification of cerebral MAO activity would be useful for diagnosis and the therapeutic follow-up of these disorders. With the object of doing an in vivo scintigraphic exploration of cerebral MAO by SPECT, we have undertaken to synthesize some radioiodinated MAO inhibitors. In the first part of this work, we have discussed the general properties of the monoamine oxidases and their inhibitors. In the second part we have described the scintigraphic methods. the ligands to be used for MAO exploration, and the radioiodination methods. At last in the third part, the development of three radioiodinated ligands has been presented: - [{sup 125}I]3-iodopargyline. In vivo results showed that, this radioligand blocked the cerebral MAO-B with moderate selectivity. However, complementary in vivo studies would be needed to define precisely its activity.- [{sup 125}I]Ro 16-6491. The cerebral fixation of this radioligand was in accordance with the MAO-B sites in the rat brains, but its fixation was too low for scintigraphic exploration in vivo with iodine-123. - [{sup 125}I]Ro 11-9900. In vivo studies of rat brains showed that the MAO-A sites were bound preferentially by this radioligand. The cerebral biodistribution of this ligand labelled with iodine-123 is considered for use in a model animal nearest to human pathology. (author)

  7. The new inhibitor of monoamine oxidase, M30, has a neuroprotective effect against dexamethasone-induced brain cell apoptosis

    Directory of Open Access Journals (Sweden)

    Shakevia Johnson

    2010-11-01

    Full Text Available Stress detrimentally affects the brain and body and can lead to or be accompanied by depression. Although stress and depression may contribute to each other, the exact molecular mechanism underlying the effects is unclear. However, there is a correlation between stress and an increase in glucocorticoid secretion which causes a subsequent increase in monoamine oxidase (MAO activity during stress. Consequently, MAO inhibitors have been used as traditional antidepressant drugs. Cellular treatment with the synthetic glucocorticoid, dexamethasone (a cellular stressor, has been reported to markedly increase both MAO A and MAO B catalytic activities, as well as apoptosis. This study compares the neuroprotective abilities of M30 (a new generation inhibitor of both MAO A and MAO B with rasagiline (Azilect®, another new MAO B inhibitor and selegiline (Deprenyl®, a traditional MAO B inhibitor in the prevention of dexamethasone-induced brain cell death and MAO activity in human neuroblastoma cells, SH-SY5Y. M30 demonstrated the highest inhibitory effect on MAO A; however, M30 showed the lowest inhibitory effect on MAO B enzymatic activity in comparison to rasagiline and selegiline. Although, M30 exhibited the greatest neuroprotective effect by decreasing cell death rates and apoptotic DNA damage compared to rasagiline and selegiline, these neuroprotective effects of M30 were, overall, similar to rasagiline. Summarily, M30 has a generally greater impact on neuroprotection than the MAO B inhibitors, selegiline and rasagiline. Our results suggest that M30 may have great potential in alleviating disorders involving increases in both MAO A and MAO B, such as stress-induced disorders.

  8. Controversies in Neurology: why monoamine oxidase B inhibitors could be a good choice for the initial treatment of Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Reichmann Heinz

    2011-09-01

    Full Text Available Abstract Background Early initiation of pharmacotherapy in Parkinson's disease (PD is nowadays widely advocated by experts since the delay of treatment has shown to be associated with a significant deterioration of health related quality of life in affected patients. Due to marked advances in PD treatment during the last decades, physicians are nowadays fortunately equipped with a variety of substances that can effectively ameliorate emerging motor symptoms of the disease, among them levodopa, dopamine agonists and monoamine oxidase type B (MAO-B inhibitors. Despite numerous drug intervention trials in early PD, there is however still ongoing controversy among neurologists which substance to use for the initial treatment of the disease. Discussion In multiple studies, MAO-B inhibitors, such as selegiline and rasagiline, have shown to provide mild symptomatic effects, delay the need for levodopa, and to reduce the incidence of motor fluctuations. Although their symptomatic efficacy is inferior compared to dopamine agonists and levodopa, MAO-B inhibitors undoubtedly have fewer side effects and are easy to administer. In contrary to their competitors, MAO-B inhibitors may furthermore offer a chance for disease modification, which so far remains a major unmet need in the management of PD and eventually makes them ideal candidates for the early treatment of the disease. Summary MAO-B inhibitors may constitute a preferable therapeutic option for early PD, mainly due to their favourable safety profile and their putative neuroprotective capabilities. Since the symptomatic effects of MAO-B inhibitors are comparatively mild, dopamine agonists and levodopa should however be considered for initial treatment in those PD patients, in whom robust and immediate symptomatic relief needs to be prioritized.

  9. In vitro, in vivo, and clinical studies of tedizolid to assess the potential for peripheral or central monoamine oxidase interactions.

    Science.gov (United States)

    Flanagan, S; Bartizal, K; Minassian, S L; Fang, E; Prokocimer, P

    2013-07-01

    Tedizolid phosphate is a novel oxazolidinone prodrug whose active moiety, tedizolid, has improved potency against Gram-positive pathogens and pharmacokinetics, allowing once-daily administration. Given linezolid warnings for drug-drug and drug-food interactions mediated by monoamine oxidase (MAO) inhibition, including sporadic serotonergic toxicity, these studies evaluated tedizolid for potential MAO interactions. In vitro, tedizolid and linezolid were reversible inhibitors of human MAO-A and MAO-B; the 50% inhibitory concentration (IC50) for tedizolid was 8.7 μM for MAO-A and 5.7 μM for MAO-B and 46.0 and 2.1 μM, respectively, with linezolid. Tedizolid phosphate was negative in the mouse head twitch model of serotonergic activity. Two randomized placebo-controlled crossover clinical studies assessed the potential of 200 mg/day tedizolid phosphate (at steady state) to enhance pressor responses to coadministered oral tyramine or pseudoephedrine. Sensitivity to tyramine was determined by comparing the concentration of tyramine required to elicit a ≥ 30-mmHg increase in systolic blood pressure (TYR30) when administered with placebo versus tedizolid phosphate. The geometric mean tyramine sensitivity ratio (placebo TYR30/tedizolid phosphate TYR30) was 1.33; a ratio of ≥ 2 is considered clinically relevant. In the pseudoephedrine study, mean maximum systolic blood pressure was not significantly different when pseudoephedrine was coadministered with tedizolid phosphate versus placebo. In summary, tedizolid is a weak, reversible inhibitor of MAO-A and MAO-B in vitro. Provocative testing in humans and animal models failed to uncover significant signals that would suggest potential for hypertensive or serotonergic adverse consequences at the therapeutic dose of tedizolid phosphate. Clinical studies are registered at www.clinicaltrials.gov as NCT01539473 (tyramine interaction study conducted at Covance Clinical Research Center, Evansville, IN) and NCT01577459

  10. Xanthoangelol and 4-Hydroxyderricin Are the Major Active Principles of the Inhibitory Activities against Monoamine Oxidases on Angelica keiskei K.

    Science.gov (United States)

    Kim, Ji Ho; Son, Yeon Kyung; Kim, Gun Hee; Hwang, Keum Hee

    2013-05-30

    Monoamine oxidase inhibitors (MAOI) have been widely used as antidepressants. Recently, there has been renewed interest in MAO inhibitors. The activity-guided fractionation of extracts from Angelica keiskei Koidzumi (A. keiskei K.) led to the isolation of two prenylated chalcones, xanthoangelol and 4-hydroxyderricin and a flavonoid, cynaroside. These three isolated compounds are the major active ingredients of A. keiskei K. to inhibit the MAOs and DBH activities. Xanthoangelol is a nonselective MAO inhibitor, and a potent dopamine β-hydroxylase (DBH) inhibitor. IC50 values of xanthoangelol to MAO-A and MAO-B were calculated to be 43.4 μM, and 43.9 μM. These values were very similar to iproniazid, which is a nonselective MAO inhibitor used as a drug against depression. The IC50 values of iproniazid were 37 μM, and 42.5 μM in our parallel examination. Moreover, IC50 value of xanthoangelol to DBH was calculated 0.52 μM. 4-Hydroxyderricin is a potent selective MAO-B inhibitor and also mildly inhibits DBH activity. The IC50 value of 4-hydroxyderricin to MAO-B was calculated to be 3.43 μM and this value was higher than that of deprenyl (0.046 μM) used as a positive control for selective MAO-B inhibitor in our test. Cynaroside is a most potent DBH inhibitor. The IC50 value of cynaroside to DBH was calculated at 0.0410 μM. Results of this study suggest that the two prenylated chalcones, xanthoangelol and 4-hydroxyderricin isolated from A. keiskei K., are expected for potent candidates for development of combined antidepressant drug. A. keiskei K. will be an excellent new bio-functional food material that has the combined antidepressant effect.

  11. Azure B, a metabolite of methylene blue, is a high-potency, reversible inhibitor of monoamine oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Petzer, Anél, E-mail: 12264954@nwu.ac.za [Unit for Drug Research and Development, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520 (South Africa); Harvey, Brian H. [Division of Pharmacology, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520 (South Africa); Wegener, Gregers [Centre for Psychiatric Research, Aarhus University Hospital-Risskov, Skovagervej 2, 8240 Risskov (Denmark); Petzer, Jacobus P. [Division of Pharmaceutical Chemistry, School of Pharmacy, North-West University, Private Bag X6001, Potchefstroom, 2520 (South Africa)

    2012-02-01

    Methylene blue (MB) has been shown to act at multiple cellular and molecular targets and as a result possesses diverse medical applications. Among these is a high potency reversible inhibition of monoamine oxidase A (MAO-A) that may, at least in part, underlie its adverse effects but also its psycho- and neuromodulatory actions. MB is metabolized to yield N-demethylated products of which azure B, the monodemethyl species, is the major metabolite. Similar to MB, azure B also displays a variety of biological activities and may therefore contribute to the pharmacological profile of MB. Based on these observations, the present study examines the interactions of azure B with recombinant human MAO-A and -B. The results show that azure B is a potent MAO-A inhibitor (IC{sub 50} = 11 nM), approximately 6-fold more potent than is MB (IC{sub 50} = 70 nM) under identical conditions. Measurements of the time-dependency of inhibition suggest that the interaction of azure B with MAO-A is reversible. Azure B also reversibly inhibits the MAO-B isozyme with an IC{sub 50} value of 968 nM. These results suggest that azure B may be a hitherto under recognized contributor to the pharmacology and toxicology of MB by blocking central and peripheral MAO-A activity and as such needs to be considered during its use in humans and animals. Highlights: ► Methylene blue (MB) is a known potent MAO-A inhibitor. ► Azure B, the major metabolite of MB, is more potent as a MAO-A inhibitor. ► Azure B may be a contributor to the CNS pharmacology and toxicology of MB.

  12. Inhibitory effect of chlorpromazine on the syndrome of hyperactivity produced by L-tryptophan or 5-methoxy-N,N-dimethyltryptamine in rats treated with a monoamine oxidase inhibitor

    Science.gov (United States)

    Grahame-Smith, D. G.

    1971-01-01

    1. The hyperactivity and hyperpyrexia produced by L-tryptophan in rats treated with a monoamine oxidase inhibitor was inhibited by chlorpromazine. 2. Chlorpromazine did not inhibit the increased rate of synthesis of brain 5-hydroxytryptamine (5-HT) produced by tryptophan loading. 3. Hyperactivity and hyperpyrexia were also produced by 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) in rats. Pretreatment with a monoamine oxidase inhibitor potentiated the hyperactivity response. Pretreatment of rats with p-chlorophenylalanine did not inhibit hyperactivity produced by 5-MeODMT. 4. Chlorpromazine inhibits hyperactivity caused by tryptophan or 5-MeODMT after monoamine oxidase inhibition either by competition with 5-HT or 5-MeODMT, respectively, at receptor sites or by physiological antagonism. PMID:4261561

  13. Monoamine oxidases and alcoholism. I. Studies in unrelated alcoholics and normal controls

    Energy Technology Data Exchange (ETDEWEB)

    Parsian, A.; Suarez, B.K.; Fisher, L. [Washington Univ. School of Medicine, St. Louis, MO (United States)] [and others

    1995-10-09

    Low platelet MAO activity has been associated with alcoholism. In order to evaluate the role of MAO genes in susceptibility to alcoholism, we have taken a biochemical and molecular genetic approach. The sample consisted of 133 alcoholic probands who were classified by subtypes of alcoholism and 92 normal controls. For those subjects typed for platelet MAO activity, alcoholics (N = 74) were found not to differ from the non-alcoholic controls (N = 34). Neither was there a significant difference between type I and type II alcoholics or between either subtype and normal controls. However, we do find significant differences between male and female alcoholics, but not between male and female controls. The allele frequency distribution for the MAO-A and MAO-B dinucleotide repeats is different between the alcoholic sample (N = 133) and the normal control sample (N = 92). In a two-way analysis of variance of MAO-B activity as a function of the allelic variation of each marker locus and diagnosis, there is no evidence for mean differences in activity levels for the different alleles. Our findings do not rule out a role for the MAO-B gene in controlling the enzyme activity because the dinucleotide repeats are located in introns. 52 refs., 1 figs., 4 tabs.

  14. Modification of the effects of 5-methoxy-N,N-dimethyltryptamine on exploratory behavior in rats by monoamine oxidase inhibitors.

    Science.gov (United States)

    Halberstadt, Adam L; Buell, Mahalah R; Masten, Virginia L; Risbrough, Victoria B; Geyer, Mark A

    2008-11-01

    The hallucinogenic tea known as ayahuasca is made from a combination of psychoactive plants that contribute the active components N,N-dimethyltryptamine (DMT) and 5-methoxy-DMT (5-MeO-DMT), as well as the monoamine oxidase (MAO) inhibitors (MAOIs) harmine and harmaline for oral activity. The present study examined the effects of 5-MeO-DMT in combination with MAOIs in rats using the behavioral pattern monitor, which enables analyses of patterns of locomotor activity and exploration. Interaction studies using the serotonin (5-HT)(1A) antagonist WAY-100635 (1.0 mg/kg) and the 5-HT(2A) antagonist MDL 11,939 (1.0 mg/kg) were also performed to assess the respective contributions of these receptors to the behavioral effects of 5-MeO-DMT in MAOI-treated animals. 5-MeO-DMT (0.01, 0.1, and 1.0 mg/kg) decreased locomotor activity and investigatory behavior. In rats pretreated with a behaviorally inactive dose of harmaline (0.1 mg/kg), 1.0 mg/kg 5-MeO-DMT had biphasic effects on locomotor activity, initially reducing locomotion and then increasing activity as time progressed. The ability of harmaline to shift 5-MeO-DMT to a biphasic locomotor pattern was shared by the selective MAO(A) inhibitor clorgyline, whereas the selective MAO(B) inhibitor (-)-deprenyl was ineffective. The late hyperactivity induced by the combination of 1.0 mg/kg 5-MeO-DMT and 0.3 mg/kg clorgyline was blocked by pretreatment with MDL 11,939. Pretreatment with WAY-100635 failed to attenuate either the early hypoactivity or the late hyperactivity. The ability of harmaline to modify the behavioral effects of 5-MeO-DMT is mediated by the inhibition of MAO(A). Furthermore, 5-HT(2A) receptors are responsible for the late hyperactivity induced by 5-MeO-DMT in the presence of MAO(A) inhibitors.

  15. Modification of the effects of 5-methoxy-N,N-dimethyltryptamine on exploratory behavior in rats by monoamine oxidase inhibitors

    Science.gov (United States)

    Halberstadt, Adam L.; Buell, Mahalah R.; Masten, Virginia L.; Risbrough, Victoria B.; Geyer, Mark A.

    2010-01-01

    RATIONALE The hallucinogenic tea known as ayahuasca is made from a combination of psychoactive plants that contribute the active components N,N-dimethyltryptamine (DMT) and 5-methoxy-DMT (5-MeO-DMT), as well as the monoamine oxidase (MAO) inhibitors (MAOIs) harmine and harmaline for oral activity. OBJECTIVE The present study examined the effects of 5-MeO-DMT in combination with MAOIs in rats using the Behavioral Pattern Monitor (BPM), which enables analyses of patterns of locomotor activity and exploration. Interaction studies using the serotonin (5-HT)1A antagonist WAY-100635 (1.0 mg/kg) and the 5-HT2A antagonist MDL 11,939 (1.0 mg/kg) were also performed to assess the respective contributions of these receptors to the behavioral effects of 5-MeO-DMT in MAOI-treated animals. RESULTS 5-MeO-DMT (0.01, 0.1, and 1.0 mg/kg) decreased locomotor activity and investigatory behavior. In rats pretreated with a behaviorally inactive dose of harmaline (0.1 mg/kg), 1.0 mg/kg 5-MeO-DMT had biphasic effects on locomotor activity, initially reducing locomotion and then increasing activity as time progressed. The ability of harmaline to shift 5-MeO-DMT to a biphasic locomotor pattern was shared by the selective MAOA inhibitor clorgyline, whereas the selective MAOB inhibitor (−)-deprenyl was ineffective. The late hyperactivity induced by the combination of 1.0 mg/kg 5-MeO-DMT and 0.3 mg/kg clorgyline was blocked by pretreatment with MDL 11,939. Pretreatment with WAY-100635 failed to attenuate either the early hypoactivity or the late hyperactivity. CONCLUSIONS The ability of harmaline to modify the behavioral effects of 5-MeO-DMT is mediated by inhibition of MAOA. Further, 5-HT2A receptors are responsible for the late hyperactivity induced by 5-MeO-DMT in the presence of MAOA inhibitors. PMID:18604652

  16. Monoamine oxidase inhibitors l-deprenyl and clorgyline protect nonmalignant human cells from ionising radiation and chemotherapy toxicity.

    LENUS (Irish Health Repository)

    Seymour, C B

    2003-11-17

    l-Deprenyl (R-(-)-deprenyl, selegiline) is an inhibitor of monoamine oxidase-B (MAO-B) that is known to protect nerve cells from a variety of chemical and physical insults. As apoptosis is a common mechanism of radiation-induced cell death, the effect of l-deprenyl on the survival of cultured cells and tissue explants was studied following exposure to gamma radiation. The results obtained were compared with the effects of the less-selective MAO-B inhibitor pargyline and the MAO-A inhibitor clorgyline. l-Deprenyl at a concentration of 10(-9) M protected the nontumorigenic cell line (HaCaT) and normal human urothelial explants from the effects of cobalt-60 gamma radiation, but did not protect tumorigenic human cell lines HaCaT-ras, HPV-transfected human keratinocytes (HPV-G cells), or PC3. Human bladder carcinoma explants were not protected. Clorgyline showed a smaller protective effect of normal cells, whereas pargyline had no effect. Radiation-induced delayed effects (genomic instability measured as delayed cell death) were prevented in normal cells by l-deprenyl but, interestingly, deprenyl appeared to increase the amount of delayed death in the tumorigenic cell lines. Studies using l-deprenyl prior to the exposure of nonmalignant cells to cisplatin showed that cell death due to this agent was also reduced. Treatment of cultures of nontumorigenic cells with l-deprenyl or clorgyline significantly increased the levels of the protein Bcl-2 following irradiation, but there was no such effect on the already-elevated levels of this protein in the tumour samples. Since the Bcl-2 has been shown to be an inhibitor of apoptosis or programmed cell death, this would imply that the protective effects of l-deprenyl and clorgyline involve activation of antiapoptotic pathways within the normal cell. This hypothesis is supported by data showing reduced levels of apoptosis in HaCAT cells and in normal bladder explant cultures following treatment with l-deprenyl.

  17. Effects of monoamine oxidase inhibitor and cytochrome P450 2D6 status on 5-methoxy-N,N-dimethyltryptamine metabolism and pharmacokinetics.

    Science.gov (United States)

    Shen, Hong-Wu; Wu, Chao; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-07-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural psychoactive indolealkylamine drug that has been used for recreational purpose. Our previous study revealed that polymorphic cytochrome P450 2D6 (CYP2D6) catalyzed 5-MeO-DMT O-demethylation to produce active metabolite bufotenine, while 5-MeO-DMT is mainly inactivated through deamination pathway mediated by monoamine oxidase (MAO). This study, therefore, aimed to investigate the impact of CYP2D6 genotype/phenotype status and MAO inhibitor (MAOI) on 5-MeO-DMT metabolism and pharmacokinetics. Enzyme kinetic studies using recombinant CYP2D6 allelic isozymes showed that CYP2D6.2 and CYP2D6.10 exhibited 2.6- and 40-fold lower catalytic efficiency (V(max)/K(m)), respectively, in producing bufotenine from 5-MeO-DMT, compared with wild-type CYP2D6.1. When co-incubated with MAOI pargyline, 5-MeO-DMT O-demethylation in 10 human liver microsomes showed significantly strong correlation with bufuralol 1'-hydroxylase activities (R(2)=0.98; P<0.0001) and CYP2D6 contents (R(2)=0.77; P=0.0007), whereas no appreciable correlations with enzymatic activities of other P450 enzymes. Furthermore, concurrent MAOI harmaline sharply reduced 5-MeO-DMT depletion and increased bufotenine formation in human CYP2D6 extensive metabolizer hepatocytes. In vivo studies in wild-type and CYP2D6-humanized (Tg-CYP2D6) mouse models showed that Tg-CYP2D6 mice receiving the same dose of 5-MeO-DMT (20mg/kg, i.p.) had 60% higher systemic exposure to metabolite bufotenine. In addition, pretreatment of harmaline (5mg/kg, i.p.) led to 3.6- and 4.4-fold higher systemic exposure to 5-MeO-DMT (2mg/kg, i.p.), and 9.9- and 6.1-fold higher systemic exposure to bufotenine in Tg-CYP2D6 and wild-type mice, respectively. These findings indicate that MAOI largely affects 5-MeO-DMT metabolism and pharmacokinetics, as well as bufotenine formation that is mediated by CYP2D6. (c) 2010 Elsevier Inc. All rights reserved.

  18. Multiple amine oxidases in cucumber seedlings.

    Science.gov (United States)

    Percival, F W; Purves, W K

    1974-10-01

    Cell-free extracts of cucumber (Cucumis sativus L. cv. National Pickling) seedlings were found to have amine oxidase activity when assayed with tryptamine as a substrate. Studies of the effect of lowered pH on the extract indicated that this activity was heterogeneous, and three amine oxidases could be separated by ion exchange chromatography. The partially purified enzymes were tested for their activities with several substrates and for their sensitivities to various amine oxidase inhibitors. One of the enzymes may be a monoamine oxidase, although it is inhibited by some diamine oxidase inhibitors. The other two enzymes have properties more characteristic of the diamine oxidases. The possible relationship of the amine oxidases to indoleacetic acid biosynthesis in cucumber seedlings is discussed.

  19. Polystyrene Attached Pt(IV)–Azomethine, Synthesis and Immobilization of Glucose Oxidase Enzyme

    Science.gov (United States)

    Sarı, Nurşen; Antepli, Esin; Nartop, Dilek; Yetim, Nurdan Kurnaz

    2012-01-01

    Modified polystyrene with Pt(IV)–azomethine (APS–Sch–Pt) was synthesized by means of condensation and demonstrated to be a promising enzyme support by studying the enzymatic properties of glucose oxidase enzyme (GOx) immobilized on it. The characteristics of the immobilized glucose oxidase (APS–Sch–Pt–GOx) enzyme showed two optimum pH values that were pH = 4.0 and pH = 7. The insertion of stable Pt(IV)–azomethine spacers between the polystyrene backbone and the immobilized GOx, (APS–Sch–Pt–GOx), increases the enzymes’ activity and improves their affinity towards the substrate even at pH = 4. The influence of temperature, reusability and storage capacity on the free and immobilized glucose oxidase enzyme was investigated. The storage stability of the immobilized glucose oxidase was shown to be eleven months in dry conditions at +4 °C. PMID:23109888

  20. Immobilization of the enzyme polyphenol oxidase on dendrispheres: In partial fulfilment of the degree Magister Scientiae

    CSIR Research Space (South Africa)

    Bannister, M

    2011-04-01

    Full Text Available and loquat homogenates: ?Much larger theaflavin synthesis capacity than fresh tea leaves ?Highest among 62 plants belonging to 49 families ?Type-3 copper enzyme with a dinuclear copper centre ?Mixed function oxidase: ?Monophenolase activity (ortho...

  1. Oxidative phenols in forage crops containing polyphenol oxidase enzymes.

    Science.gov (United States)

    Parveen, Ifat; Threadgill, Michael D; Moorby, Jon M; Winters, Ana

    2010-02-10

    Polyphenol oxidases (PPOs) are copper-containing enzymes that catalyze oxidation of endogenous monophenols to ortho-dihydroxyaryl compounds and of ortho-dihydroxyaryl compounds to ortho-quinones. Subsequent nucleophilic addition reactions of phenols, amino acids, and proteins with the electrophilic ortho-quinones form brown-, black-, or red-colored secondary products associated with the undesired discolouration of fruit and vegetables. Several important forage plants also exhibit significant PPO activity, and a link with improved efficiency of ruminant production has been established. In ruminant animals, extensive degradation of forage proteins, following consumption, can result in high rates of excretion of nitrogen, which contributes to point-source and diffuse pollution. Reaction of quinones with forage proteins leads to the formation of protein-phenol complexes that are resistant to proteolytic activity during ensilage and during rumen fermentation. Thus, PPO in red clover (Trifolium pratense) has been shown to improve protein utilization by ruminants. While PPO activity has been demonstrated in a number of forage crops, little work has been carried out to identify substrates of PPO, knowledge of which would be beneficial for characterizing this trait in these forages. In general, a wide range of 1,2-dihydroxyarenes can serve as PPO substrates because these are readily oxidized because of the ortho positioning of the hydroxy groups. Naturally occurring phenols isolated from forage crops with PPO activity are reviewed. A large number of phenols, which may be directly or indirectly oxidized as a consequence of PPO activity, have been identified in several forage grass, legume, cereal, and brassica species; these include hydroxybenzoic acids, hydroxycinnamates, and flavonoids. In conclusion, a number of compounds are known or postulated to enable PPO activity in important PPO-expressing forage crops. Targeting the matching of these compounds with PPO activity

  2. Piceatannol and resveratrol share inhibitory effects on hydrogen peroxide release, monoamine oxidase and lipogenic activities in adipose tissue, but differ in their antilipolytic properties.

    Science.gov (United States)

    Les, Francisco; Deleruyelle, Simon; Cassagnes, Laure-Estelle; Boutin, Jean A; Balogh, Balázs; Arbones-Mainar, José M; Biron, Simon; Marceau, Picard; Richard, Denis; Nepveu, Françoise; Mauriège, Pascale; Carpéné, Christian

    2016-10-25

    Piceatannol is a hydroxylated derivative of resveratrol. While both dietary polyphenols coexist in edible plants and fruits, and share equivalent concentrations in several wines, the influence of piceatannol on adiposity has been less studied than that of resveratrol. Though resveratrol is now recognized to limit fat deposition in various obesity models, the benefit of its dietary supplementation remains under debate regarding human obesity treatment or prevention. The research for more potent resveratrol analogs is therefore still undergoing. This prompted us to compare various effects of piceatannol and resveratrol directly on human adipose tissue (hAT). Hydrogen peroxide release was measured by Amplex Red-based fluorescence in subcutaneous hAT samples from obese patients. Interactions of stilbenes with human amine oxidases and quinone reductase were assessed by radiometric methods, computational docking and electron paramagnetic resonance. Influences on lipogenic and lipolytic activities were compared in mouse adipocytes. Resveratrol and piceatannol inhibited monoamine oxidase (MAO) with respective IC50 of 18.5 and 133.7 μM, but not semicarbazide-sensitive amine oxidase (SSAO) in hAT. For both stilbenes, the docking scores were better for MAO than for SSAO. Piceatannol and resveratrol similarly hampered hydrogen peroxide detection in assays with and without hAT, while they shared pro-oxidant activities when incubated with purified quinone reductase. They exhibited similar dose-dependent inhibition of adipocyte lipogenic activity. Only piceatannol inhibited basal and stimulated lipolysis when incubated at a dose ≥100 μM. Thus, piceatannol exerted on fat cells dose-dependent effects similar to those of resveratrol, except for a stronger antilipolytic action. In this regard, piceatannol should be useful in limiting the lipotoxicity related to obesity when ingested or administered alone - or might hamper the fat mobilization induced by resveratrol when

  3. Multilayered polyelectrolyte microcapsules: interaction with the enzyme cytochrome C oxidase.

    Science.gov (United States)

    Pastorino, Laura; Dellacasa, Elena; Noor, Mohamed R; Soulimane, Tewfik; Bianchini, Paolo; D'Autilia, Francesca; Antipov, Alexei; Diaspro, Alberto; Tofail, Syed A M; Ruggiero, Carmelina

    2014-01-01

    Cell-sized polyelectrolyte capsules functionalized with a redox-driven proton pump protein were assembled for the first time. The interaction of polyelectrolyte microcapsules, fabricated by electrostatic layer-by-layer assembly, with cytochrome c oxidase molecules was investigated. We found that the cytochrome c oxidase retained its functionality, that the functionalized microcapsules interacting with cytochrome c oxidase were permeable and that the permeability characteristics of the microcapsule shell depend on the shell components. This work provides a significant input towards the fabrication of an integrated device made of biological components and based on specific biomolecular functions and properties.

  4. Multilayered polyelectrolyte microcapsules: interaction with the enzyme cytochrome C oxidase.

    Directory of Open Access Journals (Sweden)

    Laura Pastorino

    Full Text Available Cell-sized polyelectrolyte capsules functionalized with a redox-driven proton pump protein were assembled for the first time. The interaction of polyelectrolyte microcapsules, fabricated by electrostatic layer-by-layer assembly, with cytochrome c oxidase molecules was investigated. We found that the cytochrome c oxidase retained its functionality, that the functionalized microcapsules interacting with cytochrome c oxidase were permeable and that the permeability characteristics of the microcapsule shell depend on the shell components. This work provides a significant input towards the fabrication of an integrated device made of biological components and based on specific biomolecular functions and properties.

  5. [{sup 11}C]S.L.(25.1188), a new radioligand to study the monoamine oxidase type B with PET: preclinical characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Saba, W.; Valette, H.; Peyronneau, M.A.; Bramoulle, Y.; Coulon, C.; Dolle, F.; Bottlaender, M. [Service Hospitalier Frederic Joliot, IIBM/DSV, 91 - Orsay (France); Curet, O.; George, P. [Sanofi-Aventis, 92 - Bagneux (France)

    2008-02-15

    Introduction. - Monoamine oxidase (M.A.O.) is a flavin containing enzyme, that catalyzes the oxidative deamination of various amines and neurotransmitters. Two isoforms exist, M.A.O.-A and M.A.O.-B. Variations in M.A.O. activity may be associated to human disease such as Parkinson and Alzheimer disease. Few radiotracers have been developed for M.A.O. PET studies such as [{sup 11}C]deprenyl, an irreversible M.A.O.-B inhibitor. Recently an oxazolidinone derivative, S.L.- 25.1188 ((S)-5-methoxy-methyl-3-[6-(4,4,4-tri-fluoro butoxy)- benzo[d]isoxazol-3-yl]-oxazolidin-2-one), belonging to a new generation of selective and reversible M.A.O.-B inhibitors was developed and showed in vitro a high selectivity for M.A.O.B. [1]. The aim of this study was to characterize [{sup 11}C]S.L.- 25.1188 as radioligand for in vivo PET examination of M.A.O.-B. Materials and methods. - PET studies of the brain distribution were carried out in male Papio anubis baboons. Selectivity and reversibility of [{sup 11}C]S.L.-25.1188 binding for M.A.O.-B was assessed by pre-treatment or displacement experiments (30 min before and after tracer injection, respectively) using reference ligands for M.A.O.-B (deprenyl: 2 mg/kg i.v. and lazabemide: 0.5 mg/kg i.v.) or by displacement experiments using unlabelled S.L.-25.1188 (1 mg/kg, i.v., 30 min after tracer injection). Distribution volume (D.V.) was calculated using 2-tissue-compartment model. The saturable binding following pre-treatment with deprenyl was considered as the specific binding. Results. - After injection, [1{sup 1C}]S.L.-25.1188 presents a rapid phase of distribution in blood (about 5 min), followed by a elimination with T1/2 of 75 min. The Blood to plasma concentration ratio was constant during the experimentation (0.9 {+-} .04) consistent with a similar kinetic of [{sup 11}C]S.L.- 25.1188 in both blood and plasma. Metabolism analysis showed that [{sup 11}C]S.L.-25.1188 is stable in vivo. In the brain, uptake in different areas was

  6. Discovery of highly selective and potent monoamine oxidase B inhibitors: Contribution of additional phenyl rings introduced into 2-aryl-1,3,4-oxadiazin-5(6H)-one.

    Science.gov (United States)

    Lee, Jungeun; Lee, Yeongcheol; Park, So Jung; Lee, Joohee; Kim, Yeong Shik; Suh, Young-Ger; Lee, Jeeyeon

    2017-03-01

    Monoamine oxidase B (MAO-B) is a flavin adenine dinucleotide (FAD)-containing enzyme that plays a major role in the oxidative deamination of biogenic amines and neurotransmitters. Inhibiting MAO-B activity is a promising approach in the treatment of neurological disorders. Here, we report a series of 2-aryl-1,3,4-oxadiazin-5(6H)-one derivatives as highly selective and potent MAO-B inhibitors. Analysis of the binding sites of hMAO-A and hMAO-B led to design of linear analogs of 2-aryl-1,3,4-oxadiazin-5(6H)-one with an additional phenyl ring. Biological evaluation of the 26 new derivatives resulted in the identification of highly potent and selective inhibitors with optimal physicochemical properties to potentially cross the blood-brain barrier (BBB). Compounds 18a, 18b, 18e and 25b potently inhibited MAO-B, with IC50 values of 4-25 nM and excellent SI over MAO-A (18a > 25000, 18b > 8333 and 18e > 4000 and 25b > 4545). Docking results suggest that an optimal linker between two aromatic rings on the 2-aryl-1,3,4-oxadiazin-5(6H)-one scaffold is a key element in the binding and inhibition of MAO-B.

  7. No changes in lymphocyte muscarinic receptors and platelet monoamine oxidase-B examined as surrogate central nervous system biomarkers in a Faroese children cohort prenatally exposed to methylmercury and polychlorinated biphenyls

    DEFF Research Database (Denmark)

    Coccini, Teresa; Manzo, Luigi; Debes, Frodi

    2009-01-01

    Experimental evidence suggests that monoamine oxidase B (MAO-B) and muscarinic cholinergic receptors (mAChRs) are involved in the pathogenesis of neurotoxicity caused by methylmercury and polychlorinated biphenyls (PCBs). Blood samples from 7-year-old exposed children were analyzed for platelet M....../or PCB exposure, whereas these markers are significantly altered in sustained exposure scenarios, as shown by clinical studies in drug addicts or patients treated with psychopharmacological agents....

  8. Spinach thylakoid polyphenol oxidase isolation, activation, and properties of the native chloroplast enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Golbeck, J.H.; Cammarata, K.V.

    1981-05-01

    Polyphenol oxidase activity (E.C. 1.14,18.1) has been found in two enzyme species isolated from thylakoid membranes of spinach chloroplasts. The proteins were released from the membrane by sonication and purified >900-fold by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography. The enzymes appear to be the tetramer and monomer of a subunit with a molecular weight of 42,500 as determined by lithium dodecyl sulfate gel electrophoresis. Sonication releases polyphenol oxidase from the membrane largely in the latent state. In the absence of added fatty acids, the isolated enzyme spontaneously, but slowly, activates with time. Purified polyphenol oxidase utilizes o-diphenols as substrates and shows no detectable levels of monophenol or p-diphenol oxidase activities. Suitable substrates include chlorogenic acid, catechol, caffeic acid, pyrogallol, and dopamine; however, the enzyme is substrate-inhibited by the last four at concentrations near their K/sub m/. A large seasonal variation in polyphenol oxidase activity may result from a decrease in enzyme content rather than inhibition of the enzyme present.

  9. Rcf1 mediates cytochrome oxidase assembly and respirasome formation, revealing heterogeneity of the enzyme complex.

    Science.gov (United States)

    Vukotic, Milena; Oeljeklaus, Silke; Wiese, Sebastian; Vögtle, F Nora; Meisinger, Chris; Meyer, Helmut E; Zieseniss, Anke; Katschinski, Doerthe M; Jans, Daniel C; Jakobs, Stefan; Warscheid, Bettina; Rehling, Peter; Deckers, Markus

    2012-03-01

    The terminal enzyme of the mitochondrial respiratory chain, cytochrome oxidase, transfers electrons to molecular oxygen, generating water. Within the inner mitochondrial membrane, cytochrome oxidase assembles into supercomplexes, together with other respiratory chain complexes, forming so-called respirasomes. Little is known about how these higher oligomeric structures are attained. Here we report on Rcf1 and Rcf2 as cytochrome oxidase subunits in S. cerevisiae. While Rcf2 is specific to yeast, Rcf1 is a conserved subunit with two human orthologs, RCF1a and RCF1b. Rcf1 is required for growth in hypoxia and complex assembly of subunits Cox13 and Rcf2, as well as for the oligomerization of a subclass of cytochrome oxidase complexes into respirasomes. Our analyses reveal that the cytochrome oxidase of mitochondria displays intrinsic heterogeneity with regard to its subunit composition and that distinct forms of respirasomes can be formed by complex variants.

  10. Monoamine oxidase B single-photon emission tomography with [{sup 123}I]Ro 43-0463: imaging in volunteers and patients with temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Buck, A. [Division of Nuclear Medicine, University Hospital Zurich (Switzerland); Frey, L.D. [Department of Nuclear Medicine, Kantonsspital Aarau (Switzerland); Blaeuenstein, P.; Schubiger, P. [Paul Scherrer Institut, Radiopharmacy Division, Villigen (Switzerland); Kraemer, G. [Swiss Epilepsy Clinic, Zurich (Switzerland); Siegel, A.; Weber, B.; Wieser, H.G. [Department of Neurology, University Hospital Zurich (Switzerland)

    1998-05-01

    Imaging of monoamine oxidase of subtype B (MAO B) is of interest in various neurological diseases. In the past non-invasive assessment of MAO B has only been possible with positron emission tomography (PET) ligands. Given the limited availability of PET, a single-photon emission tomography (SPET) ligand would be desirable. In this study SPET imaging with the new MAO B inhibitor [{sup 123}I]Ro 43-0463 was performed in five volunteers and nine patients with temporal lobe epilepsy (TLE). In two volunteers a second study was performed 12 h following blockade with deprenyl. In the TLE patients the tracer was administered as bolus (n = 4) or as prolonged infusion (n = 5). The regional uptake pattern correlated well with the known distribution of MAO B. In the two blocking studies ligand uptake was substantially reduced compared with baseline. In the TLE patients increased uptake was found in the ipsilateral mesial temporal lobe and, surprisingly, in the ipsilateral putamen. This study indicates the potential of the new SPET ligand [{sup 123}I]Ro 43-0463 to map MAO B concentration in the human brain. The new finding of increased MAO B in the putamen of TLE patients needs further studies to elucidate its exact pathophysiology. (orig.) With 3 figs., 3 tabs., 28 refs.

  11. Duration of hexobarbital-induced sleep and monoamine oxidase activities in rat brain: Focus on the behavioral activity and on the free-radical oxidation.

    Science.gov (United States)

    Tseilikman, Vadim E; Kozochkin, Denis A; Manukhina, Eugenia B; Downey, H Fred; Tseilikman, Olga B; Misharina, Maria E; Nikitina, Anna A; Komelkova, Maria V; Lapshin, Maxim S; Kondashevskaya, Marina V; Lazuko, Svetlana S; Kusina, Oxana V; Sahabutdinov, Marat V

    2016-04-01

    The present study is focused on the relationship between monoamine oxidase (MAO) activity and hepatic content of cytochrome P450 (CYP), which reflects the status of microsomal oxidation. For vital integrative evaluation of hepatic microsomal oxidation in rats, the hexobarbital sleep test was used, and content of CYP was measured in hepatic microsomes. Rats with short hexobarbital sleep time (SHST) had higher content of microsomal CYP than rats with long hexobarbital sleep time (LHST). Whole brain MAO-A and MAO-B activities, serotonin and carbonylated protein levels were higher in SHST than in LHST rats. MAO-A and MAO-B activities were higher in brain cortex of SHST rats; MAO-A activity was higher only in hypothalamus and medulla of LHST. The same brain regions of LHST rats had higher concentrations of carbonylated proteins and lipid peroxidation products than in SHST rats. MAO activity was correlated with microsomal oxidation phenotype. Rats with higher hepatic content of CYP had higher activities of MAO-A and MAO-B in the brain and higher plasma serotonin levels than rats with lower microsomal oxidation. In conclusion, data obtained in this study showed a correlation between MAO activity and microsomal oxidation phenotype.

  12. Elevated Monoamine Oxidase-A Distribution Volume in Borderline Personality Disorder Is Associated With Severity Across Mood Symptoms, Suicidality, and Cognition.

    Science.gov (United States)

    Kolla, Nathan J; Chiuccariello, Lina; Wilson, Alan A; Houle, Sylvain; Links, Paul; Bagby, R Michael; McMain, Shelley; Kellow, Charis; Patel, Jalpa; Rekkas, Paraskevi V; Pasricha, Suvercha; Meyer, Jeffrey H

    2016-01-15

    Monoamine oxidase-A (MAO-A) is a treatment target in neurodegenerative illness and mood disorders that increases oxidative stress and predisposition toward apoptosis. Increased MAO-A levels in prefrontal cortex (PFC) and anterior cingulate cortex (ACC) occur in rodent models of depressive behavior and human studies of depressed moods. Extreme dysphoria is common in borderline personality disorder (BPD), especially when severe, and the molecular underpinnings of severe BPD are largely unknown. We hypothesized that MAO-A levels in PFC and ACC would be highest in severe BPD and would correlate with symptom magnitude. [(11)C] Harmine positron emission tomography measured MAO-A total distribution volume (MAO-A VT), an index of MAO-A density, in severe BPD subjects (n = 14), moderate BPD subjects (n = 14), subjects with a major depressive episode (MDE) only (n = 14), and healthy control subjects (n = 14). All subjects were female. Severe BPD was associated with greater PFC and ACC MAO-A VT compared with moderate BPD, MDE, and healthy control subjects (multivariate analysis of variance group effect: F6,102 = 5.6, p multiple indicators of BPD severity, including BPD symptomatology, mood symptoms, suicidality, and neurocognitive impairment. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  13. Iron-chelating backbone coupled with monoamine oxidase inhibitory moiety as novel pluripotential therapeutic agents for Alzheimer's disease: a tribute to Moussa Youdim.

    Science.gov (United States)

    Weinreb, Orly; Mandel, Silvia; Bar-Am, Orit; Amit, Tamar

    2011-03-01

    It is for these authors a great privilege to dedicate this review article to Moussa Youdim, who is one of the most imperative pharmacologists and pioneer investigators in the search and development of novel therapeutics for neurodegenerative diseases. 40 years ago, Moussa Youdim has started studying brain iron, catecholamine receptor and monoamine oxidase (MAO)-A and -B functions. Although Moussa Youdim succeeded in exploring the novel anti-Parkinsonian, selective MAO-B inhibitor drug, rasagiline (Azilect, Teva Pharmaceutical Co.), he did not stop searching for superior therapeutic approaches for neurodegenerative disorders. To date, Moussa Youdim and his research group are designing and synthesizing pluripotential drug candidates possessing diverse pharmacological properties that can act on multiple targets and pathological features ascribed to Parkinson's disease, Alzheimer's disease (AD) and amyotrophic lateral sclerosis. One such example is the multimodal non-toxic, brain-permeable iron-chelating compound, M30 (5-[N-methyl-N-propargylaminomethyl]-8-hydroxyquinoline), which amalgamates the propargyl moiety of rasagiline with the backbone of the potent iron chelator, VK28. This review discusses the multiple effects of several leading compounds of this series, concerning their neuroprotective/neurorestorative molecular mechanisms in vivo and in vitro, with a special focus on the pathological features ascribed to AD, including antioxidant and iron chelating activities, regulation of amyloid precursor protein and amyloid β peptide expression processing, activation of pro-survival signaling pathways and regulation of cell cycle and neurite outgrowth.

  14. Antiparkinsonian effects of aqueous methanolic extract of Hyoscyamus niger seeds result from its monoamine oxidase inhibitory and hydroxyl radical scavenging potency.

    Science.gov (United States)

    Sengupta, T; Vinayagam, J; Nagashayana, N; Gowda, B; Jaisankar, P; Mohanakumar, K P

    2011-01-01

    Hyoscyamus species is one of the four plants used in Ayurveda for the treatment of Parkinson's disease (PD). Since Hyoscyamus niger was found to contain negligible levels of L-DOPA, we evaluated neuroprotective potential, if any, of characterized petroleum ether and aqueous methanol extracts of its seeds in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD in mice. Air dried authenticated H. niger seeds were sequentially extracted using petroleum ether and aqueous methanol and were characterized employing HPLC-electrochemistry and LCMS. Parkinsonian mice were treated daily twice with the extracts (125-500 mg/kg, p.o.) for two days and motor functions and striatal dopamine levels were assayed. Administration of the aqueous methanol extract (containing 0.03% w/w of L-DOPA), but not petroleum ether extract, significantly attenuated motor disabilities (akinesia, catalepsy and reduced swim score) and striatal dopamine loss in MPTP treated mice. Since the extract caused significant inhibition of monoamine oxidase activity and attenuated 1-methyl-4-phenyl pyridinium (MPP+)-induced hydroxyl radical (·OH) generation in isolated mitochondria, it is possible that the methanolic extract of Hyoscyamus niger seeds protects against parkinsonism in mice by means of its ability to inhibit increased ·OH generated in the mitochondria.

  15. Inhibition of monoamine oxidase by derivatives of piperine, an alkaloid from the pepper plant Piper nigrum, for possible use in Parkinson's disease.

    Science.gov (United States)

    Al-Baghdadi, Osamah B; Prater, Natalie I; Van der Schyf, Cornelis J; Geldenhuys, Werner J

    2012-12-01

    A series of compounds related to piperine and antiepilepsirine was screened in a monoamine oxidase A and B assay. Piperine is an alkaloid from the source plant of both black and white pepper grains, Piper nigrum. Piperine has been shown to have a wide range of activity, including MAO inhibitory activity. The z-factor for the screening assay was found to be greater than 0.8 for both assays. Notably, the compounds tested were selective towards MAO-B, with the most potent compound having an IC(50) of 498 nM. To estimate blood-brain barrier (BBB) permeability, we used a PAMPA assay, which suggested that the compounds are likely to penetrate the BBB. A fluorescent bovine serum albumin (BSA) high-throughput screening (HTS) binding assay showed an affinity of 8 μM for piperine, with more modest binding for other test compounds. Taken together, the data described here may be useful in gaining insight towards the design of selective MAO-B inhibitory compounds devoid of MAO-A activity.

  16. PURIFICATION OF YEAST CYTOCHROME-C-OXIDASE WITH A SUBUNIT COMPOSITION RESEMBLING THE MAMMALIAN ENZYME

    OpenAIRE

    Taanman, J.W.; Capaldi, R A

    1992-01-01

    Yeast cytochrome c oxidase has been isolated by ion exchange chromatography using lauryl maltoside (n-dodecyl beta-D-maltoside) as the solubilizing detergent. The enzyme prepared in this way has a heme aa3 concentration of 8-9 nmol/mg of protein and a turnover number in the range of 180-210 s-1 at pH 6.2 in 0.01% lauryl maltoside at 20-degrees-C. Yeast cytochrome c oxidase prepared by any of several previously published methods which use Triton X-100 contains nine subunits. The enzyme isolate...

  17. Reexamining Michaelis-Menten Enzyme Kinetics for Xanthine Oxidase

    Science.gov (United States)

    Bassingthwaighte, James B.; Chinn, Tamara M.

    2013-01-01

    Abbreviated expressions for enzyme kinetic expressions, such as the Michaelis-Menten (M-M) equations, are based on the premise that enzyme concentrations are low compared with those of the substrate and product. When one does progress experiments, where the solute is consumed during conversion to form a series of products, the idealized conditions…

  18. Reexamining Michaelis-Menten Enzyme Kinetics for Xanthine Oxidase

    Science.gov (United States)

    Bassingthwaighte, James B.; Chinn, Tamara M.

    2013-01-01

    Abbreviated expressions for enzyme kinetic expressions, such as the Michaelis-Menten (M-M) equations, are based on the premise that enzyme concentrations are low compared with those of the substrate and product. When one does progress experiments, where the solute is consumed during conversion to form a series of products, the idealized conditions…

  19. Monoamine oxidase-inhibition and MPTP-induced neurotoxicity in the non-human primate: comparison of rasagiline (TVP 1012) with selegiline.

    Science.gov (United States)

    Kupsch, A; Sautter, J; Götz, M E; Breithaupt, W; Schwarz, J; Youdim, M B; Riederer, P; Gerlach, M; Oertel, W H

    2001-01-01

    The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been shown to induce parkinsonism in man and non-human primates. Monoamine-oxidase B (MAO-B) has been reported to be implicated in both MPTP-induced parkinsonism and Parkinson's disease, since selegiline (L-deprenyl), an irreversible MAO-B inhibitor, prevents MPTP-induced neurotoxicity in numerous species including mice, goldfish and drosophyla. However, one disadvantage of this substance relates to its metabolism to (-)-methamphetamine and (-)-amphetamine. Rasagiline (R-(+)-N-propyl-1-aminoindane) is a novel irrevesible MAO-B-inhibitor, which is not metabolized to metamphetamine and/or amphetamine. The present study compared the effects of high doses of selegiline and rasagiline (10 mg/kg body weight s.c.) on MPTP-induced dopaminergic neurotoxicity in a non-human primate (Callithrix jacchus) model of PD. Groups of four monkeys were assigned to the following six experimental groups: Group I: Saline, Group II: Selegiline/Saline, Group III: Rasagiline/Saline, Group IV: MPTP/Saline, Group V: Rasagiline/MPTP, Group VI: Selegiline/MPTP. Daily treatment with MAO-B-inhibitors (either rasagiline or selegiline, 10 mg/kg body weight s.c.) was initiated four days prior to MPTP-exposure (MPTP-HCl, 2 mg/kg body weight subcutaneously, separated by an interval of 24 hours for a total of four days) and was continued until the end of the experiment, i.e. 7 days after the cessation of the MPTP-injections, when animals were sacrificed. MPTP-treatment caused distinct behavioural, histological, and biochemical alterations: 1. significant reduction of motor activity assessed by clinical rating and by computerized locomotor activity measurements; 2. substantial loss (approx. 40%) of dopaminergic (tyrosine-hydroxylase-positive) cells in the substantia nigra, pars compacta; and 3. putaminal dopamine depletion of 98% and its metabolites DOPAC (88%) and HVA (96%). Treatment with either rasagiline or selegiline markedly

  20. Lower Monoamine Oxidase-A Total Distribution Volume in Impulsive and Violent Male Offenders with Antisocial Personality Disorder and High Psychopathic Traits: An [(11)C] Harmine Positron Emission Tomography Study.

    Science.gov (United States)

    Kolla, Nathan J; Matthews, Brittany; Wilson, Alan A; Houle, Sylvain; Bagby, R Michael; Links, Paul; Simpson, Alexander I; Hussain, Amina; Meyer, Jeffrey H

    2015-10-01

    Antisocial personality disorder (ASPD) often presents with highly impulsive, violent behavior, and pathological changes in the orbitofrontal cortex (OFC) and ventral striatum (VS) are implicated. Several compelling reasons support a relationship between low monoamine oxidase-A (MAO-A), an enzyme that regulates neurotransmitters, and ASPD. These include MAO-A knockout models in rodents evidencing impulsive aggression and positron emission tomography (PET) studies of healthy subjects reporting associations between low brain MAO-A levels and greater impulsivity or aggression. However, a fundamental gap in the literature is that it is unknown whether brain MAO-A levels are low in more severe, clinical disorders of impulsivity, such as ASPD. To address this issue, we applied [(11)C] harmine PET to measure MAO-A total distribution volume (MAO-A VT), an index of MAO-A density, in 18 male ASPD participants and 18 age- and sex-matched controls. OFC and VS MAO-A VT were lower in ASPD compared with controls (multivariate analysis of variance (MANOVA): F2,33=6.8, P=0.003; OFC and VS MAO-A VT each lower by 19%). Similar effects were observed in other brain regions: prefrontal cortex, anterior cingulate cortex, dorsal putamen, thalamus, hippocampus, and midbrain (MANOVA: F7,28=2.7, P=0.029). In ASPD, VS MAO-A VT was consistently negatively correlated with self-report and behavioral measures of impulsivity (r=-0.50 to -0.52, all P-values<0.05). This study is the first to demonstrate lower brain MAO-A levels in ASPD. Our results support an important extension of preclinical models of impulsive aggression into a human disorder marked by pathological aggression and impulsivity.

  1. Lower Monoamine Oxidase-A Total Distribution Volume in Impulsive and Violent Male Offenders with Antisocial Personality Disorder and High Psychopathic Traits: An [11C] Harmine Positron Emission Tomography Study

    Science.gov (United States)

    Kolla, Nathan J; Matthews, Brittany; Wilson, Alan A; Houle, Sylvain; Michael Bagby, R; Links, Paul; Simpson, Alexander I; Hussain, Amina; Meyer, Jeffrey H

    2015-01-01

    Antisocial personality disorder (ASPD) often presents with highly impulsive, violent behavior, and pathological changes in the orbitofrontal cortex (OFC) and ventral striatum (VS) are implicated. Several compelling reasons support a relationship between low monoamine oxidase-A (MAO-A), an enzyme that regulates neurotransmitters, and ASPD. These include MAO-A knockout models in rodents evidencing impulsive aggression and positron emission tomography (PET) studies of healthy subjects reporting associations between low brain MAO-A levels and greater impulsivity or aggression. However, a fundamental gap in the literature is that it is unknown whether brain MAO-A levels are low in more severe, clinical disorders of impulsivity, such as ASPD. To address this issue, we applied [11C] harmine PET to measure MAO-A total distribution volume (MAO-A VT), an index of MAO-A density, in 18 male ASPD participants and 18 age- and sex-matched controls. OFC and VS MAO-A VT were lower in ASPD compared with controls (multivariate analysis of variance (MANOVA): F2,33=6.8, P=0.003; OFC and VS MAO-A VT each lower by 19%). Similar effects were observed in other brain regions: prefrontal cortex, anterior cingulate cortex, dorsal putamen, thalamus, hippocampus, and midbrain (MANOVA: F7,28=2.7, P=0.029). In ASPD, VS MAO-A VT was consistently negatively correlated with self-report and behavioral measures of impulsivity (r=−0.50 to −0.52, all P-values<0.05). This study is the first to demonstrate lower brain MAO-A levels in ASPD. Our results support an important extension of preclinical models of impulsive aggression into a human disorder marked by pathological aggression and impulsivity. PMID:26081301

  2. Resistance of the golden hamster to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-neurotoxicity is not only related with low levels of cerebral monoamine oxidase-B.

    Science.gov (United States)

    Rodríguez, Sebastián; Ito, Tsuyoshi; He, Xi Jun; Uchida, Kazuyuki; Nakayama, Hiroyuki

    2013-01-01

    1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been proved to be a potent neurotoxin on dopaminergic neurons inducing most of the symptoms and cerebral lesions observed in the idiopathic Parkinson's disease (PD). Although there is a substantial body of theory and researches about the effects of MPTP on susceptible mice and nonhuman primates, there are only few studies in resistant animals, such as golden hamsters (GH). The low levels of cerebral monoamine oxidase-B (MAO-B) enzyme have been proposed as the cause of the GH insensitivity to MPTP. The aim of this study was to elucidate whether MAO-B is the only factor which confer GH resistance to MPTP. Neither loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) nor cell death in the subventricular zone (SVZ) were found in female GH in response to an acute intraperitoneal (ip) MPTP treatment. To prove the role of MAO-B in the MPTP-resistance, female and male GH was intracerebroventricularly (icv) injected with either MPTP or 1-methyl-4-phenylpyridinum (MPP(+)). Neither depletion in the number of dopaminergic neurons, nor astrogliosis, cell death in the SVZ of female and male GH were registered after an icv treatment with MPTP or MPP(+). Furthermore, we demonstrated that MAO-B is located predominantly within the endothelial cells in the blood brain barrier (BBB), but not in the astroglia. The present results raise the possibility that, in GH, other mechanisms, apart from the low levels of regional MAO-B, confer resistance to MPTP and its metabolites.

  3. The effects of monoamine oxidase inhibitors on the ejaculatory response induced by 5-methoxy-N,N-dimethyltryptamine in the rat.

    Science.gov (United States)

    Rényi, L.

    1986-01-01

    The ejaculatory response and other components of the 5-hydroxytryptamine (5-HT) behavioural syndrome induced by 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) (3 mg kg-1, i.p.) were studied following single and repeated treatment of rats with eight different monoamine oxidase (MAO) inhibitors. Single and repeated treatment with the 5-HT agonist 5-MeODMT, and with low doses of the potent releaser of 5-HT, p-chloroamphetamine (PCA) were also included in the study. Repeated but not single treatment with 5-MeODMT reduced strongly but reversibly the ejaculatory response and the behavioural responses. Repeated but not single treatment with the nonselective and irreversible MAO inhibitors nialamide and pargyline reduced markedly the ejaculatory response but only slightly the 5-HT behavioural responses. Repeated treatment with the irreversible MAO-B inhibitor (-)-deprenyl, with the irreversible MAO-A inhibitor, clorgyline, with the reversible MAO-A inhibitor moclobemide, and with low doses of PCA did not affect either of the responses. Repeated but not single combined treatment with clorgyline plus PCA caused an almost complete blockade of all the four responses. The selective and reversible MAO-A inhibitors (as well as 5-HT releasers) amiflamine, alpha-ethyltryptamine, and alpha-methyltryptamine reduced markedly the ejaculatory response after both single and repeated treatments. The behavioural responses were blocked only after repeated treatment. It is concluded that single and repeated treatments of rats with different MAO inhibitors do not produce a common alteration in 5-HT2 receptor functions. Repeated treatment with 5-MeODMT caused a blockade of 75-95% of the ejaculatory response and 5-HT behavioural responses.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3091132

  4. 1-[2-(4-Benzyloxyphenoxy)Ethyl]Imidazole inhibits monoamine oxidase B and protects against neuronal loss and behavioral impairment in rodent models of Parkinson's disease.

    Science.gov (United States)

    Chung, Jin Yong; Lee, Ji Won; Ryu, Choon Ho; Min, Hye Kyung; Yoon, Yeo Jin; Lim, Mi Jung; Park, Cheol Hyoung

    2015-08-01

    Monoamine oxidase B (MAO-B) is well known as a therapeutic target for Parkinson's disease (PD). MAO-B inhibitors retain antiparkinsonism abilities to improve motor function and prevent neuronal loss by decreasing dopamine metabolism and oxidative stress in the brain. From the study to find novel antiparkinsonism drugs that can inhibit MAO-B activity, neuronal loss, and behavioral deficits in the mouse model of PD, we identified that 1-[2-(4-benzyloxyphenoxy)ethyl]imidazole (BPEI) or safinamide strongly and selectively inhibited MAO-B activities in a dose-dependent manner (IC50 of BPEI and safinamide for MAO-B were 0.016 and 0.0021 µM and for MAO-A were 70.0 and 370 µM, respectively). In ex vivo studies after an administration (30 mg/kg, i.p.) of BPEI or safinamide to normal mice, the MAO-B activity in the brain was reduced by up to 90.6% or 82.4% at 1.0 hr. BPEI (20 mg/kg, i.p.) or safinamide (20 mg/kg, i.p.) significantly reversed the behavioral impairments, dopamine levels in the striatum, and neuronal loss in the substantia nigra of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice compared with the MPTP-alone-treated group. In the 6-hydroxydopamine-induced PD rat model, behavioral improvement by levodopa sparing activity was observed in the BPEI- or safinamide-treated (20 mg/kg, i.p.) rats. Moreover, BPEI revealed additional curative activities for nonmotor symptoms of PD such as pain, anxiety, epilepsy, and depression in rodent disease models. Therefore, BPEI has broad therapeutic potential for treating motor symptoms via strong and selective inhibitory effects on MAO-B, with additional benefits for comorbid symptoms in PD. © 2015 Wiley Periodicals, Inc.

  5. Morphological alterations and acetylcholinesterase and monoamine oxidase inhibition in liver of zebrafish exposed to Aphanizomenon flos-aquae DC-1 aphantoxins.

    Science.gov (United States)

    Zhang, De Lu; Zhang, Jing; Hu, Chun Xiang; Wang, Gao Hong; Li, Dun Hai; Liu, Yong Ding

    2014-12-01

    Aphanizomenon flos-aquae is a cyanobacterium that produces neurotoxins or paralytic shellfish poisons (PSPs) called aphantoxins, which present threats to environmental safety and human health via eutrophication of water bodies worldwide. Although the molecular mechanisms of this neurotoxin have been studied, many questions remain unsolved, including those relating to in vivo hepatic neurotransmitter inactivation, physiological detoxification and histological and ultrastructural alterations. Aphantoxins extracted from the natural strain of A. flos-aquae DC-1 were analyzed by high-performance liquid chromatography. The main components were gonyautoxins 1 and 5 (GTX1, GTX5) and neosaxitoxin (neoSTX), which comprised 34.04%, 21.28%, and 12.77% respectively. Zebrafish (Danio rerio) were exposed intraperitoneally to 5.3 or 7.61 μg STX equivalents (eq)/kg (low and high doses, respectively) of A. flos-aquae DC-1 aphantoxins. Morphological alterations and changes in neurotransmitter conduction functions of acetylcholinesterase (AChE) and monoamine oxidase (MAO) in zebrafish liver were detected at different time points 1-24h post-exposure. Aphantoxin significantly enhanced hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and histological and ultrastructural damage in zebrafish liver at 3-12 h post-exposure. Toxin exposure increased the reactive oxygen species content and reduced total antioxidative capacity in zebrafish liver, suggesting oxidative stress. AChE and MAO activities were significantly inhibited, suggesting neurotransmitter inactivation/conduction function abnormalities in zebrafish liver. All alterations were dose- and time-dependent. Overall, the results indicate that aphantoxins/PSPs induce oxidative stress through inhibition of AChE and MAO activities, leading to neurotoxicity in zebrafish liver. The above parameters may be useful as bioindicators for investigating aphantoxins/PSPs and cyanobacterial blooms in nature

  6. Glyceraldehyde-3-phosphate dehydrogenase-monoamine oxidase B-mediated cell death-induced by ethanol is prevented by rasagiline and 1-R-aminoindan.

    Science.gov (United States)

    Ou, Xiao-Ming; Lu, Deyin; Johnson, Chandra; Chen, Kevin; Youdim, Moussa B H; Rajkowska, Grazyna; Shih, Jean C

    2009-08-01

    The inhibitors of monoamine oxidase B (MAO B) are effectively used as therapeutic drugs for neuropsychiatric and neurodegenerative diseases. However, their mechanism of action is not clear, since the neuroprotective effect of MAO B inhibitors is associated with the blockage of glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-death cascade, rather than the inhibition of MAO B. Here, we provide evidence that GAPDH potentiates the ethanol-induced activity of MAO B and brain cell toxicity. The levels of nuclear GAPDH and MAO B activity are significantly increased in brain-derived cell lines upon 75 mM ethanol-induced cell death. Over-expression of GAPDH in cells enhances ethanol-induced cell death, and also increases the ethanol-induced activation of MAO B. In contrast, the MAO B inhibitors rasagiline and selegiline (0.25 nM) and the rasagiline metabolite, 1-R-aminoindan (1 muM) decreases the ethanol-induced MAO B, prevents nuclear translocation of GAPDH and reduces cell death. In addition, GAPDH interacts with transforming growth factor-beta-inducible early gene (TIEG2), a transcriptional activator for MAO B, and this interaction is increased in the nucleus by ethanol but reduced by MAO B inhibitors and 1-R-aminoindan. Furthermore, silencing TIEG2 using RNAi significantly reduces GAPDH-induced MAO B upregulation and neurotoxicity. In summary, ethanol-induced cell death, attenuated by MAO B inhibitors, may result from disrupting the movement of GAPDH with the transcriptional activator into the nucleus and secondly inhibit MAO B gene expression. Thus, the neuroprotective effects of rasagiline or 1-R-aminoindan on ethanol-induced cell death mediated by a novel GAPDH-MAO B pathway may provide a new insight in the treatment of neurobiological diseases including alcohol-use disorders.

  7. G protein-coupled receptor kinase-2 (GRK-2) regulates serotonin metabolism through the monoamine oxidase AMX-2 in Caenorhabditis elegans.

    Science.gov (United States)

    Wang, Jianjun; Luo, Jiansong; Aryal, Dipendra K; Wetsel, William C; Nass, Richard; Benovic, Jeffrey L

    2017-04-07

    G protein-coupled receptors (GPCRs) regulate many animal behaviors. GPCR signaling is mediated by agonist-promoted interactions of GPCRs with heterotrimeric G proteins, GPCR kinases (GRKs), and arrestins. To further elucidate the role of GRKs in regulating GPCR-mediated behaviors, we utilized the genetic model system Caenorhabditis elegans Our studies demonstrate that grk-2 loss-of-function strains are egg laying-defective and contain low levels of serotonin (5-HT) and high levels of the 5-HT metabolite 5-hydroxyindole acetic acid (5-HIAA). The egg laying defect could be rescued by the expression of wild type but not by catalytically inactive grk-2 or by the selective expression of grk-2 in hermaphrodite-specific neurons. The addition of 5-HT or inhibition of 5-HT metabolism also rescued the egg laying defect. Furthermore, we demonstrate that AMX-2 is the primary monoamine oxidase that metabolizes 5-HT in C. elegans, and we also found that grk-2 loss-of-function strains have abnormally high levels of AMX-2 compared with wild-type nematodes. Interestingly, GRK-2 was also found to interact with and promote the phosphorylation of AMX-2. Additional studies reveal that 5-HIAA functions to inhibit egg laying in a manner dependent on the 5-HT receptor SER-1 and the G protein GOA-1. These results demonstrate that GRK-2 modulates 5-HT metabolism by regulating AMX-2 function and that 5-HIAA may function in the SER-1 signaling pathway. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Association between monoamine oxidase B A644G polymorphism and Parkinson's disease risk: a meta-analysis in the Chinese population.

    Science.gov (United States)

    Liu, J J; Wang, W; Meng, M; Liang, C S; Zhang, J W

    2016-07-14

    Although various individual studies have evaluated the correlation between monoamine oxidase B (MAOB), polymorphism, and Parkinson's disease (PD), the results remain inconclusive. Therefore, we performed a meta-analysis in the Chinese population to provide comprehensive data on the association between the MAOB polymorphism and PD. Eligible studies were identified via databases such as PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure, and Chinese Biology Medicine, throughout November 2015. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strengths of these associations. Eight studies documenting a total of 1385 cases of PD and 1426 controls were included in this meta-analysis. Overall, no significant association was found between the MAOB A644G polymorphism and PD risk in the Chinese population. However, in subgroup analyses, where results were stratified by geographical areas and source of controls, increased risk for PD in Northern China was observed (allele A vs G: OR = 1.33, 95%CI = 1.11-1.58; AA vs GG: OR = 1.46, 95%CI = 1.09-1.97; AA + AG vs GG: OR = 1.42, 95%CI = 1.06-1.90). Similarly, population-based studies also showed significant association between the MAOB A644G polymorphism and PD risk among different populations (allele A vs G: OR = 1.29, 95%CI = 1.11-1.51; AA vs GG: OR = 1.41, 95%CI = 1.09-1.82; AA + AG vs GG: OR = 1.34, 95%CI = 1.04- 1.71). In conclusion, this meta-analysis provided evidence that the MAOB A644G polymorphism may contribute to PD development in Northern China. Further studies conducted in other ethnic groups are required for definite conclusions.

  9. Comparison of Monoamine Oxidase Inhibitors in Decreasing Production of the Autotoxic Dopamine Metabolite 3,4-Dihydroxyphenylacetaldehyde in PC12 Cells.

    Science.gov (United States)

    Goldstein, David S; Jinsmaa, Yunden; Sullivan, Patti; Holmes, Courtney; Kopin, Irwin J; Sharabi, Yehonatan

    2016-02-01

    According to the catecholaldehyde hypothesis, the toxic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL) contributes to the loss of nigrostriatal dopaminergic neurons in Parkinson's disease. Monoamine oxidase-A (MAO-A) catalyzes the conversion of intraneuronal dopamine to DOPAL and may serve as a therapeutic target. The "cheese effect"-paroxysmal hypertension evoked by tyramine-containing foodstuffs-limits clinical use of irreversible MAO-A inhibitors. Combined MAO-A/B inhibition decreases DOPAL production in rat pheochromocytoma PC12 cells, but whether reversible MAO-A inhibitors or MAO-B inhibitors decrease endogenous DOPAL production is unknown. We compared the potencies of MAO inhibitors in attenuating DOPAL production and examined possible secondary effects on dopamine storage, constitutive release, synthesis, and auto-oxidation. Catechol concentrations were measured in cells and medium after incubation with the irreversible MAO-A inhibitor clorgyline, three reversible MAO-A inhibitors, or the MAO-B inhibitors selegiline or rasagiline for 180 minutes. Reversible MAO-A inhibitors were generally ineffective, whereas clorgyline (1 nM), rasagiline (500 nM), and selegiline (500 nM) decreased DOPAL levels in the cells and medium. All three drugs also increased dopamine and norepinephrine, decreased 3,4-dihydroxyphenylalanine, and increased cysteinyl-dopamine concentrations in the medium, suggesting increased vesicular uptake and constitutive release, decreased dopamine synthesis, and increased dopamine spontaneous oxidation. In conclusion, clorgyline, rasagiline, and selegiline decrease production of endogenous DOPAL. At relatively high concentrations, the latter drugs probably lose their selectivity for MAO-B. Possibly offsetting increased formation of potentially toxic oxidation products and decreased formation of DOPAL might account for the failure of large clinical trials of MAO-B inhibitors to demonstrate slowing of neurodegeneration in Parkinson

  10. The effects of child maltreatment on early signs of antisocial behavior: genetic moderation by tryptophan hydroxylase, serotonin transporter, and monoamine oxidase A genes.

    Science.gov (United States)

    Cicchetti, Dante; Rogosch, Fred A; Thibodeau, Eric L

    2012-08-01

    Gene-environment interaction effects in predicting antisocial behavior in late childhood were investigated among maltreated and nonmaltreated low-income children (N = 627, M age = 11.27). Variants in three genes were examined: tryptophan hydroxylase 1 (TPH1), serotonin transporter linked polymorphic region (5-HTTLPR), and monoamine oxidase A (MAOA) upstream variable number tandem repeat. In addition to child maltreatment status, we considered the impact of maltreatment subtypes, developmental timing of maltreatment, and chronicity. Indicators of antisocial behavior were obtained from self-, peer, and adult counselor reports. In a series of analyses of covariance, child maltreatment and its parameters demonstrated strong main effects on early antisocial behavior as assessed by all report forms. Genetic effects operated primarily in the context of gene-environment interactions, moderating the impact of child maltreatment on outcomes. Across the three genes, among nonmaltreated children no differences in antisocial behavior were found based on genetic variation. In contrast, among maltreated children specific polymorphisms of TPH1, 5-HTTLPR, and MAOA were each related to heightened self-report of antisocial behavior; the interaction of 5-HTTLPR and developmental timing of maltreatment also indicated more severe antisocial outcomes for children with early onset and recurrent maltreatment based on genotype. TPH1 and 5-HTTLPR interacted with maltreatment subtype to predict peer reports of antisocial behavior; genetic variation contributed to larger differences in antisocial behavior among abused children. The TPH1 and 5-HTTLPR polymorphisms also moderated the effects of maltreatment subtype on adult reports of antisocial behavior; again, the genetic effects were strongest for children who were abused. In addition, TPH1 moderated the effect of developmental timing of maltreatment and chronicity on adult reports of antisocial behavior. The findings elucidate how genetic

  11. Fabrication and optimisation of optical biosensor using alcohol oxidase enzyme to evaluate detection of formaldehyde

    Science.gov (United States)

    Rachim, A.; Sari, A. P.; Nurlely, Fauzia, V.

    2017-07-01

    In this study, a new and simple biosensor base on alcohol oxidase (AOX)-enzyme for detecting formaldehyde in aqueous solutions has been successfully fabricated. The alcohol oxidase (AOX) enzyme was immobilized on poly-n-butyl acrylic-co-N-acryloxysuccinimide (nBA-NAS) membrane containing chromoionophore. The chemical reaction between AOX and formaldehyde generates a colour change of chromoionophore detected by optical absorbance measured in UV Vis. This paper focuses on the concentration optimization of buffer phosphate solution, response time, the quantity of enzyme and the measurement of the detection range of biosensors. The result shows that the optimum concentration and pH of buffer phosphate solution is 0.05 M and pH 7, respectively. The optimum response time is 3 min, the optimum unit of enzyme for biosensor is 1 unit/sample and the detection range of biosensor is 0.264 mM with R2 = 0.9421.

  12. Multipotent cholinesterase/monoamine oxidase inhibitors for the treatment of Alzheimer’s disease: design, synthesis, biochemical evaluation, ADMET, molecular modeling, and QSAR analysis of novel donepezil-pyridyl hybrids

    Directory of Open Access Journals (Sweden)

    Bautista-Aguilera OM

    2014-10-01

    Full Text Available Oscar M Bautista-Aguilera,1,* Gerard Esteban,2,* Mourad Chioua,1 Katarina Nikolic,3 Danica Agbaba,3 Ignacio Moraleda,4 Isabel Iriepa,4 Elena Soriano,5 Abdelouahid Samadi,1 Mercedes Unzeta,2 José Marco-Contelles1 1Laboratory of Medicinal Chemistry (Institute of General Organic Chemistry [IQOG], National Research Council [CSIC], Madrid, Spain; 2Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Autonomous Barcelona University, Barcelona, Spain; 3Institute of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia; 4Department of Organic Chemistry, Faculty of Pharmacy, University of Alcalá, Ctra Barcelona, Alcalá de Henares, Spain; 5Synthesis, and Structure of Organic Compounds (SEPCO (IQOG, CSIC, Madrid, Spain *These authors have equally contributed to this work Abstract: The design, synthesis, and biochemical evaluation of donepezil-pyridyl hybrids (DPHs as multipotent cholinesterase (ChE and monoamine oxidase (MAO inhibitors for the potential treatment of Alzheimer’s disease (AD is reported. The 3D-quantitative structure-activity relationship study was used to define 3D-pharmacophores for inhibition of MAO A/B, acetylcholinesterase (AChE, and butyrylcholinesterase (BuChE enzymes and to design DPHs as novel multi-target drug candidates with potential impact in the therapy of AD. DPH14 (­Electrophorus electricus AChE [EeAChE]: half maximal inhibitory concentration [IC50] =1.1±0.3 nM; equine butyrylcholinesterase [eqBuChE]: IC50 =600±80 nM was 318-fold more potent for the inhibition of AChE, and 1.3-fold less potent for the inhibition of BuChE than the reference compound ASS234. DPH14 is a potent human recombinant BuChE (hBuChE inhibitor, in the same range as DPH12 or DPH16, but 13.1-fold less potent than DPH15 for the inhibition of human recombinant AChE (hAChE. Compared with donepezil, DPH14 is almost equipotent for the inhibition of hAChE, and 8.8-fold more potent for h

  13. Influence of protonation on substrate and inhibitor interactions at the active site of human monoamine oxidase-A.

    Science.gov (United States)

    Zapata-Torres, Gerald; Fierro, Angelica; Miranda-Rojas, Sebastian; Guajardo, Carlos; Saez-Briones, Patricio; Salgado, J Cristian; Celis-Barros, Cristian

    2012-05-25

    Although substrate conversion mediated by human monoaminooxidase (hMAO) has been associated with the deprotonated state of their amine moiety, data regarding the influence of protonation on substrate binding at the active site are scarce. Thus, in order to assess protonation influence, steered molecular dynamics (SMD) runs were carried out. These simulations revealed that the protonated form of the substrate serotonin (5-HT) exhibited stronger interactions at the protein surface compared to the neutral form. The latter displayed stronger interactions in the active site cavity. These observations support the possible role of the deprotonated form in substrate conversion. Multigrid docking studies carried out to rationalize the role of 5-HT protonation in other sites besides the active site indicated two energetically favored docking sites for the protonated form of 5-HT on the enzyme surface. These sites seem to be interconnected with the substrate/inhibitor cavity, as revealed by the tunnels observed by means of CAVER program. pK(a) calculations in the surface loci pointed to Glu³²⁷, Asp³²⁸, His⁴⁸⁸, and Asp¹³² as candidates for a possible in situ deprotonation step. Docking analysis of a group of inhibitors (structurally related to substrates) showed further interactions with the same two docking access sites. Interestingly, the protonated/deprotonated amine moiety of almost all compounds attained different docking poses in the active site, none of them oriented to the flavin moiety, thus producing a more variable and less productive orientations to act as substrates. Our results highlight the role of deprotonation in facilitating substrate conversion and also might reflect the necessity of inhibitor molecules to adopt specific orientations to achieve enzyme inhibition.

  14. Differential expression of serotonin, tryptophan hydroxylase and monoamine oxidase A in the mammary gland of the Myotis velifer bat.

    Directory of Open Access Journals (Sweden)

    Cristián Vela Hinojosa

    Full Text Available The mammary gland has long drawn the attention of the scientific community due to the limited knowledge of some fundamental aspects involved in the control of its function. Myotis velifer, a microchiropteran species, provides an interesting model to study some of the regulatory factors involved in the control of the mammary gland cycle. Having an asynchronous, monoestrous reproductive pattern, female M. velifer bats undergo drastic morphological changes of the breast during the reproductive cycle. Current research on non-chiropteran mammals indicates that serotonin (5-HT plays a major role in the intraluminal volume homeostasis of the mammary gland during lactation; however, an analysis of both the expression and localization of the main components of the serotonergic system in the bat mammary gland is lacking. Thus, the objectives of the present study were: to describe the gross and histological anatomy of the mammary gland of M. velifer to establish the lactation period for this species; to analyze the distribution and expression of the main serotonergic components in the mammary tissues of these bats under the physiological conditions of lactation, involution and the resting phase; and to provide information on the involvement of 5-HT in the regulation of the physiological function of this organ. To assess the expression and localization of serotonergic components, multiple immunofluorescence, Western blot and HPLC methods were used. 5-HT and the enzyme that catalyzes its synthesis (TPH were located in both myoepithelial and luminal epithelial cells, while the enzyme responsible for the catabolism of this neurohormone (MAO A was found in luminal epithelial cells as well as in secreted products. We also found an increased expression of serotonergic components during lactation, indicating that elements of the serotonergic system may play an important role in lactation in this species of bat in a way similar to that of other mammal species.

  15. Season-controlled changes in biochemical constituents and oxidase enzyme activities in tomato (Lycopersicon esculentum Mill.).

    Science.gov (United States)

    Sen, Supatra; Mukherji, S

    2009-07-01

    Season-controlled changes in biochemical constituents viz. carotenoids (carotene and xanthophyll) and pectic substances along with IAA-oxidase and polyphenol oxidase (PPO) enzyme activities were estimated/assayed in leaves of Lycopersicon esculentum Mill. (tomato) in two developmental stages--pre-flowering (35 days after sowing) and post-flowering (75 days after sowing) in three different seasons--summer rainy and winter Carotenoid content along with pectic substances were highest in winter and declined significantly in summer followed by rainy i.e. winter > summer > rainy. Carotenoid content was significantly higher in the pre-flowering as compared to post-flowering in all three seasons while pectic substances increased in the post-flowering as compared to pre-flowering throughout the annual cycle. IAA oxidase and PPO enzyme activities were enhanced in rainy and decreased sharply in summer and winter i.e. rainy > summer > winter. Both the enzymes exhibited higher activity in the post-flowering stage as compared to pre-flowering in all three seasons. These results indicate winter to be the most favourable season for tomato plants while rainy season environmental conditions prove to be unfavourable (stressful) with diminished content of carotenoid and pectic substances and low activities of IAA oxidase and PPO, ultimately leading to poor growth and productivity.

  16. Immobilization of the Enzyme Glucose Oxidase on Both Bulk and Porous SiO2 Surfaces

    Directory of Open Access Journals (Sweden)

    Fulvia Sinatra

    2008-09-01

    Full Text Available Silicon dioxide surfaces, both bulk and porous, were used to anchor the enzyme glucose oxidase. The immobilization protocol was optimized and the samples characterized using X-ray Photoelectron Spectroscopy, Energy Dispersive X-rays coupled to scanning electron microscopy and enzymatic activity measurements. We show that a uniform layer was obtained by activating the oxide before immobilization. X-ray Photoelectron Spectroscopy measurements carried out on bulk oxide showed that the silicon substrate signal was fully screened after the enzyme deposition showing the absence of uncovered surface regions. The enzyme presence was detected monitoring both the C 1s and N 1s signals. Finally, enzymatic activity measurements confirmed that the glucose oxidase activity was preserved after immobilization and maintained after three months of shelf life if the sample was properly stored. The importance of using porous silicon oxide to maximize the surface area was also evidenced.

  17. Carbon Nanotube Modified Screen Printed Electrodes: Pyranose Oxidase Immobilization Platform for Amperometric Enzyme Sensors

    Directory of Open Access Journals (Sweden)

    Dilek ODACI DEMIRKOL

    2017-03-01

    Full Text Available Here, a novel enzymatic biosensor was developed using multiwalled carbon nanotube including screen printed electrodes (MWCNT-SPE. Pyranose oxidase (PyOx was immobilized on the electrode surface by way of gelatin membrane and then cross-linked using glutaraldehyde. Glucose was detected at -0.7 V (vs. Ag/AgCl by watching consumed oxygen in enzymatic reaction after addition substrate. After optimization of pH and enzyme loading, the linearity was found in the range of 0.1–1.0 mM of glucose. After that, the effect of MCNT on the current was tested. Also the enzymatic biosensor including glucose oxidase instead of pyranose oxidase was prepared and the biosensor response followed for glucose. Furthermore, this system was tested for glucose analysis in soft drinks.

  18. The metal effect on the Polyphenol oxidase enzyme from borage(Trachystemon orientalis plant

    Directory of Open Access Journals (Sweden)

    Esma Hande Alıcı

    2013-06-01

    Full Text Available In this study, Polyphenol oxidase was extracted from Borage plant (Trachystemon orientalis and the crude extract was used for the assays. Its pH and temperature optima for 4-methyl cathecol were 5.0 and 5°C, respectively. Km of this enzyme was 4.55 mM for 4-methyl cathecol. We also found that the enzyme was activated by Fe3+, Mg2+, Zn2+, Cu2+, Ca2+, K+, but inhibited by Hg2+, Mn2+, Ni2+, Sn2+, Na+. Ba2+, Al3+ and Pb2+ metal ions both activated and inhibited the enzyme at different concentrations.

  19. Pharmacokinetic interactions between monoamine oxidase A inhibitor harmaline and 5-methoxy-N,N-dimethyltryptamine, and the impact of CYP2D6 status.

    Science.gov (United States)

    Jiang, Xi-Ling; Shen, Hong-Wu; Mager, Donald E; Yu, Ai-Ming

    2013-05-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT or street name "5-MEO") is a newer designer drug belonging to a group of naturally occurring indolealkylamines. Our recent study has demonstrated that coadministration of monoamine oxidase A (MAO-A) inhibitor harmaline (5 mg/kg) increases systemic exposure to 5-MeO-DMT (2 mg/kg) and active metabolite bufotenine. This study is aimed at delineating harmaline and 5-MeO-DMT pharmacokinetic (PK) interactions at multiple dose levels, as well as the impact of CYP2D6 that affects harmaline PK and determines 5-MeO-DMT O-demethylation to produce bufotenine. Our data revealed that inhibition of MAO-A-mediated metabolic elimination by harmaline (2, 5, and 15 mg/kg) led to a sharp increase in systemic and cerebral exposure to 5-MeO-DMT (2 and 10 mg/kg) at all dose combinations. A more pronounced effect on 5-MeO-DMT PK was associated with greater exposure to harmaline in wild-type mice than CYP2D6-humanized (Tg-CYP2D6) mice. Harmaline (5 mg/kg) also increased blood and brain bufotenine concentrations that were generally higher in Tg-CYP2D6 mice. Surprisingly, greater harmaline dose (15 mg/kg) reduced bufotenine levels. The in vivo inhibitory effect of harmaline on CYP2D6-catalyzed bufotenine formation was confirmed by in vitro study using purified CYP2D6. Given these findings, a unified PK model including the inhibition of MAO-A- and CYP2D6-catalyzed 5-MeO-DMT metabolism by harmaline was developed to describe blood harmaline, 5-MeO-DMT, and bufotenine PK profiles in both wild-type and Tg-CYP2D6 mouse models. This PK model may be further employed to predict harmaline and 5-MeO-DMT PK interactions at various doses, define the impact of CYP2D6 status, and drive harmaline-5-MeO-DMT pharmacodynamics.

  20. Modification of 5-methoxy-N,N-dimethyltryptamine-induced hyperactivity by monoamine oxidase A inhibitor harmaline in mice and the underlying serotonergic mechanisms.

    Science.gov (United States)

    Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

    2016-06-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are indolealkylamine (IAA) drugs often abused together. Our recent studies have revealed the significant effects of co-administered harmaline, a monoamine oxidase inhibitor (MAOI), on 5-MeO-DMT pharmacokinetics and thermoregulation. This study was to delineate the impact of harmaline and 5-MeO-DMT on home-cage activity in mouse models, as well as the contribution of serotonin (5-HT) receptors. Home-cage activities of individual animals were monitored automatically in the home cages following implantation of telemetry transmitters and administration of various doses of IAA drugs and 5-HT receptor antagonists. Area under the effect curve (AUEC) of mouse activity values were calculated by trapezoidal rule. High dose of harmaline (15mg/kg, ip) alone caused an early-phase (0-45min) hypoactivity in mice that was fully attenuated by 5-HT1A receptor antagonist WAY-100635, whereas a late-phase (45-180min) hyperactivity that was reduced by 5-HT2A receptor antagonist MDL-100907. 5-MeO-DMT (10 and 20mg/kg, ip) alone induced biphasic effects, an early-phase (0-45min) hypoactivity that was completely attenuated by WAY-100635, and a late-phase (45-180min) hyperactivity that was fully suppressed by MDL-100907. Interestingly, co-administration of MAOI harmaline (2-15mg/kg) with a subthreshold dose of 5-MeO-DMT (2mg/kg) induced excessive hyperactivities at late phase (45-180min) that could be abolished by either WAY-100635 or MDL-100907. Co-administration of MAOI with 5-MeO-DMT provokes excessive late-phase hyperactivity, which involves the activation of both 5-HT1A and 5-HT2A receptors. Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  1. Morphological alterations and acetylcholinesterase and monoamine oxidase inhibition in liver of zebrafish exposed to Aphanizomenon flos-aquae DC-1 aphantoxins

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, De Lu, E-mail: deluzh@163.com [Department of Lifescience and Biotechnology, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070 (China); Zhang, Jing [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Hu, Chun Xiang, E-mail: cxhu@ihb.ac.cn [Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072 (China); Wang, Gao Hong; Li, Dun Hai; Liu, Yong Ding [Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072 (China)

    2014-12-15

    Highlights: • Aphantoxins induced zebrafish hepatic physiological and morphological changes. • AChE and MAO inhibition reflected abnormality of neurotransmitter inactivation. • ROS advance and T-AOC reduction suggested oxidative stress. • ALT, AST, histological and ultrastructural alterations indicated hepatic damage. - Abstract: Aphanizomenon flos-aquae is a cyanobacterium that produces neurotoxins or paralytic shellfish poisons (PSPs) called aphantoxins, which present threats to environmental safety and human health via eutrophication of water bodies worldwide. Although the molecular mechanisms of this neurotoxin have been studied, many questions remain unsolved, including those relating to in vivo hepatic neurotransmitter inactivation, physiological detoxification and histological and ultrastructural alterations. Aphantoxins extracted from the natural strain of A. flos-aquae DC-1 were analyzed by high-performance liquid chromatography. The main components were gonyautoxins 1 and 5 (GTX1, GTX5) and neosaxitoxin (neoSTX), which comprised 34.04%, 21.28%, and 12.77% respectively. Zebrafish (Danio rerio) were exposed intraperitoneally to 5.3 or 7.61 μg STX equivalents (eq)/kg (low and high doses, respectively) of A. flos-aquae DC-1 aphantoxins. Morphological alterations and changes in neurotransmitter conduction functions of acetylcholinesterase (AChE) and monoamine oxidase (MAO) in zebrafish liver were detected at different time points 1–24 h post-exposure. Aphantoxin significantly enhanced hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and histological and ultrastructural damage in zebrafish liver at 3–12 h post-exposure. Toxin exposure increased the reactive oxygen species content and reduced total antioxidative capacity in zebrafish liver, suggesting oxidative stress. AChE and MAO activities were significantly inhibited, suggesting neurotransmitter inactivation/conduction function abnormalities in zebrafish

  2. The monoamine oxidase-A inhibitor clorgyline promotes a mesenchymal-to-epithelial transition in the MDA-MB-231 breast cancer cell line.

    Science.gov (United States)

    Satram-Maharaj, Tamara; Nyarko, Jennifer N K; Kuski, Kelly; Fehr, Kelsey; Pennington, Paul R; Truitt, Luke; Freywald, Andrew; Lukong, Kiven Erique; Anderson, Deborah H; Mousseau, Darrell D

    2014-12-01

    Monoamine oxidase-A (MAO-A) dysfunction has been historically associated with depression. Recently, depression as well as altered MAO-A expression have both been associated with a poor prognosis in cancers, although the mechanism involved remains ambiguous. For example, MAO-A mRNA is repressed across cancers, yet MAO-A protein and levels of serotonin, a substrate of MAO-A implicated in depression, are paradoxically increased in malignancies, including breast cancer. The effect of clorgyline (CLG), a selective inhibitor of MAO-A, on malignant behaviour, expression of transitional markers, and biochemical correlates was examined in two human breast carcinoma cell lines, i.e. the epithelial, oestrogen receptor (ER)-positive MCF-7 cell line and the post-EMT (mesenchymal), ER-negative MDA-MB-231 cell line. CLG exerted little effect on malignant behaviour in MCF-7 cells, but inhibited proliferation and anchorage-independent growth, and increased invasiveness and active migration of MDA-MB-231 cells. CLG induced the expression of the mesenchymal marker vimentin in MCF-7 cells, but not in MDA-MB-231 cells. In contrast, CLG induced the epithelial protein marker E-cadherin in both cell lines, with a more robust effect in MDA-MB-231 cells (where a nuclear E-cadherin signal was also detected). This effect appears to be independent of any canonical Snai1-mediated regulation of E-cadherin mRNA expression. CLG interfered with the β-catenin/[phospho]GSK-3β complex as well as the E-cadherin/β-catenin complex in both cell lines cells, but, again, the effect was more robust in MDA-MB-231 cells. Parallel studies revealed a general lack of effect of CLG on the ER-negative, epithelial Au565 breast cancer cell line. Thus, any effect of CLG on metastatic behaviours appears to rely on the cell's EMT status rather than on the cell's ER status. These data suggest that inactivation of MAO-A triggers a mesenchymal-to-epithelial transition in MDA-MB-231 cells via a non-canonical mechanism

  3. Significance of membrane bioreactor design on the biocatalytic performance of glucose oxidase and catalase: Free vs. immobilized enzyme systems

    DEFF Research Database (Denmark)

    Morthensen, Sofie Thage; Meyer, Anne S.; Jørgensen, Henning

    2017-01-01

    -induced enzyme immobilization in the porous support of an ultrafiltration membrane was used as strategy for entrapment of glucose oxidase and catalase. The biocatalytic productivity of the membrane reactor was found to be highly related to the oxygen availability, which in turn depended on the reactor......Membrane separation of xylose and glucose can be accomplished via oxidation of glucose to gluconic acid by enzymatic glucose oxidase catalysis. Oxygen for this reaction can be supplied via decomposition of hydrogen peroxide by enzymatic catalase catalysis. In order to maximize the biocatalytic...... productivity of glucose oxidase and catalase (gluconic acid yield per total amount of enzyme) the following system set-ups were compared: immobilization of glucose oxidase alone; co-immobilization of glucose oxidase and catalase; glucose oxidase and catalase free in the membrane bioreactor. Fouling...

  4. The respiratory burst oxidase of human neutrophils. Further studies of the purified enzyme.

    Science.gov (United States)

    Glass, G A; DeLisle, D M; DeTogni, P; Gabig, T G; Magee, B H; Markert, M; Babior, B M

    1986-10-05

    A superoxide-forming oxidase from activated human neutrophil membranes was solubilized by two slightly different methods, then purified by "dye-affinity" chromatography. Kinetic studies of the purified preparations gave Vmax values of 5-10 mumol of O-2/min/mg of protein, and Km values for NADH and NADPH that were in reasonable agreement with values determined previously using particulate and crude solubilized preparations of the respiratory burst oxidase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed prominent bands at 67, 48, and 32 kDa, together with some minor contaminants, whereas gel electrophoresis under non-denaturing conditions gave a single major band that when eluted and re-electrophoresed in the presence of sodium dodecyl sulfate showed bands at 67, 48, 32 kDa. We believe that all three bands represent oxidase components. The flavin content of the purified enzyme was 20.4 +/- 2.0 S.E. pmol of FAD/microgram of protein, whereas heme averaged 0.1 +/- 0.02 pmol/microgram and ubiquinone could not be detected. Assuming that the enzyme is composed of one 67-kDa subunit, one 48-kDa subunit, and one 32-kDa subunit (i.e. that its molecular mass is approximately 150 kDa), it can be calculated to have a turnover number of 700-1500 min-1, in agreement with a value reported previously for oxidase in a particulate O-2-forming system (Cross, A. R., Parkinson, J. F., and Jones, O. T. G. (1985) Biochem. J. 226, 881-884), and to contain the following quantities of redox carriers (mol/mol): FAD, 3.0; heme, 0.015; ubiquinone, less than 0.06. It remains to be determined whether this preparation represents the complete respiratory burst oxidase or is only the pyridine nucleotide dehydrogenating component of a more complex enzyme.

  5. Kinetic and solvent deuterium isotope effects in the oxidation of putrescine catalysed by enzyme diamine oxidase.

    Science.gov (United States)

    Pałka, Katarzyna; Szymańska, Jolanta; Kańska, Marianna

    2013-01-01

    In this study, the kinetic isotope effects and solvent isotope effects in the reaction of the deamination of [(1R)-(2)H ] putrescine--catalysed by enzyme diamine oxidase (EC 1.4.3.6)--were determined using a non-competitive spectroscopic method. Putrescine, stereospecifically labelled with deuterium, was obtained by enzymatic decarboxylation of l-ornithine that was carried out in a fully deuteriated incubation medium.

  6. The four aldehyde oxidases of Drosophila melanogaster have different gene expression patterns and enzyme substrate specificities.

    Science.gov (United States)

    Marelja, Zvonimir; Dambowsky, Miriam; Bolis, Marco; Georgiou, Marina L; Garattini, Enrico; Missirlis, Fanis; Leimkühler, Silke

    2014-06-15

    In the genome of Drosophila melanogaster, four genes coding for aldehyde oxidases (AOX1-4) were identified on chromosome 3. Phylogenetic analysis showed that the AOX gene cluster evolved via independent duplication events in the vertebrate and invertebrate lineages. The functional role and the substrate specificity of the distinct Drosophila AOX enzymes is unknown. Two loss-of-function mutant alleles in this gene region, low pyridoxal oxidase (Po(lpo)) and aldehyde oxidase-1 (Aldox-1(n1)) are associated with a phenotype characterized by undetectable AOX enzymatic activity. However, the genes involved and the corresponding mutations have not yet been identified. In this study we characterized the activities, substrate specificities and expression profiles of the four AOX enzymes in D. melanogaster. We show that the Po(lpo)-associated phenotype is the consequence of a structural alteration of the AOX1 gene. We identified an 11-bp deletion in the Po(lpo) allele, resulting in a frame-shift event, which removes the molybdenum cofactor domain of the encoded enzyme. Furthermore, we show that AOX2 activity is detectable only during metamorphosis and characterize a Minos-AOX2 insertion in this developmental gene that disrupts its activity. We demonstrate that the Aldox-1(n1) phenotype maps to the AOX3 gene and AOX4 activity is not detectable in our assays.

  7. Understanding the Molecular Determinant of Reversible Human Monoamine Oxidase B Inhibitors Containing 2H-chromen-2-One Core: Structure-Based and Ligand-Based Derived 3-D QSAR Predictive Models.

    Science.gov (United States)

    Mladenovic, Milan; Patsilinakos, Alexandros; Pirolli, Adele; Sabatino, Manuela; Ragno, Rino

    2017-03-14

    Monoamine oxidase B (MAO B) catalyzes the oxidative deamination of aryalkylamines neurotransmitters with concomitant reduction of oxygen to hydrogen peroxide. Consequently, the enzyme's malfunction can induce oxidative damage to mitochondrial DNA and mediates development of Parkinson's disease. Thus, MAO B emerges as a promising target for developing pharmaceuticals potentially useful to treat this vicious neurodegenerative condition. Aiming to contribute to the development of drugs with the reversible mechanism of MAO B inhibition only, herein, an extended in silico-in vitro procedure for the selection of novel MAO B inhibitors is demonstrated, including: (1) definition of optimized and validated structure-based (SB) 3-D QSAR models derived from available co-crystallized inhibitor-MAO B complexes; (2) elaboration of structure-activity relationships (SAR) features for either irreversible or reversible MAO B inhibitors to characterize and improve coumarin-based inhibitor activity (Protein Data Bank ID: 2V61) as the most potent reversible lead compound; (3) definition of structure-based (SB) and ligand-based (LB) alignment rules assessments by which virtually any untested potential MAO B inhibitor might be evaluated; (4) predictive ability validation of the best 3-D QSAR model through SB/LB modeling of four coumarin-based external test sets (267 compounds); (5) design and SB/LB alignment of novel coumarin-based scaffolds experimentally validated through synthesis and biological evaluation in vitro. Due to the wide range of molecular diversity within the 3-D QSARs training set and derived features, the selected N probe-derived 3-D QSAR model proves to be a valuable tool for virtual screening (VS) of novel MAO B inhibitors and a platform for design, synthesis and evaluation of novel active structures. Accordingly, six highly active and selective MAO B inhibitors (picomolar to low nanomolar range of activity) were disclosed as a result of rational SB/LB 3-D QSAR design

  8. NADPH oxidases in lung biology and pathology: host defense enzymes, and more.

    Science.gov (United States)

    van der Vliet, Albert

    2008-03-15

    The deliberate production of reactive oxygen species (ROS) by phagocyte NADPH oxidase is widely appreciated as a critical component of antimicrobial host defense. Recently, additional homologs of NADPH oxidase (NOX) have been discovered throughout the animal and plant kingdoms, which appear to possess diverse functions in addition to host defense, in cell proliferation, differentiation, and in regulation of gene expression. Several of these NOX homologs are also expressed within the respiratory tract, where they participate in innate host defense as well as in epithelial and inflammatory cell signaling and gene expression, and fibroblast and smooth muscle cell proliferation, in response to bacterial or viral infection and environmental stress. Inappropriate expression or activation of NOX/DUOX during various lung pathologies suggests their specific involvement in respiratory disease. This review summarizes the current state of knowledge regarding the general functional properties of mammalian NOX enzymes, and their specific importance in respiratory tract physiology and pathology.

  9. The elusive third subunit IIa of the bacterial B-type oxidases: the enzyme from the hyperthermophile Aquifex aeolicus.

    Directory of Open Access Journals (Sweden)

    Laurence Prunetti

    Full Text Available The reduction of molecular oxygen to water is catalyzed by complicated membrane-bound metallo-enzymes containing variable numbers of subunits, called cytochrome c oxidases or quinol oxidases. We previously described the cytochrome c oxidase II from the hyperthermophilic bacterium Aquifex aeolicus as a ba(3-type two-subunit (subunits I and II enzyme and showed that it is included in a supercomplex involved in the sulfide-oxygen respiration pathway. It belongs to the B-family of the heme-copper oxidases, enzymes that are far less studied than the ones from family A. Here, we describe the presence in this enzyme of an additional transmembrane helix "subunit IIa", which is composed of 41 amino acid residues with a measured molecular mass of 5105 Da. Moreover, we show that subunit II, as expected, is in fact longer than the originally annotated protein (from the genome and contains a transmembrane domain. Using Aquifex aeolicus genomic sequence analyses, N-terminal sequencing, peptide mass fingerprinting and mass spectrometry analysis on entire subunits, we conclude that the B-type enzyme from this bacterium is a three-subunit complex. It is composed of subunit I (encoded by coxA(2 of 59000 Da, subunit II (encoded by coxB(2 of 16700 Da and subunit IIa which contain 12, 1 and 1 transmembrane helices respectively. A structural model indicates that the structural organization of the complex strongly resembles that of the ba(3 cytochrome c oxidase from the bacterium Thermus thermophilus, the IIa helical subunit being structurally the lacking N-terminal transmembrane helix of subunit II present in the A-type oxidases. Analysis of the genomic context of genes encoding oxidases indicates that this third subunit is present in many of the bacterial oxidases from B-family, enzymes that have been described as two-subunit complexes.

  10. NADPH Oxidase Enzymes in Skin Fibrosis: Molecular Targets and Therapeutic Agents

    Science.gov (United States)

    Lev-Tov, Hadar; Jagdeo, Jared

    2013-01-01

    Fibrosis is characterized by the excessive deposition of extracellular matrix components eventually resulting in organ dysfunction and failure. In dermatology, fibrosis is the hallmark component of many skin diseases, including systemic sclerosis, graft versus host disease, hypertrophic scars, keloids, nephrogenic systemic fibrosis, porphyria cutanea tarda, restrictive dermopathy and other conditions. Fibrotic skin disorders may be debilitating and impair quality of life. There are few FDA-approved anti-fibrotic drugs; thus, research in this area is crucial in addressing this deficiency. Recent investigations elucidating the pathogenesis of skin fibrosis have implicated endogenous reactive oxygen species produced by the multicomponent nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) enzyme complex. In this review we discuss Nox enzymes and their role in skin fibrosis. An overview of the Nox enzyme family is presented and their role in the pathogenesis of skin fibrosis is discussed. The mechanisms that Nox enzymes influence specific skin fibrotic disorders are also reviewed. Finally, we describe the therapeutic approaches to ameliorate skin fibrosis by directly targeting Nox enzymes with the use of statins, p47phox subunit modulators, or GKT137831, a competitive inhibitor of Nox enzymes. Nox enzymes can also be targeted indirectly via scavenging ROS with antioxidants. We believe that Nox modulators are worthy of further investigation and have the potential to transform the management of skin fibrosis by dermatologists. PMID:24155025

  11. NADPH oxidase enzymes in skin fibrosis: molecular targets and therapeutic agents.

    Science.gov (United States)

    Babalola, Olubukola; Mamalis, Andrew; Lev-Tov, Hadar; Jagdeo, Jared

    2014-05-01

    Fibrosis is characterized by the excessive deposition of extracellular matrix components eventually resulting in organ dysfunction and failure. In dermatology, fibrosis is the hallmark component of many skin diseases, including systemic sclerosis, graft-versus-host disease, hypertrophic scars, keloids, nephrogenic systemic fibrosis, porphyria cutanea tarda, restrictive dermopathy and other conditions. Fibrotic skin disorders may be debilitating and impair quality of life. There are few FDA-approved anti-fibrotic drugs; thus, research in this area is crucial in addressing this deficiency. Recent investigations elucidating the pathogenesis of skin fibrosis have implicated endogenous reactive oxygen species produced by the multicomponent nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) enzyme complex. In this review, we discuss Nox enzymes and their role in skin fibrosis. An overview of the Nox enzyme family is presented and their role in the pathogenesis of skin fibrosis is discussed. The mechanisms by which Nox enzymes influence specific fibrotic skin disorders are also reviewed. Finally, we describe the therapeutic approaches to ameliorate skin fibrosis by directly targeting Nox enzymes with the use of statins, p47phox subunit modulators, or GKT137831, a competitive inhibitor of Nox enzymes. Nox enzymes can also be targeted indirectly via scavenging ROS with antioxidants. We believe that Nox modulators are worthy of further investigation and have the potential to transform the management of skin fibrosis by dermatologists.

  12. Fabrication of enzyme reactor utilizing magnetic porous polymer membrane for screening D-Amino acid oxidase inhibitors.

    Science.gov (United States)

    Jiang, Jun Fang; Qiao, Juan; Mu, Xiao Yu; Moon, Myeong Hee; Qi, Li

    2017-04-01

    In this work, a unique D-amino acid oxidase reactor for enhanced enzymolysis efficiency is presented. A kind of magnetic polymer matrices, composed of iron oxide nanoparticles and porous polymer membrane (poly styrene-co-maleic anhydride), was prepared. With covalent bonding D-Amino acid oxidase on the surface of the matrices and characterization of scanning electron microscope and vibrating sample magnetometer, it demonstrated that the membrane enzyme reactor was successfully constructed. The enzymolysis efficiency of the enzyme reactor was evaluated and the apparent Michaelis-Menten constants of D-Amino acid oxidase were determined (Km was 1.10mM, Vmax was 23.8mMmin(-1)) by a chiral ligand exchange capillary electrophoresis protocol with methionine as the substrate. The results indicated that the enzyme reactor could exhibit good stability and excellent reusability. Importantly, because the enzyme and the substrate could be confined into the pores of the matrices, the enzyme reactor displayed the improved enzymolysis efficiency due to the confinement effect. Further, the prepared enzyme reactor was applied for D-Amino acid oxidase inhibitors screening. It has displayed that the proposed protocol could pave a new way for fabrication of novel porous polymer membrane based enzyme reactors to screen enzyme inhibitors.

  13. Syntheses of 8-(phenoxymethyl)caffeine analogues and their evaluation as inhibitors of monoamine oxidase and as antagonists of the adenosine A2A receptor / Rozanne Harmse.

    OpenAIRE

    Harmse, Rozanne

    2013-01-01

    Background and rationale: Parkinson’s disease (PD) is a progressive, degenerative disorder of the central nervous system and is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta. The loss of functional dopamine in the striatum is thought to be responsible for the typical symptoms of PD. Cardinal features of PD include bradykinesia, muscular rigidity, resting tremor and impairment of postural balance. This study focuses on the inhibition of monoamine oxida...

  14. Effects of hexabromocyclododecane(HBCD) on monoamine neurotransmitters contents and monoamine oxidase activity of developmental rat brain%六溴环十二烷对发育期大鼠脑单胺类神经递质质量比及单胺氧化酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    刘芳; 冀秀玲; 赵文娟; 殷明; 蒋惠男; 张江

    2012-01-01

    通过研究发育期大鼠脑单胺类神经递质质量比及单胺氧化酶活性,探讨环境暴露水平的六溴环十二烷对发育期大鼠的神经毒性作用.选择10 μg/kg、50 μg/kg、100μg/kg、300 μg/kg的剂量对新生3d大鼠进行暴露,饲养42d后断头取脑组织,测定多巴胺(DA)、去甲肾上腺素(NE)、5-羟色胺(5-HT)的质量比及单胺氧化酶(MAO)的活性.结果表明,在10 - 100 μg/kg的暴露剂量范围,DA质量比随暴露剂量的升高而下降,NE质量比呈现上升趋势,5- HT质量比则极显著性升高(p <0.01);与此同时,MAO的活性随剂量增加而升高,在100μg/kg剂量出现显著性升高(p<0.05).而300μμg/kg的剂量作为较高暴露水平的参照,只对DA产生显著性影响(p<0.05).DA、5 - HT、NE的质量比及MAO活性的变化可能在大鼠的中枢神经系统的发育障碍中发挥了重要作用,并且环境暴露水平的HBCD对发育期大鼠脑具有低剂量高效应的毒性反应特征.%The paper is aimed to study the hexabromocyclododecane (HBCD) as a kind of brominated flame retardants extensively used in the industrial production. The spectrophotometry and enzyme-linked immunosorbent assay (ELISA) can be used for examining the contents of dopamine(DA), noradrenalin(NE) , 5-hydroxytryptamine(5- HT) and monoamine oxidase (MAO) activity when the sprague-dawley 3-day old rats were exposed to the different dosages (10μg/kg, 50 μg/kg, 100 fig/kg, 300 μg/kg body weight) of HBCD in a period of 42 days. The results of our experiments with the rats show that, compared with the controlled group, DA contents of 10 μg/kg and 300 μg/kg exposures tends to drop significantly(p < 0.05) , in a decreasing rate in a range of 10 - 100 μg/kg exposure doses. However, no significant changes were detected of NE. In addition, an increase trend can be found in the range of 10 μg/kg to 100 μg/kg doses, with the 5 - HT contents of 10 - 100 μg/kg exposures increased sig-nificantly(p < 0

  15. Performance of optical biosensor using alcohol oxidase enzyme for formaldehyde detection

    Science.gov (United States)

    Sari, A. P.; Rachim, A.; Nurlely, Fauzia, V.

    2017-07-01

    The recent issue in the world is the long exposure of formaldehyde which is can increase the risk of human health, therefore, that is very important to develop a device and method that can be optimized to detect the formaldehyde elements accurately, have a long lifetime and can be fabricated and produced in large quantities. A new and simple prepared optical biosensor for detection of formaldehyde in aqueous solutions using alcohol oxidase (AOX) enzyme was successfully fabricated. The poly-n-butyl acrylic-co-N-acryloxysuccinimide (nBA-NAS) membranes containing chromoionophore ETH5294 were used for immobilization of alcohol oxidase enzyme (AOX). Biosensor response was based on the colour change of chromoionophore as a result of enzymatic oxidation of formaldehyde and correlated with the detection concentration of formaldehyde. The performance of biosensor parameters were measured through the optical absorption value using UV-Vis spectrophotometer including the repeatability, reproducibility, selectivity and lifetime. The results showed that the prepared biosensor has good repeatability (RSD = 1.9 %) and good reproducibility (RSD = 2.1 %). The biosensor was selective formaldehyde with no disturbance by methanol, ethanol, and acetaldehyde, and also stable before 49 days and decrease by 41.77 % after 49 days.

  16. Preparation of immobilized glucose oxidase wafer enzyme on calcium-bentonite modified by surfactant

    Science.gov (United States)

    Widi, R. K.; Trisulo, D. C.; Budhyantoro, A.; Chrisnasari, R.

    2017-07-01

    Wafer glucose oxidase (GOx) enzymes was produced by addition of PAH (Poly-Allyamine Hydrochloride) polymer into immobilized GOx enzyme on modified-Tetramethylammonium Hydroxide (TMAH) 5%-calsium-bentonite. The use of surfactant molecul (TMAH) is to modify the surface properties and pore size distribution of the Ca-bentonite. These properties are very important to ensure GOx molecules can be bound on the Ca-bentonit surface to be immobilized. The addition of the polymer (PAH) is expected to lead the substrates to be adsorbed onto the enzyme. In this study, wafer enzymes were made in various concentration ratio (Ca-bentonite : PAH) which are 1:0, 1:1, 1:2 and 1:3. The effect of PAH (Poly-Allyamine Hydrochloride) polymer added with various ratios of concentrations can be shown from the capacitance value on LCR meter and enzyme activity using DNS method. The addition of the polymer (PAH) showed effect on the activity of GOx, it can be shown from the decreasing of capacitance value by increasing of PAH concentration.

  17. Enzyme precipitate coatings of glucose oxidase onto carbon paper for biofuel cell applications.

    Science.gov (United States)

    Fischback, Mike; Kwon, Ki Young; Lee, Inseon; Shin, Su Jeong; Park, Hyun Gyu; Kim, Byoung Chan; Kwon, Yongchai; Jung, Hee-Tae; Kim, Jungbae; Ha, Su

    2012-02-01

    Enzymatic biofuel cells (BFC) have a great potential as a small power source, but their practical applications are being hampered by short lifetime and low power density. This study describes the direct immobilization of glucose oxidase (GOx) onto the carbon paper in the form of highly stable and active enzyme precipitation coatings (EPCs), which can improve the lifetime and power density of BFCs. EPCs were fabricated directly onto the carbon paper via a three-step process: covalent attachment (CA), enzyme precipitation, and chemical crosslinking. GOx-immobilized carbon papers via the CA and EPC approaches were used as an enzyme anode and their electrochemical activities were tested under the BFC-operating mode. The BFCs with CA and EPC enzyme anodes produced the maximum power densities of 50 and 250 µW/cm(2) , respectively. The BFC with the EPC enzyme anode showed a stable current density output of >700 µA/cm(2) at 0.18 V under continuous operation for over 45 h. When a maple syrup was used as a fuel under ambient conditions, it also produced a stable current density of >10 µA/cm(2) at 0.18 V for over 25 h. It is anticipated that the direct immobilization of EPC on hierarchical-structured electrodes with a large surface area would further improve the power density of BFCs that can make their applications more feasible.

  18. Laccase versus laccase-like multi-copper oxidase: a comparative study of similar enzymes with diverse substrate spectra.

    Directory of Open Access Journals (Sweden)

    Renate Reiss

    Full Text Available Laccases (EC 1.10.3.2 are multi-copper oxidases that catalyse the one-electron oxidation of a broad range of compounds including substituted phenols, arylamines and aromatic thiols to the corresponding radicals. Owing to their broad substrate range, copper-containing laccases are versatile biocatalysts, capable of oxidizing numerous natural and non-natural industry-relevant compounds, with water as the sole by-product. In the present study, 10 of the 11 multi-copper oxidases, hitherto considered to be laccases, from fungi, plant and bacterial origin were compared. A substrate screen of 91 natural and non-natural compounds was recorded and revealed a fairly broad but distinctive substrate spectrum amongst the enzymes. Even though the enzymes share conserved active site residues we found that the substrate ranges of the individual enzymes varied considerably. The EC classification is based on the type of chemical reaction performed and the actual name of the enzyme often refers to the physiological substrate. However, for the enzymes studied in this work such classification is not feasible, even more so as their prime substrates or natural functions are mainly unknown. The classification of multi-copper oxidases assigned as laccases remains a challenge. For the sake of simplicity we propose to introduce the term "laccase-like multi-copper oxidase" (LMCO in addition to the term laccase that we use exclusively for the enzyme originally identified from the sap of the lacquer tree Rhus vernicifera.

  19. Enzyme precipitate coating of pyranose oxidase on carbon nanotubes and their electrochemical applications.

    Science.gov (United States)

    Kim, Jae Hyun; Hong, Sung-Gil; Wee, Youngho; Hu, Shuozhen; Kwon, Yongchai; Ha, Su; Kim, Jungbae

    2017-01-15

    Pyranose oxidase (POx), which doesn't have electrically non-conductive glycosylation moiety, was immobilized on carbon nanotubes (CNTs) via three different preparation methods: covalent attachment (CA), enzyme coating (EC) and enzyme precipitate coating (EPC). CA, EC and EPC of POx on CNTs were used to fabricate enzymatic electrodes for enzyme-based biosensors and biofuel cells. Improved enzyme loading of EPC resulted in 6.5 and 4.5 times higher activity per weight of CNTs than those of CA and EC, respectively. After 34 days at room temperature, EPC retained 65% of initial activity, while CA and EC maintained 9.2% and 26% of their initial activities, respectively. These results indicate that precipitation and crosslinking steps of EPC have an important role in maintaining enzyme activity. To demonstrate the feasibility of POx-based biosensors and biofuel cells, the enzyme electrodes were prepared using CA, EC, and EPC samples. In the case of biosensor, the sensitivities of the CA, EC, and EPC electrodes without BQ were measured to be 0.27, 0.76 and 3.7mA/M/cm(2), while CA, EC and EPC electrode with BQ showed 25, 25, and 60mA/M/cm(2) of sensitivities, respectively. The maximum power densities of biofuel cells using CA, EC and EPC electrodes without BQ were 41, 47 and 53µW/cm(2), while CA, EC and EPC electrodes with BQ showed 260, 330 and 500µW/cm(2), respectively. The POx immobilization and stabilization via the EPC approach can lead us to develop continuous glucose monitoring biosensors and high performing biofuel cells.

  20. Secreted fungal sulfhydryl oxidases: sequence analysis and characterisation of a representative flavin-dependent enzyme from Aspergillus oryzae

    Directory of Open Access Journals (Sweden)

    Faccio Greta

    2010-08-01

    Full Text Available Abstract Background Sulfhydryl oxidases are flavin-dependent enzymes that catalyse the formation of de novo disulfide bonds from free thiol groups, with the reduction of molecular oxygen to hydrogen peroxide. Sulfhydryl oxidases have been investigated in the food industry to remove the burnt flavour of ultraheat-treated milk and are currently studied as potential crosslinking enzymes, aiming at strengthening wheat dough and improving the overall bread quality. Results In the present study, potential sulfhydryl oxidases were identified in the publicly available fungal genome sequences and their sequence characteristics were studied. A representative sulfhydryl oxidase from Aspergillus oryzae, AoSOX1, was expressed in the fungus Trichoderma reesei. AoSOX1 was produced in relatively good yields and was purified and biochemically characterised. The enzyme catalysed the oxidation of thiol-containing compounds like glutathione, D/L-cysteine, beta-mercaptoethanol and DTT. The enzyme had a melting temperature of 57°C, a pH optimum of 7.5 and its enzymatic activity was completely inhibited in the presence of 1 mM ZnSO4. Conclusions Eighteen potentially secreted sulfhydryl oxidases were detected in the publicly available fungal genomes analysed and a novel proline-tryptophan dipeptide in the characteristic motif CXXC, where X is any amino acid, was found. A representative protein, AoSOX1 from A. oryzae, was produced in T. reesei in an active form and had the characteristics of sulfhydryl oxidases. Further testing of the activity on thiol groups within larger peptides and on protein level will be needed to assess the application potential of this enzyme.

  1. Evaluation of enzyme immobilization methods for paper-based devices--A glucose oxidase study.

    Science.gov (United States)

    Nery, Emilia Witkowska; Kubota, Lauro T

    2016-01-01

    Paper-based sensors gained almost explosive attention during the last few years. A large number of systems, often destined to resource limited settings is based on enzymatic reactions. Choice of an adequate immobilization method could significantly prolong the shelf-life of such sensors, especially in applications, where exposure to high temperatures during storage and transport is more than a threat. We are seeking to compare a variety of immobilization methods based on different phenomena (adsorption, entrapment in gel, microencapsulation, covalent linkage), with total of 33 methods tested. Glucose oxidase was used as a model enzyme. Enzymatic activity of immobilized samples was accompanied for a period of 24 weeks considering two sets of samples, one stored in 4 °C and other in ambient temperature.

  2. Direct electrical communication between chemically modified enzymes and metal electrodes. 1. Electron transfer from glucose oxidase to metal electrodes via electron relays, bound covalently to the enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Degani, Y.; Heller, A.

    1987-03-12

    Glucose-reduced glucose oxidase does not directly transfer electrons to conventional electrodes because the distance between its redox centers and the electrode surface exceeds, even on closest approach, the distance across which electrons are transferred at sufficient rates. Therefore, electrical communication between the redox centers of this enzyme and electrodes required either the presence, and diffusion to and from the enzyme's redox center, of O/sub 2/ and H/sub 2/O/sub 2/, or the presence of members of a redox couple, or the use of special electrodes like TTF/TCNQ. They show here that direct electrical communication between the redox center of a large enzyme molecule and a simple metal electrode can be established through chemical modification of the enzyme. When a sufficient number of electron-relaying centers are attached through covalent bonding to the protein of glucose oxidase, electrons are transferred from the enzyme's redox centers to relays that are closer to the periphery of the enzyme. Because some of the relays are located sufficiently close to the enzyme's surface, electrons are transferred at practical rates to the electrode. As a result, a glucose-concentration-dependent current flows in an electrochemical cell made with conventional electrodes when the electrolytic solution contains the relay-modified enzyme. Such a current does not flow when the solution contains the natural enzyme. Specifically, electrical communication is established between the FAD/FADH/sub 2/ centers of glucose oxidase and gold, platinum, or carbon electrodes through the covalent bonding of an average of 12 molecules of ferrocenecarboxylic acid per glucose oxidase molecule.

  3. Allosteric modulation of semicarbazide-sensitive amine oxidase activities in vitro by imidazoline receptor ligands

    OpenAIRE

    2004-01-01

    Evidence indicates that imidazoline I2 binding sites (I2BSs) are present on monoamine oxidase (MAO) and on soluble (plasma) semicarbazide-sensitive amine oxidase enzymes. The binding site on MAO has been described as a modulatory site, although no effects on activity are thought to have been observed as a result of ligands binding to these sites.We examined the effects in vitro of several imidazoline binding site ligands on activities of bovine plasma amine oxidase (BPAO) and porcine kidney d...

  4. Molecular evolution of the reactive oxygen-generating NADPH oxidase (Nox/Duox family of enzymes

    Directory of Open Access Journals (Sweden)

    Lambeth J David

    2007-07-01

    Full Text Available Abstract Background NADPH-oxidases (Nox and the related Dual oxidases (Duox play varied biological and pathological roles via regulated generation of reactive oxygen species (ROS. Members of the Nox/Duox family have been identified in a wide variety of organisms, including mammals, nematodes, fruit fly, green plants, fungi, and slime molds; however, little is known about the molecular evolutionary history of these enzymes. Results We assembled and analyzed the deduced amino acid sequences of 101 Nox/Duox orthologs from 25 species, including vertebrates, urochordates, echinoderms, insects, nematodes, fungi, slime mold amoeba, alga and plants. In contrast to ROS defense enzymes, such as superoxide dismutase and catalase that are present in prokaryotes, ROS-generating Nox/Duox orthologs only appeared later in evolution. Molecular taxonomy revealed seven distinct subfamilies of Noxes and Duoxes. The calcium-regulated orthologs representing 4 subfamilies diverged early and are the most widely distributed in biology. Subunit-regulated Noxes represent a second major subdivision, and appeared first in fungi and amoeba. Nox5 was lost in rodents, and Nox3, which functions in the inner ear in gravity perception, emerged the most recently, corresponding to full-time adaptation of vertebrates to land. The sea urchin Strongylocentrotus purpuratus possesses the earliest Nox2 co-ortholog of vertebrate Nox1, 2, and 3, while Nox4 first appeared somewhat later in urochordates. Comparison of evolutionary substitution rates demonstrates that Nox2, the regulatory subunits p47phox and p67phox, and Duox are more stringently conserved in vertebrates than other Noxes and Nox regulatory subunits. Amino acid sequence comparisons identified key catalytic or regulatory regions, as 68 residues were highly conserved among all Nox/Duox orthologs, and 14 of these were identical with those mutated in Nox2 in variants of X-linked chronic granulomatous disease. In addition to

  5. A sacrificial millipede altruistically protects its swarm using a drone blood enzyme, mandelonitrile oxidase.

    Science.gov (United States)

    Ishida, Yuko; Kuwahara, Yasumasa; Dadashipour, Mohammad; Ina, Atsutoshi; Yamaguchi, Takuya; Morita, Masashi; Ichiki, Yayoi; Asano, Yasuhisa

    2016-06-06

    Soldiers of some eusocial insects exhibit an altruistic self-destructive defense behavior in emergency situations when attacked by large enemies. The swarm-forming invasive millipede, Chamberlinius hualienensis, which is not classified as eusocial animal, exudes irritant chemicals such as benzoyl cyanide as a defensive secretion. Although it has been thought that this defensive chemical was converted from mandelonitrile, identification of the biocatalyst has remained unidentified for 40 years. Here, we identify the novel blood enzyme, mandelonitrile oxidase (ChuaMOX), which stoichiometrically catalyzes oxygen consumption and synthesis of benzoyl cyanide and hydrogen peroxide from mandelonitrile. Interestingly the enzymatic activity is suppressed at a blood pH of 7, and the enzyme is segregated by membranes of defensive sacs from mandelonitrile which has a pH of 4.6, the optimum pH for ChuaMOX activity. In addition, strong body muscle contractions are necessary for de novo synthesis of benzoyl cyanide. We propose that, to protect its swarm, the sacrificial millipede also applies a self-destructive defense strategy-the endogenous rupturing of the defensive sacs to mix ChuaMOX and mandelonitrile at an optimum pH. Further study of defensive systems in primitive arthropods will pave the way to elucidate the evolution of altruistic defenses in the animal kingdom.

  6. Subunit structure of bovine milk xanthine oxidase. Effect of limited cleavage by proteolytic enzymes on activity and structure.

    Science.gov (United States)

    Nagler, L G; Vartanyan, L S

    1976-03-18

    Bovine milk xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.2.3.2) has been purified by a modified method without the use of proteases, and its structure has been analyzed by polyacrylamide gel electrophoresis. Native xanthine oxidase is found to consist of only two polypeptide chains A with molecular weights of 150 000 each. These chains have NH2-terminal methionine. Limited proteolysis with trypsin, chymotrypsin, or subtilisin at pH 8 did not affect molecular weight and activities of the enzyme while each of the A chains was cleaved under these conditions to three fragments C, E, and F with molecular weights of 92 00, 42 000 and 20 000, respectively. These fragments remained bound to each other and were relatively resistant to subsequent proteolysis. The isolation of xanthine oxidase in the presence of pancreatin as described by Hart et al. (1970, Biochem. J. 116, 851) gives partially digested enzyme composed mainly of chains C, E (Mr 35 000) and a small component (Mr approx. 15 0-0). The action of subtilisin on xanthine oxidase at pH 11 resulted in complete digestion of E chains, FAD separation, and total loss of xanthine:oxygen oxidoreductase activity while xanthine:indophenol oxidoreductase activity was relatively little affected. The residual enzyme has a molecular weight of about 200 000, is composed mainly of two C chains (and may probably contain F and/or proteolytic fragments of low molecular weight), contains molybdenum, and does not contain FAD.

  7. Synthesis, crystal structures, molecular docking, in vitro monoamine oxidase-B inhibitory activity of transition metal complexes with 2-{4-[bis (4-fluorophenyl)methyl]piperazin-1-yl} acetic acid

    Science.gov (United States)

    Yang, Dan-dan; Wang, Riu; Zhu, Jin-long; Cao, Qi-yue; Qin, Jie; Zhu, Hai-liang; Qian, Shao-song

    2017-01-01

    Three novel complexes, [Cu(L)2(H2O)](1), [Zn(L)2(H2O)2]·CH3OH·1.5H2O(2), and [Ni(L)2(H2O)1.8]·CH3OH·1.2H2O (3) (HL = 2-{4-[bis(4-fluorophenyl)methyl]pipera-zin-1-yl} acetic acid), were synthesized and structurally determined by single-crystal X-ray diffraction. Molecular docking study preliminarily revealed that complex 1 had potential Monoamine oxidase B inhibitory activity. All acquired compounds were tested against rat brain MAO-B in vitro. In accordance with the result of calculation, it showed complex 1 (IC50 = 1.85 ± 0.31 μM) have good inhibitory activity against MAO-B at the same micromolar concentrations with positive control Iproniazid Phosphate (IP, IC50 = 7.59 ± 1.17 μM). These results indicated that complex 1 was a potent MAO-B inhibitor.

  8. Monoamine Oxidase A (MAOA) and Catechol-O-Methyltransferase (COMT) Gene Polymorphisms Interact with Maternal Parenting in Association with Adolescent Reactive Aggression but not Proactive Aggression: Evidence of Differential Susceptibility.

    Science.gov (United States)

    Zhang, Wenxin; Cao, Cong; Wang, Meiping; Ji, Linqin; Cao, Yanmiao

    2016-04-01

    To date, whether and how gene-environment (G × E) interactions operate differently across distinct subtypes of aggression remains untested. More recently, in contrast with the diathesis-stress hypothesis, an alternative hypothesis of differential susceptibility proposes that individuals could be differentially susceptible to environments depending on their genotypes in a "for better and for worse" manner. The current study examined interactions between monoamine oxidase A (MAOA) T941G and catechol-O-methyltransferase (COMT) Val158Met polymorphisms with maternal parenting on two types of aggression: reactive and proactive. Moreover, whether these potential G × E interactions would be consistent with the diathesis-stress versus the differential susceptibility hypothesis was tested. Within the sample of 1399 Chinese Han adolescents (47.2 % girls, M age = 12.32 years, SD = 0.50), MAOA and COMT genes both interacted with positive parenting in their associations with reactive but not proactive aggression. Adolescents with T alleles/TT homozygotes of MAOA gene or Met alleles of COMT gene exhibited more reactive aggression when exposed to low positive parenting, but less reactive aggression when exposed to high positive parenting. These findings provide the first evidence for distinct G × E interaction effects on reactive versus proactive aggression and lend further support for the differential susceptibility hypothesis.

  9. Proteomic and transcriptomic analysis of heart failure due to volume overload in a rat aorto-caval fistula model provides support for new potential therapeutic targets - monoamine oxidase A and transglutaminase 2

    Directory of Open Access Journals (Sweden)

    Petrak Jiri

    2011-11-01

    Full Text Available Abstract Background Chronic hemodynamic overloading leads to heart failure (HF due to incompletely understood mechanisms. To gain deeper insight into the molecular pathophysiology of volume overload-induced HF and to identify potential markers and targets for novel therapies, we performed proteomic and mRNA expression analysis comparing myocardium from Wistar rats with HF induced by a chronic aorto-caval fistula (ACF and sham-operated rats harvested at the advanced, decompensated stage of HF. Methods We analyzed control and failing myocardium employing iTRAQ labeling, two-dimensional peptide separation combining peptide IEF and nano-HPLC with MALDI-MS/MS. For the transcriptomic analysis we employed Illumina RatRef-12v1 Expression BeadChip. Results In the proteomic analysis we identified 2030 myocardial proteins, of which 66 proteins were differentially expressed. The mRNA expression analysis identified 851 differentially expressed mRNAs. Conclusions The differentially expressed proteins confirm a switch in the substrate preference from fatty acids to other sources in the failing heart. Failing hearts showed downregulation of the major calcium transporters SERCA2 and ryanodine receptor 2 and altered expression of creatine kinases. Decreased expression of two NADPH producing proteins suggests a decreased redox reserve. Overexpression of annexins supports their possible potential as HF biomarkers. Most importantly, among the most up-regulated proteins in ACF hearts were monoamine oxidase A and transglutaminase 2 that are both potential attractive targets of low molecular weight inhibitors in future HF therapy.

  10. A simple assay for mammalian spermine oxidase: a polyamine catabolic enzyme implicated in drug response and disease.

    Science.gov (United States)

    Goodwin, Andrew C; Murray-Stewart, Tracy R; Casero, Robert A

    2011-01-01

    Spermine oxidase (SMO), the most recently characterized polyamine metabolic enzyme, catalyzes the direct back-conversion of spermine to spermidine in an FAD-dependent reaction that also yields the byproducts hydrogen peroxide (H(2)O(2)) and 3-aminopropanal. These metabolites, particularly H(2)O(2), have been implicated in cytotoxic cellular responses to specific antitumor polyamine analogs, as well as in the inflammation-associated generation of DNA damage. This chapter describes a rapid, sensitive, and inexpensive method for the chemiluminescent measurement of SMO (or alternatively, N (1)-acetyl polyamine oxidase, APAO) enzyme activity in cultured cell lysates, without the need for radioactive reagents or the use of high performance liquid chromatography (HPLC). Specifically, H(2)O(2) production by SMO is coupled to chemiluminescence generated by the horseradish peroxidase-catalyzed oxidation of luminol. Detailed protocols for preparation of reagents, harvesting cell lysates, generation of a standard curve, assaying of samples, and calculation of SMO enzyme activity are presented.

  11. Boosting the oxidase mimicking activity of nanoceria by fluoride capping: rivaling protein enzymes and ultrasensitive F(-) detection.

    Science.gov (United States)

    Liu, Biwu; Huang, Zhicheng; Liu, Juewen

    2016-07-14

    Nanomaterial-based enzyme mimics (nanozymes) are currently a new forefront of chemical research. However, the application of nanozymes is limited by their low catalytic activity and low turnover numbers. Cerium dioxide nanoparticles (nanoceria) are among the few with oxidase activity. Herein, we report an interesting finding addressing their limitations. The oxidase activity of nanoceria is improved by over 100-fold by fluoride capping, making it more close to real oxidases. The turnover number reached 700 in 15 min, drastically improved from ∼15 turnovers for the naked particles. The mechanism is attributed to surface charge modulation and facilitated electron transfer by F(-) capping based on ζ-potential and free radical measurements. Ultrasensitive sensing of fluoride was achieved with a detection limit of 0.64 μM F(-) in water and in toothpastes, while no other tested anions can achieve the activity enhancement.

  12. Functional analysis of aldehyde oxidase using expressed chimeric enzyme between monkey and rat.

    Science.gov (United States)

    Itoh, Kunio; Asakawa, Tasuku; Hoshino, Kouichi; Adachi, Mayuko; Fukiya, Kensuke; Watanabe, Nobuaki; Tanaka, Yorihisa

    2009-01-01

    Aldehyde oxidase (AO) is a homodimer with a subunit molecular mass of approximately 150 kDa. Each subunit consists of about 20 kDa 2Fe-2S cluster domain storing reducing equivalents, about 40 kDa flavine adenine dinucleotide (FAD) domain and about 85 kDa molybdenum cofactor (MoCo) domain containing a substrate binding site. In order to clarify the properties of each domain, especially substrate binding domain, chimeric cDNAs were constructed by mutual exchange of 2Fe-2S/FAD and MoCo domains between monkey and rat. Chimeric monkey/rat AO was referred to one with monkey type 2Fe-2S/FAD domains and a rat type MoCo domain. Rat/monkey AO was vice versa. AO-catalyzed 2-oxidation activities of (S)-RS-8359 were measured using the expressed enzyme in Escherichia coli. Substrate inhibition was seen in rat AO and chimeric monkey/rat AO, but not in monkey AO and chimeric rat/monkey AO, suggesting that the phenomenon might be dependent on the natures of MoCo domain of rat. A biphasic Eadie-Hofstee profile was observed in monkey AO and chimeric rat/monkey AO, but not rat AO and chimeric monkey/rat AO, indicating that the biphasic profile might be related to the properties of MoCo domain of monkey. Two-fold greater V(max) values were observed in monkey AO than in chimeric rat/monkey AO, and in chimeric monkey/rat AO than in rat AO, suggesting that monkey has the more effective electron transfer system than rat. Thus, the use of chimeric enzymes revealed that 2Fe-2S/FAD and MoCo domains affect the velocity and the quantitative profiles of AO-catalyzed (S)-RS-8359 2-oxidation, respectively.

  13. Association of ventral striatum monoamine oxidase-A binding and functional connectivity in antisocial personality disorder with high impulsivity: A positron emission tomography and functional magnetic resonance imaging study.

    Science.gov (United States)

    Kolla, Nathan J; Dunlop, Katharine; Downar, Jonathan; Links, Paul; Bagby, R Michael; Wilson, Alan A; Houle, Sylvain; Rasquinha, Fawn; Simpson, Alexander I; Meyer, Jeffrey H

    2016-04-01

    Impulsivity is a core feature of antisocial personality disorder (ASPD) associated with abnormal brain function and neurochemical alterations. The ventral striatum (VS) is a key region of the neural circuitry mediating impulsive behavior, and low monoamine oxidase-A (MAO-A) level in the VS has shown a specific relationship to the impulsivity of ASPD. Because it is currently unknown whether phenotypic MAO-A markers can influence brain function in ASPD, we investigated VS MAO-A level and the functional connectivity (FC) of two seed regions, superior and inferior VS (VSs, VSi). Nineteen impulsive ASPD males underwent [(11)C] harmine positron emission tomography scanning to measure VS MAO-A VT, an index of MAO-A density, and resting-state functional magnetic resonance imaging that assessed the FC of bilateral seed regions in the VSi and VSs. Subjects also completed self-report impulsivity measures. Results revealed functional coupling of the VSs with bilateral dorsomedial prefrontal cortex (DMPFC) that was correlated with VS MAO-A VT (r=0.47, p=0.04), and functional coupling of the VSi with right hippocampus that was anti-correlated with VS MAO-A VT (r=-0.55, p=0.01). Additionally, VSs-DMPFC FC was negatively correlated with NEO Personality Inventory-Revised impulsivity (r=-0.49, p=0.03), as was VSi-hippocampus FC with Barratt Impulsiveness Scale-11 motor impulsiveness (r=-0.50, p=0.03). These preliminary results highlight an association of VS MAO-A level with the FC of striatal regions linked to impulsive behavior in ASPD and suggest that phenotype-based brain markers of ASPD have relevance to understanding brain function. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  14. Dual functions of transcription factors, transforming growth factor-beta-inducible early gene (TIEG)2 and Sp3, are mediated by CACCC element and Sp1 sites of human monoamine oxidase (MAO) B gene.

    Science.gov (United States)

    Ou, Xiao-Ming; Chen, Kevin; Shih, Jean C

    2004-05-14

    Monoamine oxidases (MAO) A and B catalyze the oxidative deamination of many biogenic and dietary amines. Abnormal expression of MAO has been implicated in several psychiatric and neurodegenerative disorders. Human MAO B core promoter (-246 to -99 region) consists of CACCC element flanked by two clusters of overlapping Sp1 sites. Here, we show that cotransfection with transforming growth factor (TGF)-beta-inducible early gene (TIEG)2 increased MAO B gene expression at promoter, mRNA, protein, and catalytic activity levels in both SH-SY5Y and HepG2 cells. Mutation of the CACCC element increased the MAO B promoter activity, and cotransfection with TIEG2 further increased the promoter activity, suggesting that CACCC was a repressor element. This increase was reduced when the proximal Sp1 overlapping sites was mutated. Similar interactions were found with Sp3. These results showed that TIEG2 and Sp3 were repressors at the CACCC element but were activators at proximal Sp1 overlapping sites of MAO B. Gel-shift and chromatin immunoprecipitation assays showed that TIEG2 and Sp3 bound directly to CACCC element and the proximal Sp1 sites in both synthetic oligonucleotides and natural MAO B core promoter. TIEG2 had a higher affinity to Sp1 sites than CACCC element, whereas Sp3 had an equal affinity to both elements. Thus, TIEG2 was an activator, but Sp3 had no effect on MAO B gene expression. This study provides new insights into MAO B gene expression and illustrates the complexity of gene regulation.

  15. Serological differences between the multiple amine oxidases of yeasts and comparison of the specificities of the purified enzymes from Candida utilis and Pichia pastoris.

    Science.gov (United States)

    Green, J; Haywood, G W; Large, P J

    1983-05-01

    1. Antiserum to purified methylamine oxidase of Candida boidinii formed precipitin lines (with spurs) in double-diffusion tests with crude extracts of methylamine-grown cells of the following yeast species: Candida nagoyaensis, Candida nemodendra, Hansenula minuta, Hansenula polymorpha and Pichia pinus. No cross-reaction was observed with extracts of Candida lipolytica, Candida steatolytica, Candida tropicalis, Candida utilis, Pichia pastoris, Sporobolomyces albo-rubescens, Sporopachydermia cereana or Trigonopsis variabilis. Quantitative enzyme assays enabled the relative titre of antiserum against the various methylamine oxidases to be determined. 2. The amine oxidases from two non-cross-reacting species, C. utilis and P. pastoris, were purified to near homogeneity. 3. The methylamine oxidases, despite their serological non-similarity, showed very similar catalytic properties to methylamine oxidase from C. boidinii. Their heat-stability, pH optima, molecular weights, substrate specificities and sensitivity to inhibitors are reported. 4. The benzylamine oxidases of C. utilis and P. pastoris both oxidized putrescine, and the latter enzyme failed to show any cross-reaction with antibody to C. boidinii methylamine oxidase. Benzylamine oxidase from C. boidinii itself also did not cross-react with antibody to methylamine oxidase. The heat-stability, molecular weights, substrate specificities and sensitivity to inhibitors of the benzylamine/putrescine oxidases are reported. 5. The benzylamine/putrescine oxidase of C. utilis differed only slightly from that of C. boidinii. 6. Benzylamine/putrescine oxidase from P. pastoris differed from the Candida enzymes in heat-stability, subunit molecular weight and substrate specificity. In particular it catalysed the oxidation of the primary amino groups of spermine, spermidine, lysine, ornithine and 1,2-diaminoethane, which are not substrates for either of the Candida benzylamine oxidases that have been purified. 7. Spermine and

  16. The effect of cultivation media and washing whole-cell biocatalysts on monoamine oxidase catalyzed oxidative desymmetrization of 3-azabicyclo[3,3,0]octane

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Zajkoska, Petra; Rebros, Martin

    2016-01-01

    It is well known that washing whole-cells containing enzyme activities after fermentation, but prior to biocatalysis can improve their activity in the subsequent reaction. In this paper, we quantify the impact of both the fermentation media and cell washing on the performance of whole-cell....... Unlike cells grown in LB medium, washing of the cells was essential for cells grown on TB medium. With TB media, washing the cells improved the final conversion by approximately a factor of two. Additionally, over 50-fold improvement was achieved in initial activity. A potential reason...... for this improvement in activity was identified to be the increase in transfer of substrates across the cell membrane as a result of cell washing. (C) 2015 Elsevier Inc. All rights reserved....

  17. Role of amine oxidase expression to maintain putrescine homeostasis in Rhodococcus opacus.

    Science.gov (United States)

    Foster, Alexander; Barnes, Nicole; Speight, Robert; Morris, Peter C; Keane, Mark A

    2013-04-10

    While applications of amine oxidases are increasing, few have been characterised and our understanding of their biological role and strategies for bacteria exploitation are limited. By altering the nitrogen source (NH4Cl, putrescine and cadaverine (diamines) and butylamine (monoamine)) and concentration, we have identified a constitutive flavin dependent oxidase (EC 1.4.3.10) within Rhodococcus opacus. The activity of this oxidase can be increased by over two orders of magnitude in the presence of aliphatic diamines. In addition, the expression of a copper dependent diamine oxidase (EC 1.4.3.22) was observed at diamine concentrations>1mM or when cells were grown with butylamine, which acts to inhibit the flavin oxidase. A Michaelis-Menten kinetic treatment of the flavin oxidase delivered a Michaelis constant (KM)=190μM and maximum rate (kcat)=21.8s(-1) for the oxidative deamination of putrescine with a lower KM (=60μM) and comparable kcat (=18.2s(-1)) for the copper oxidase. MALDI-TOF and genomic analyses have indicated a metabolic clustering of functionally related genes. From a consideration of amine oxidase specificity and sequence homology, we propose a putrescine degradation pathway within Rhodococcus that utilises oxidases in tandem with subsequent dehydrogenase and transaminase enzymes. The implications of PUT homeostasis through the action of the two oxidases are discussed with respect to stressors, evolution and application in microbe-assisted phytoremediation or bio-augmentation.

  18. Finding New Enzymes from Bacterial Physiology: A Successful Approach Illustrated by the Detection of Novel Oxidases in Marinomonas mediterranea

    Directory of Open Access Journals (Sweden)

    Antonio Sanchez-Amat

    2010-03-01

    Full Text Available The identification and study of marine microorganisms with unique physiological traits can be a very powerful tool discovering novel enzymes of possible biotechnological interest. This approach can complement the enormous amount of data concerning gene diversity in marine environments offered by metagenomic analysis, and can help to place the activities associated with those sequences in the context of microbial cellular metabolism and physiology. Accordingly, the detection and isolation of microorganisms that may be a good source of enzymes is of great importance. Marinomonas mediterranea, for example, has proven to be one such useful microorganism. This Gram-negative marine bacterium was first selected because of the unusually high amounts of melanins synthesized in media containing the amino acid L-tyrosine. The study of its molecular biology has allowed the cloning of several genes encoding oxidases of biotechnological interest, particularly in white and red biotechnology. Characterization of the operon encoding the tyrosinase responsible for melanin synthesis revealed that a second gene in that operon encodes a protein, PpoB2, which is involved in copper transfer to tyrosinase. This finding made PpoB2 the first protein in the COG5486 group to which a physiological role has been assigned. Another enzyme of interest described in M. mediterranea is a multicopper oxidase encoding a membrane-associated enzyme that shows oxidative activity on a wide range of substrates typical of both laccases and tyrosinases. Finally, an enzyme very specific for L-lysine, which oxidises this amino acid in epsilon position and that has received a new EC number (1.4.3.20, has also been described for M. mediterranea. Overall, the studies carried out on this bacterium illustrate the power of exploring the physiology of selected microorganisms to discover novel enzymes of biotechnological relevance.

  19. Purine-induced expression of urate oxidase and enzyme activity in Atlantic salmon (Salmo salar). Cloning of urate oxidase liver cDNA from three teleost species and the African lungfish Protopterus annectens.

    Science.gov (United States)

    Andersen, Øivind; Aas, Turid S; Skugor, Stanko; Takle, Harald; van Nes, Solveig; Grisdale-Helland, Barbara; Helland, Ståle J; Terjesen, Bendik F

    2006-07-01

    The peroxisomal enzyme urate oxidase plays a pivotal role in the degradation of purines in both prokaryotes and eukaryotes. However, knowledge about the purine-induced expression of the encoding gene is lacking in vertebrates. These are the first published sequences of fish urate oxidase, which were predicted from PCR amplified liver cDNAs of Atlantic salmon (Salmo salar), Atlantic cod (Gadus morhua), Atlantic halibut (Hippoglossus hippoglossus) and African lungfish (Protopterus annectens). Sequence alignment of different vertebrate urate oxidases revealed amino acid substitutions of putative functional importance in the enzyme of chicken and lungfish. In the adult salmon, expression of urate oxidase mRNA predominated in liver, but was also identified in several nonhepatic organs including brain, but not in skeletal muscle and kidney. Juvenile salmon fed diets containing bacterial protein meal (BPM) rich in nucleic acids showed a significant increase in liver urate oxidase enzyme activity, and urea concentrations in plasma, muscle and liver were elevated. Whereas salmon fed the 18% BPM diet showed a nonsignificant increase in liver mRNA levels of urate oxidase compared with the 0% BPM-fed fish, no further increase in mRNA levels was found in fish receiving 36% BPM. The discrepancy between urate oxidase mRNA and enzyme activity was explained by rapid mRNA degradation or alternatively, post-translational control of the activity. Although variable plasma and liver levels of urate were detected, the substrate increased only slightly in 36% BPM-fed fish, indicating that the uricolytic pathway of Atlantic salmon is intimately regulated to handle high dietary purine levels.

  20. Radiosynthesis and in vivo evaluation of [{sup 11}C]-labelled pyrrole-2-carboxamide derivates as novel radioligands for PET imaging of monoamine oxidase A

    Energy Technology Data Exchange (ETDEWEB)

    De Bruyne, Sylvie [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium); La Regina, Giuseppe [Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universita di Roma, I-00185 Rome (Italy); Staelens, Steven [IBITECH-Medisip, Ghent University-IBBT, 9000 Ghent (Belgium); Wyffels, Leonie [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium); Deleye, Steven [IBITECH-Medisip, Ghent University-IBBT, 9000 Ghent (Belgium); Silvestri, Romano [Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Universita di Roma, I-00185 Rome (Italy); De Vos, Filip [Laboratory for Radiopharmacy, Ghent University, 9000 Ghent (Belgium)], E-mail: filipx.devos@ugent.be

    2010-05-15

    Introduction: Since MAO-A is an enzyme involved in the metabolism of neurotransmitters, fluctuations in MAO-A functionality are associated with psychiatric and neurological disorders as well as with tobacco addiction and behaviour. This study reports the radiolabelling of two [{sup 11}C]-labelled pyrrole-2-carboxamide derivates, RS 2315 and RS 2360, along with the characterization of their in vivo properties. Methods: The radiolabelling of [{sup 11}C]-RS 2315 and [{sup 11}C]-RS 2360 was accomplished by alkylation of their amide precursors with [{sup 11}C]CH{sub 3}I. Biodistribution, blocking and metabolite studies of both tracers were performed in NMRI mice. Finally, a PET study in Sprague-Dawley rats was performed for [{sup 11}C]-RS 2360. Results: Both tracers were obtained in a radiochemical yield of approximately 30% with radiochemical purity of >98%. Biodistribution studies showed high brain uptake followed by rapid brain clearance for both radiotracers. In the brain, [{sup 11}C]-RS 2360 was more stable than [{sup 11}C]-RS 2315. Blocking studies in mice could not demonstrate specificity of [{sup 11}C]-RS 2315 towards MAO-A or MAO-B. The blocking and imaging study with [{sup 11}C]-RS 2360 on the other hand indicated specific binding in MAO-A at the earliest time points. Conclusions: [{sup 11}C]-RS 2315 displayed a high nonspecific binding and is therefore not suitable for visualization of MAO-A in vivo. [{sup 11}C]-RS 2360 on the other hand has potential for mapping MAO-A since specific binding is demonstrated.

  1. On the Direct Electron Transfer, Sensing, and Enzyme Activity in the Glucose Oxidase/Carbon Nanotubes System

    OpenAIRE

    2013-01-01

    The signal transduction and enzyme activity were investigated in biosensors based on the glucose oxidase (GOx) and carbon nanotubes (CNT) embedded in a bio-adhesive film of chitosan (CHIT). The voltammetric studies showed that, regardless of CHIT matrix, the GOx adsorbed on CNT yielding a pair of surface-confined current peaks at -0.48 V. The anodic peak did not increase in the presence of glucose in an O2-free solution indicating the lack of direct electron transfer (DET) between the enzymat...

  2. Behavioral effects of α,α,β,β-tetradeutero-5-MeO-DMT in rats: comparison with 5-MeO-DMT administered in combination with a monoamine oxidase inhibitor

    Science.gov (United States)

    Halberstadt, Adam L.; Nichols, David E.; Geyer, Mark A.

    2012-01-01

    RATIONALE Ayahuasca is a psychoactive tea prepared from a combination of plants that contain a hallucinogenic tryptamine and monoamine oxidase inhibitors (MAOIs). Behavioral Pattern Monitor (BPM) experiments demonstrated that the combination of 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and a behaviorally inactive dose of an MAOA inhibitor such as harmaline or clorgyline induces biphasic effects on locomotor activity in rats, initially reducing locomotion and then increasing activity as time progresses. OBJECTIVES The present study investigated whether the biphasic locomotor profile induced by the combination of 5-MeO-DMT and an MAOI is a consequence of a reduction in the rate of 5-MeO-DMT metabolism. This hypothesis was tested using a deuterated derivative of 5-MeO-DMT (α,α,β,β-tetradeutero-5-MeO-DMT) that is resistant to metabolism by MAO. RESULTS Confirming our previous findings, 1.0 mg/kg 5-MeO-DMT (s.c.) had biphasic effects on locomotor activity in rats pretreated with a behaviorally inactive dose of the nonselective MAOI pargyline (10 mg/kg). Administration of 5-MeO-DMT alone, even at doses greater than 1.0 mg/kg, produced only reductions in locomotor activity. Although low doses of α,α,β,β-tetradeutero-5-MeO-DMT (0.3 and 1.0 mg/kg, s.c.) produced only hypoactivity in the BPM, a dose of 3.0 mg/kg induced a biphasic locomotor profile similar to that produced by the combination of 5-MeO-DMT and an MAOI. Receptor binding studies demonstrated that deuterium substitution had little effect on the affinity of 5-MeO-DMT for a wide variety of neurotransmitter binding sites. CONCLUSIONS The finding with α,α,β,β-tetradeutero-5-MeO-DMT indicates that the hyperactivity induced by 5-MeO-DMT after MAO inhibition is a consequence of reduced metabolism of 5-MeO-DMT, leading to prolonged occupation of central serotonin receptors. These results demonstrate that deuterated tryptamines may be useful in behavioral and pharmacological studies to mimic the effects of

  3. Effect of Monoamine Oxidase Inhibitor on the Differentiation of Malignant Glioma Cell%单胺氧化酶抑制剂诱导胶质瘤细胞的体外分化

    Institute of Scientific and Technical Information of China (English)

    邵根宝; 薄丹丹; 韩晓娟; 贺清华; 张严; 桑建荣

    2012-01-01

    To investigate the effect of monoamine oxidase inhibitor tranylcypromine (TCP) on the differentiation of human U251 glioma cells, we treated U251 cells with TCP and/or 100 nmol/L histone deacetylase inhibitor trychos-tatin A (TSA). The differentiation of U251 cells was observed with inverted microscopy. The cell proliferation and cell cycle distribution were determined by MTT assay and flow cytometry. respectively. Apoptosis was observed by Hoechst 33258 staining. The levels of differentiation-related genes were assessed by real-time PCR and Western blotting. TCP-induced differentiation was characterized by typical morphological changes, inhibition of cellular proliferation, accumulation of cells in the Gl phase of the cell cycle, decreased expression of the pluripotency transcription factors Oct4 and Sox2, and increased expression of glial fibrillary acid protein (GFAP). The combination of TCP and TSA treatment also triggered an over-expression of GFAP. These findings suggest that TCP may induce differentiation of U251 glioma cells, and the differentiation process may be promoted by histone deacetylase inhibitor TSA,%为研究单胺氧化酶抑制剂(TCP)对体外培养的入脑胶质瘤U251细胞的诱导分化作用,以不同浓度TCP单独或与100 nmol/L组蛋白去乙酰化酶抑制剂(TSA)联合处理U251细胞,采用倒置显微镜观察细胞形态学变化;噻唑蓝( MTT)比色法检测细胞增殖变化;流式细胞仪检测细胞周期变化;Hoechst 33258染色显示细胞凋亡;Real-time PCR和Western印迹法检测分化相关基因mRNA和蛋白表达水平的改变.结果表明:TCP可诱导细胞突起增多且变细长,抑制细胞增殖,阻滞细胞周期于G1期,抑制全能性转录因子Oct4和Sox2的表达,上调分化标志基因胶质纤维酸性蛋白(GFAP)的表达,TCP联合TSA也诱导了GFAP的高表达.这些结果提示:TCP可诱导胶质瘤U251细胞分化,TSA对TCP诱导细胞分化有协同作用.

  4. Immunocytochemical localization of monoamine oxidase type B in rat’s peripheral nervous system%单胺氧化酶B在大鼠外周神经系统中的定位

    Institute of Scientific and Technical Information of China (English)

    陈强; 徐洋

    2015-01-01

    Objective To investigate the expression of monoamine oxidase type B (MAOB)in rat’s peripheral nerv-ous system to provide morphologic basis for further study about MAOB and the relationship between axon transporta-tion and nerve impulse transduction.Methods The present study used immunohistochemical method to observe the lo-calization of MAOB in rat’s peripheral nervous system.Results Light microscopy reveals that MAOB immunoreactivi-ty is presented in epithelium above the lamina propria and lamina propria of rat’s tongue.Electron microscopy reveals that MAOB immunoreactivity is found in the myelinated axons and unmyelinated axons.MAOB immunoreactivity is al-so observed in the Schwann cell.In these MAO-B-positive structures,MAOB immunohistochemical reaction products are found on and around the mitochondrial outer membrane.Conclusion The abundeant MAOB in rat’s peripheral nervous system indicates that MAO-B plays a critical role in axon transportation and nerve impulse transduction.%目的:研究单胺氧化酶 B(MAOB)在大鼠外周神经系统中的表达,为进一步研究 MAOB 与外周神经系统中轴突运输和神经传导的关系提供形态学依据。方法采用免疫组织化学的方法,通过光镜和电镜观察 MAOB 在大鼠外周神经系统中的分布。结果光镜下,MAOB 免疫反应阳性细胞分布在舌体的上皮及固有层中。电镜下, MAOB 免疫反应阳性细胞分布在大鼠舌体有髓鞘和无髓鞘轴突中。阳性物质分布于细胞质中,准确来说为线粒体外膜上。结论 MAOB 在大鼠外周神经系统轴突的表达,提示 MAOB 可能与轴突的运输和神经传导有着非常重要的作用。

  5. Combined cross-linked enzyme aggregates of horseradish peroxidase and glucose oxidase for catalyzing cascade chemical reactions.

    Science.gov (United States)

    Nguyen, Le Truc; Yang, Kun-Lin

    2017-05-01

    Cascade reactions involved unstable intermediates are often encountered in biological systems. In this study, we developed combined cross-linked enzyme aggregates (combi-CLEA) to catalyze a cascade reaction which involves unstable hydrogen peroxide as an intermediate. The combi-CLEA contains two enzymes̶ glucose oxidase (GOx) and horseradish peroxidase (HRP) which are cross-linked together as solid aggregates. The first enzyme GOx catalyzes the oxidation of glucose and produces hydrogen peroxide, which is used by the second enzyme HRP to oxidize 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The apparent reaction rate of the cascade reaction reaches 10.5±0.5μM/min when the enzyme ratio is 150:1 (GOx:HRP). Interestingly, even in the presence of catalase, an enzyme that quickly decomposes hydrogen peroxide, the reaction rate only decreases by 18.7% to 8.3±0.3μM/min. This result suggests that the intermediate hydrogen peroxide is not decomposed by catalase due to a short diffusion distance between GOx and HRP in the combi-CLEA. Scanning electron microscopy images suggest that combi-CLEA particles are hollow spheres and have an average diameter around 250nm. Because of their size, combi-CLEA particles can be entrapped inside a nylon membrane for detecting glucose by using the cascade reaction.

  6. Bilirubin oxidase-like proteins from Podospora anserina: promising thermostable enzymes for application in transformation of plant biomass.

    Science.gov (United States)

    Xie, Ning; Ruprich-Robert, Gwenaël; Silar, Philippe; Chapeland-Leclerc, Florence

    2015-03-01

    Plant biomass degradation by fungi is a critical step for production of biofuels, and laccases are common ligninolytic enzymes envisioned for ligninolysis. Bilirubin oxidases (BODs)-like are related to laccases, but their roles during lignocellulose degradation have not yet been fully investigated. The two BODs of the ascomycete fungus Podospora anserina were characterized by targeted gene deletions. Enzymatic assay revealed that the bod1(Δ) and bod2(Δ) mutants lost partly a thermostable laccase activity. A triple mutant inactivated for bod1, bod2 and mco, a previously investigated multicopper oxidase gene distantly related to laccases, had no thermostable laccase activity. The pattern of fruiting body production in the bod1(Δ) bod2(Δ) double mutant was changed. The bod1(Δ) and bod2(Δ) mutants were reduced in their ability to grow on ligneous and cellulosic materials. Furthermore, bod1(Δ) and bod2(Δ) mutants were defective towards resistance to phenolic substrates and H2 O2 , which may also impact lignocellulose breakdown. Double and triple mutants were more affected than single mutants, evidencing redundancy of function among BODs and mco. Overall, the data show that bod1, bod2 and mco code for non-canonical thermostable laccases that participate in the degradation of lignocellulose. Thanks to their thermal stability, these enzymes may be more promising candidate for biotechnological application than canonical laccases.

  7. The Use of Cytochrome C Oxidase Enzyme Activity and Immunohistochemistry in Defining Mitochondrial Injury in Kidney Disease.

    Science.gov (United States)

    Zsengellér, Zsuzsanna K; Rosen, Seymour

    2016-09-01

    The renal biopsy is a dynamic way of looking at renal disease, and tubular elements are an important part of this analysis. The mitochondria in 20 renal biopsies were examined by immunohistochemical (electron transport chain enzyme: cytochrome C oxidase IV [COX IV]) and enzyme histochemical methods (COX), both by light and electron microscopy. The distal convoluted tubules and thick ascending limbs showed the greatest intensity in the COX immunostains and enzyme activity in controls. The degree of mitochondrial COX protein and enzyme activity diminished as the tubules became atrophic. With proximal hypertrophic changes, there was great variation in both COX activity and protein expression. In contrast, in three cases of systemic lupus erythematosus, biopsied for high-grade proteinuria, the activity was consistently upregulated, whereas protein expression remained normal. These unexpected findings of heterogeneous upregulation in hypertrophy and the dyssynchrony of protein expression and activity may indicate mitochondrial dysregulation. Functional electron microscopy showed COX activity delineated by the intense mitochondrial staining in normal or hypertrophic proximal tubules. With atrophic changes, residual small mitochondria with diminished activity could be seen. With mitochondrial size abnormalities (enlargement and irregularity, adefovir toxicity), activity persisted. In the renal biopsy, mitochondrial analysis is feasible utilizing immunohistochemical and enzyme histochemical techniques.

  8. New biotechnological perspectives of a NADH oxidase variant from Thermus thermophilus HB27 as NAD+-recycling enzyme

    Directory of Open Access Journals (Sweden)

    Rocha-Martín Javier

    2011-11-01

    Full Text Available Abstract Background The number of biotransformations that use nicotinamide recycling systems is exponentially growing. For this reason one of the current challenges in biocatalysis is to develop and optimize more simple and efficient cofactor recycling systems. One promising approach to regenerate NAD+ pools is the use of NADH-oxidases that reduce oxygen to hydrogen peroxide while oxidizing NADH to NAD+. This class of enzymes may be applied to asymmetric reduction of prochiral substrates in order to obtain enantiopure compounds. Results The NADH-oxidase (NOX presented here is a flavoenzyme which needs exogenous FAD or FMN to reach its maximum velocity. Interestingly, this enzyme is 6-fold hyperactivated by incubation at high temperatures (80°C under limiting concentrations of flavin cofactor, a change that remains stable even at low temperatures (37°C. The hyperactivated form presented a high specific activity (37.5 U/mg at low temperatures despite isolation from a thermophile source. Immobilization of NOX onto agarose activated with glyoxyl groups yielded the most stable enzyme preparation (6-fold more stable than the hyperactivated soluble enzyme. The immobilized derivative was able to be reactivated under physiological conditions after inactivation by high solvent concentrations. The inactivation/reactivation cycle could be repeated at least three times, recovering full NOX activity in all cases after the reactivation step. This immobilized catalyst is presented as a recycling partner for a thermophile alcohol dehydrogenase in order to perform the kinetic resolution secondary alcohols. Conclusion We have designed, developed and characterized a heterogeneous and robust biocatalyst which has been used as recycling partner in the kinetic resolution of rac-1-phenylethanol. The high stability along with its capability to be reactivated makes this biocatalyst highly re-useable for cofactor recycling in redox biotransformations.

  9. Nuclear expression of lysyl oxidase enzyme is an independent prognostic factor in rectal cancer patients

    DEFF Research Database (Denmark)

    Liu, Na; Cox, Thomas R; Cui, Weiyingqi;

    2016-01-01

    Emerging evidence has implicated a pivotal role for lysyl oxidase (LOX) in cancer progression and metastasis. Whilst the majority of work has focused on the extracellular matrix cross-linking role of LOX, the exact function of intracellular LOX localisation remains unclear. In this study, we anal...... the nucleus of colon cancer cell lines by confocal microscopy and Western blot. Our results show a powerful link between nuclear LOX expression in tumours and patient survival, and offer a promising prognostic biomarker for rectal cancer patients....

  10. Antidepressant-like effects of the xanthine oxidase enzyme inhibitor allopurinol in rats. A comparison with fluoxetine.

    Science.gov (United States)

    Gürbüz Özgür, Börte; Aksu, Hatice; Birincioğlu, Mustafa; Dost, Turhan

    2015-11-01

    Allopurinol is a xanthine oxidase enzyme inhibitor that is widely used for the treatment of hyperuricemia and gout. The activity of tryptophan 2,3-dioxygenase, which metabolizes tryptophan (TRP), is decreased by xanthine oxidase inhibitors, causing TRP levels in the body to be increased. Increases in TRP levels in the brain might have antidepressant effects. The purpose of this study is to evaluate the antidepressant effects of allopurinol compared to those of fluoxetine, which is a proven antidepressant. Thirty-two Wistar albino male rats were divided into four groups (control, 10mg/kg fluoxetine, 50mg/kg allopurinol, 50mg/kg allopurinol+10 mg/kg fluoxetine; n=8 per group), and forced swimming tests were performed before and after 14days of drug administration. Serotonin, 5-hydroxyindolacetic acid and uric acid levels were measured in blood samples after the final treatment. When allopurinol and fluoxetine were administered separately, a decrease in the duration of immobility and an increased duration of swimming were observed in the forced swimming test. The results showed similar antidepressant efficacies between allopurinol and fluoxetine. However, we found no statistically significant difference in the antidepressant effect of the combined therapy versus single drug therapy.

  11. MOLECULAR MODELLING OF HUMAN ALDEHYDE OXIDASE AND IDENTIFICATION OF THE KEY INTERACTIONS IN THE ENZYME-SUBSTRATE COMPLEX

    Directory of Open Access Journals (Sweden)

    Siavoush Dastmalchi

    2005-05-01

    Full Text Available Aldehyde oxidase (EC 1.2.3.1, a cytosolic enzyme containing FAD, molybdenum and iron-sulphur cluster, is a member of non-cytochrome P-450 enzymes called molybdenum hydroxylases which is involved in the metabolism of a wide range of endogenous compounds and many drug substances. Drug metabolism is one of the important characteristics which influences many aspects of a therapeutic agent such as routes of administration, drug interaction and toxicity and therefore, characterisation of the key interactions between enzymes and substrates is very important from drug development point of view. The aim of this study was to generate a three-dimensional model of human aldehyde oxidase (AO in order to assist us to identify the mode of interaction between enzyme and a set of phethalazine/quinazoline derivatives. Both sequence-based (BLAST and inverse protein fold recognition methods (THREADER were used to identify the crystal structure of bovine xanthine dehydrogenase (pdb code of 1FO4 as the suitable template for comparative modelling of human AO. Model structure was generated by aligning and then threading the sequence of human AO onto the template structure, incorporating the associated cofactors, and molecular dynamics simulations and energy minimization using GROMACS program. Different criteria which were measured by the PROCHECK, QPACK, VERIFY-3D were indicative of a proper fold for the predicted structural model of human AO. For example, 97.9 percentages of phi and psi angles were in the favoured and most favoured regions in the ramachandran plot, and all residues in the model are assigned environmentally positive compatibility scores. Further evaluation on the model quality was performed by investigation of AO-mediated oxidation of a set of phthalazine/quinazoline derivatives to develop QSAR model capable of describing the extent of the oxidation. Substrates were aligned by docking onto the active site of the enzyme using GOLD technology and then

  12. Amperometric enzyme electrodes for aerobic and anaerobic glucose monitoring prepared by glucose oxidase immobilized in mixed ferrocene-cobaltocenium dendrimers.

    Science.gov (United States)

    Alonso, Beatriz; Armada, Pilar García; Losada, José; Cuadrado, Isabel; González, Blanca; Casado, Carmen M

    2004-07-15

    The enzyme glucose oxidase (GOx) has been immobilized electrostatically onto carbon and platinum electrodes modified with mixed ferrocene-cobaltocenium dendrimers. The ferrocene units have been used successfully as mediators between the GOx and the electrode under anaerobic conditions. In experiments carried out in the presence of oxygen, the cobaltocenium moieties act as electrocatalysts in the reduction of the oxygen in the solution, thus making possible the determination of the oxygen variation due to the enzymatic reaction, with high sensitivity. The current response of the electrode was determined by measuring steady-state current values obtained applying a constant potential. The effect of the substrate concentration, the dendrimer generation, the thickness of the dendrimer layer, interferences, and storage on the response of the sensors were investigated.

  13. Cloning and expression of zebrafish genes encoding the heme synthesis enzymes uroporphyrinogen III synthase (UROS) and protoporphyrinogen oxidase (PPO).

    Science.gov (United States)

    Hanaoka, Ryuki; Dawid, Igor B; Kawahara, Atsuo

    2007-02-01

    Heme is synthesized from glycine and succinyl CoA by eight heme synthesis enzymes. Although genetic defects in any of these enzymes are known to cause severe human blood diseases, their developmental expression in mammals is unknown. In this paper, we report two zebrafish heme synthesis enzymes, uroporphyrinogen III synthase (UROS) and protoporphyrinogen oxidase (PPO) that are well conserved in comparison to their human counterparts. Both UROS and PPO formed pairs of bilateral stripes in the lateral plate mesoderm at the 15-somite stage. At 24 h post-fertilization (hpf), UROS and PPO were predominantly expressed in the intermediate cell mass (ICM) that is the major site of primitive hematopoiesis. The expression of UROS and PPO was drastically suppressed in the bloodless mutants cloche and vlad tepes/gata 1 from 15-somite to 24hpf stages, indicating that both cloche and vlad tepes/gata 1 are required for the induction and maintenance of UROS and PPO expression in the ICM.

  14. Characterization of Biosensors Based on Recombinant Glutamate Oxidase: Comparison of Crosslinking Agents in Terms of Enzyme Loading and Efficiency Parameters.

    Science.gov (United States)

    Ford, Rochelle; Quinn, Susan J; O'Neill, Robert D

    2016-01-01

    Amperometric l-glutamate (Glu) biosensors, based on both wild-type and a recombinant form of l-glutamate oxidase (GluOx), were designed and characterized in terms of enzyme-kinetic, sensitivity and stability parameters in attempts to fabricate a real-time Glu monitoring device suitable for future long-term detection of this amino acid in biological and other complex media. A comparison of the enzyme from these two sources showed that they were similar in terms of biosensor performance. Optimization of the loading of the polycationic stabilization agent, polyethyleneimine (PEI), was established before investigating a range of crosslinking agents under different conditions: glutaraldehyde (GA), polyethylene glycol (PEG), and polyethylene glycol diglycidyl ether (PEGDE). Whereas PEI-free biosensor designs lost most of their meager Glu sensitivity after one or two days, configurations with a 2:5 ratio of dip-evaporation applications of PEI(1%):GluOx(400 U/mL) displayed a 20-fold increase in their initial sensitivity, and a decay half-life extended to 10 days. All the crosslinkers studied had no effect on initial Glu sensitivity, but enhanced biosensor stability, provided the crosslinking procedure was carried out under well-defined conditions. The resulting biosensor design based on the recombinant enzyme deposited on a permselective layer of poly-(ortho-phenylenediamine), PoPD/PEI₂/GluOx₅/PEGDE, displayed good sensitivity (LOD term monitoring of Glu concentration dynamics in complex media.

  15. Heterodimeric l-amino acid oxidase enzymes from Egyptian Cerastes cerastes venom: Purification, biochemical characterization and partial amino acid sequencing

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    A.E. El Hakim

    2015-12-01

    Full Text Available Two l-amino acid oxidase enzyme isoforms, Cc-LAAOI and Cc-LAAOII were purified to apparent homogeneity from Cerastes cerastes venom in a sequential two-step chromatographic protocol including; gel filtration and anion exchange chromatography. The native molecular weights of the isoforms were 115 kDa as determined by gel filtration on calibrated Sephacryl S-200 column, while the monomeric molecular weights of the enzymes were, 60, 56 kDa and 60, 53 kDa for LAAOI and LAAOII, respectively. The tryptic peptides of the two isoforms share high sequence homology with other snake venom l-amino acid oxidases. The optimal pH and temperature values of Cc-LAAOI and Cc-LAAOII were 7.8, 50 °C and 7, 60 °C, respectively. The two isoenzymes were thermally stable up to 70 °C. The Km and Vmax values were 0.67 mM, 0.135 μmol/min for LAAOI and 0.82 mM, 0.087 μmol/min for LAAOII. Both isoenzymes displayed high catalytic preference to long-chain, hydrophobic and aromatic amino acids. The Mn2+ ion markedly increased the LAAO activity for both purified isoforms, while Na+, K+, Ca2+, Mg2+ and Ba2+ ions showed a non-significant increase in the enzymatic activity of both isoforms. Furthermore, Zn2+, Ni2+, Co2+, Cu2+ and AL3+ ions markedly inhibited the LAAOI and LAAOII activities. l-Cysteine and reduced glutathione completely inhibited the LAAO activity of both isoenzymes, whereas, β-mercaptoethanol, O-phenanthroline and PMSF completely inhibited the enzymatic activity of LAAOII. Furthermore, iodoacitic acid inhibited the enzymatic activity of LAAOII by 46% and had no effect on the LAAOI activity.

  16. Enzyme-Mediated Conversion of Flavin Adenine Dinucleotide (FAD) to 8-Formyl FAD in Formate Oxidase Results in a Modified Cofactor with Enhanced Catalytic Properties.

    Science.gov (United States)

    Robbins, John M; Souffrant, Michael G; Hamelberg, Donald; Gadda, Giovanni; Bommarius, Andreas S

    2017-07-25

    Flavins, including flavin adenine dinucleotide (FAD), are fundamental catalytic cofactors that are responsible for the redox functionality of a diverse set of proteins. Alternatively, modified flavin analogues are rarely found in nature as their incorporation typically results in inactivation of flavoproteins, thus leading to the disruption of important cellular pathways. Here, we report that the fungal flavoenzyme formate oxidase (FOX) catalyzes the slow conversion of noncovalently bound FAD to 8-formyl FAD and that this conversion results in a nearly 10-fold increase in formate oxidase activity. Although the presence of an enzyme-bound 8-formyl FMN has been reported previously as a result of site-directed mutagenesis studies of lactate oxidase, FOX is the first reported case of 8-formyl FAD in a wild-type enzyme. Therefore, the formation of the 8-formyl FAD cofactor in formate oxidase was investigated using steady-state kinetics, site-directed mutagenesis, ultraviolet-visible, circular dichroism, and fluorescence spectroscopy, liquid chromatography with mass spectrometry, and computational analysis. Surprisingly, the results from these studies indicate not only that 8-formyl FAD forms spontaneously and results in the active form of FOX but also that its autocatalytic formation is dependent on a nearby arginine residue, R87. Thus, this work describes a new enzyme cofactor and provides insight into the little-understood mechanism of enzyme-mediated 8α-flavin modifications.

  17. Female mice lacking active nadph-oxidase enzymes are protected against “western diet”--induced obesity and metabolic syndrome

    Science.gov (United States)

    NADPH oxidase (Nox) enzymes have been implicated in regulation of adipocyte differentiation and inflammation in a variety of tissues. We examined the effects of feeding AIN-93G or a “Western diet” (WD) (45% fat, 0.5% cholesterol) on development of obesity and “metabolic syndrome” in wild type (WT) m...

  18. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis.

    Science.gov (United States)

    Kopacz, Malgorzata M; Heuts, Dominic P H M; Fraaije, Marco W

    2014-10-01

    Putrescine oxidase from Rhodococcus erythropolis (PuO) is a flavin-containing amine oxidase from the monoamine oxidase family that performs oxidative deamination of aliphatic diamines. In this study we report pre-steady-state kinetic analyses of the enzyme with the use of single- and double-mixing stopped-flow spectroscopy and putrescine as a substrate. During the fast and irreversible reductive half-reaction no radical intermediates were observed, suggesting a direct hydride transfer from the substrate to the FAD. The rate constant of flavin reoxidation depends on the ligand binding; when the imine product was bound to the enzyme the rate constant was higher than with free enzyme species. Similar results were obtained with product-mimicking ligands and this indicates that a ternary complex is formed during catalysis. The obtained kinetic data were used together with steady-state rate equations derived for ping-pong, ordered sequential and bifurcated mechanisms to explore which mechanism is operative. The integrated analysis revealed that PuO employs a bifurcated mechanism due to comparable rate constants of product release from the reduced enzyme and reoxidation of the reduced enzyme-product complex.

  19. Estimation of Anadara tuberculosa genetic diversity in five mangroves from Tumaco, using Cytochrome oxidase I enzyme

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    Esmeralda Chamorro L

    2016-09-01

    Full Text Available Objective. To estimate the genetic diversity of the Anadara tuberculosa en five mangrove swams of Tumaco, Nariño, Colombia using as a mitocondrial molecular marker the cytochromo oxidase sub-unit I (COI. Materials and methods. A total of 50 individuals were collected from the San Jorge, La Tiburonera, El Pajal, La Playa y Bajito Vaquería mangrove swamps, randomly selecting 10 specimens of each zone. The tissue sample was worked with absolute alcohol at ambient temperature in microtubes. DNA was extracted, and the mitocondrial DNA was amplified using the PCR technique (polymerase chain reaction. The amplified and quantified products of PCR were sequenced on both sides (Macrogen. Each one of the obtained sequences was edited and aligned. Later, the parameters of genetic diversity (haplotypical and nucleotidical were measured, and the analysis of distribution between frequency pairs (Mistmach distribution was elaborated. Finally, the analysis of nucleotidic variation and population structure (AMOVA was completed. Results. The amplified product gene weighed 710 bp. The haplotypical diversity reported for all the populations was high (0.683±0.060 and the reported nucleotídical diversity was low for all the populations (0.040±0.020. The AMOVA results indicate that the variance amongst populations is low (4.20% and that the variance within populations is high (95.80%. Conclusions. The studied populations are not structured and although there is a decrease of natural banks, the genetic diversity is high.

  20. An aryl-alcohol oxidase of Pleurotus sapidus: heterologous expression, characterization, and application in a 2-enzyme system.

    Science.gov (United States)

    Galperin, Ilya; Javeed, Aysha; Luig, Hanno; Lochnit, Günter; Rühl, Martin

    2016-09-01

    Aryl-alcohol oxidases (AAOs) are enzymes supporting the degradation of lignin by fungal derived class II peroxidases produced by white-rot fungi. AAOs are able to generate H2O2 as a by-product via oxidation of an aryl-alcohol into its correspondent aldehyde. In this study, an AAO was heterologously expressed in a basidiomycete host for the first time. The gene for an AAO of the white-rot fungus Pleurotus sapidus, a close relative to the oyster mushroom Pleurotus ostreatus, was cloned into an expression vector and put under control of the promotor of the glyceraldehyde-3-phosphate dehydrogenase gene 2 (gpdII) of the button mushroom Agaricus bisporus. The expression vector was transformed into the model basidiomycete Coprinopsis cinerea, and several positive transformants were obtained. The best producing transformants were grown in shake-flasks and in a stirred tank reactor reaching enzymatic activities of up to 125 U L(-1) using veratryl alcohol as a substrate. The purified AAO was biochemically characterized and compared to the previously described native and recombinant AAOs from other Pleurotus species. In addition, a two-enzyme system comprising a dye-decolorizing peroxidase (DyP) from Mycetinis scorodonius and the P. sapidus AAO was successfully employed to bleach the anthraquinone dye Reactive Blue 5.

  1. The Peroxidase-Glucose Oxidase Enzyme System in the Undergraduate Laboratory.

    Science.gov (United States)

    Woolridge, Elisa; And Others

    1986-01-01

    Offers a series of experiments which introduce students to the general principles of enzymology. The experiment demonstrates several basic enzyme properties and the chromatographic exercises provide an analysis of each enzymatic activity. Questions are also presented for extending discussion on the activities. (ML)

  2. Secretory production of an FAD cofactor-containing cytosolic enzyme (sorbitol-xylitol oxidase from Streptomyces coelicolor) using the twin-arginine translocation (Tat) pathway of Corynebacterium glutamicum.

    Science.gov (United States)

    Scheele, Sandra; Oertel, Dan; Bongaerts, Johannes; Evers, Stefan; Hellmuth, Hendrik; Maurer, Karl-Heinz; Bott, Michael; Freudl, Roland

    2013-03-01

    Carbohydrate oxidases are biotechnologically interesting enzymes that require a tightly or covalently bound cofactor for activity. Using the industrial workhorse Corynebacterium glutamicum as the expression host, successful secretion of a normally cytosolic FAD cofactor-containing sorbitol-xylitol oxidase from Streptomyces coelicolor was achieved by using the twin-arginine translocation (Tat) protein export machinery for protein translocation across the cytoplasmic membrane. Our results demonstrate for the first time that, also for cofactor-containing proteins, a secretory production strategy is a feasible and promising alternative to conventional intracellular expression strategies.

  3. Pathological changes in platelet histamine oxidases in atopic eczema

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    Reinhold Kiehl

    1993-01-01

    Full Text Available Increased plasma histamine levels were associated with significantly lowered diamine and type B monoamine oxidase activities in platelet-rich plasma of atopic eczema (AE patients. The diamine oxidase has almost normal cofactor levels (pyridoxal phosphate and Cu2+ but the cofactor levels for type B monoamine oxidase (flavin adenine dinucleotide and Fe2+ are lowered. The biogenic amines putrescine, cadaverine, spermidine, spermine, tyramine and serotonin in the sera, as well as dopamine and epinephrine in EDTA-plasma were found to be normal. It is unlikely, therefore, that these amines are responsible for the decreased activities of monoamine and diamine oxidase in these patients. The most likely causative factors for the inhibition of the diamine oxidase are nicotine, alcohol, food additives and other environmental chemicals, or perhaps a genetic defect of the diamine oxidase.

  4. Arsenite oxidase from Ralstonia sp. 22: characterization of the enzyme and its interaction with soluble cytochromes.

    Science.gov (United States)

    Lieutaud, Aurélie; van Lis, Robert; Duval, Simon; Capowiez, Line; Muller, Daniel; Lebrun, Régine; Lignon, Sabrina; Fardeau, Marie-Laure; Lett, Marie-Claire; Nitschke, Wolfgang; Schoepp-Cothenet, Barbara

    2010-07-02

    We characterized the aro arsenite oxidation system in the novel strain Ralstonia sp. 22, a beta-proteobacterium isolated from soil samples of the Salsigne mine in southern France. The inducible aro system consists of a heterodimeric membrane-associated enzyme reacting with a dedicated soluble cytochrome c(554). Our biochemical results suggest that the weak association of the enzyme to the membrane probably arises from a still unknown interaction partner. Analysis of the phylogeny of the aro gene cluster revealed that it results from a lateral gene transfer from a species closely related to Achromobacter sp. SY8. This constitutes the first clear cut case of such a transfer in the Aro phylogeny. The biochemical study of the enzyme demonstrates that it can accommodate in vitro various cytochromes, two of which, c(552) and c(554,) are from the parent species. Cytochrome c(552) belongs to the sox and not the aro system. Kinetic studies furthermore established that sulfite and sulfide, substrates of the sox system, are both inhibitors of Aro activity. These results reinforce the idea that sulfur and arsenic metabolism are linked.

  5. Neonatal hyperglycemia induces oxidative stress in the rat brain: the role of pentose phosphate pathway enzymes and NADPH oxidase.

    Science.gov (United States)

    Rosa, Andrea Pereira; Jacques, Carlos Eduardo Dias; de Souza, Laila Oliveira; Bitencourt, Fernanda; Mazzola, Priscila Nicolao; Coelho, Juliana Gonzales; Mescka, Caroline Paula; Dutra-Filho, Carlos Severo

    2015-05-01

    Recently, the consequences of diabetes on the central nervous system (CNS) have received great attention. However, the mechanisms by which hyperglycemia affects the central nervous system remain poorly understood. In addition, recent studies have shown that hyperglycemia induces oxidative damage in the adult rat brain. In this regard, no study has assessed oxidative stress as a possible mechanism that affects the brain normal function in neonatal hyperglycemic rats. Thus, the present study aimed to investigate whether neonatal hyperglycemia elicits oxidative stress in the brain of neonate rats subjected to a streptozotocin-induced neonatal hyperglycemia model (5-day-old rats). The activities of glucose-6-phosphate-dehydrogenase (G6PD), 6-phosphogluconate-dehydrogenase (6-PGD), NADPH oxidase (Nox), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), the production of superoxide anion, the thiobarbituric acid-reactive substances (TBA-RS), and the protein carbonyl content were measured. Neonatal hyperglycemic rats presented increased activities of G6PD, 6PGD, and Nox, which altogether may be responsible for the enhanced production of superoxide radical anion that was observed. The enhanced antioxidant enzyme activities (SOD, CAT, and GSHPx) that were observed in neonatal hyperglycemic rats, which may be caused by a rebound effect of oxidative stress, were not able to hinder the observed lipid peroxidation (TBA-RS) and protein damage in the brain. Consequently, these results suggest that oxidative stress could represent a mechanism that explains the harmful effects of neonatal hyperglycemia on the CNS.

  6. Novel roles for the polyphenol oxidase enzyme in secondary metabolism and the regulation of cell death in walnut.

    Science.gov (United States)

    Araji, Soha; Grammer, Theresa A; Gertzen, Ross; Anderson, Stephen D; Mikulic-Petkovsek, Maja; Veberic, Robert; Phu, My L; Solar, Anita; Leslie, Charles A; Dandekar, Abhaya M; Escobar, Matthew A

    2014-03-01

    The enzyme polyphenol oxidase (PPO) catalyzes the oxidation of phenolic compounds into highly reactive quinones. Polymerization of PPO-derived quinones causes the postharvest browning of cut or bruised fruit, but the native physiological functions of PPOs in undamaged, intact plant cells are not well understood. Walnut (Juglans regia) produces a rich array of phenolic compounds and possesses a single PPO enzyme, rendering it an ideal model to study PPO. We generated a series of PPO-silenced transgenic walnut lines that display less than 5% of wild-type PPO activity. Strikingly, the PPO-silenced plants developed spontaneous necrotic lesions on their leaves in the absence of pathogen challenge (i.e. a lesion mimic phenotype). To gain a clearer perspective on the potential functions of PPO and its possible connection to cell death, we compared the leaf transcriptomes and metabolomes of wild-type and PPO-silenced plants. Silencing of PPO caused major alterations in the metabolism of phenolic compounds and their derivatives (e.g. coumaric acid and catechin) and in the expression of phenylpropanoid pathway genes. Several observed metabolic changes point to a direct role for PPO in the metabolism of tyrosine and in the biosynthesis of the hydroxycoumarin esculetin in vivo. In addition, PPO-silenced plants displayed massive (9-fold) increases in the tyrosine-derived metabolite tyramine, whose exogenous application elicits cell death in walnut and several other plant species. Overall, these results suggest that PPO plays a novel and fundamental role in secondary metabolism and acts as an indirect regulator of cell death in walnut.

  7. Rapid deactivation of NADPH oxidase in neutrophils: continuous replacement by newly activated enzyme sustains the respiratory burst.

    Science.gov (United States)

    Akard, L P; English, D; Gabig, T G

    1988-07-01

    The cell-free system for activation of the neutrophil NADPH oxidase allowed us to examine activation of the oxidase in the absence of its NADPH-dependent turnover. The covalent sulfhydryl-modifying reagent N-ethylmaleimide completely inhibited the activation step (Ki = 40 mumol/L) in the cell-free system but had no effect on turnover of the preactivated particulate NADPH oxidase (up to 1 mmol/L). When N-ethylmaleimide was added to intact neutrophils during the period of maximal O2 generation in response to stimuli that activate the respiratory burst (phorbol myristate acetate, f-Met-Leu-Phe, opsonized zymosan, arachidonic acid), O2- generation ceased within seconds. Study of components of the cell-free activation system indicated that the cytosolic cofactor was irreversibly inhibited by N-ethylmaleimide whereas the N-ethylmaleimide-treated, membrane-associated oxidase could be activated by arachidonate and control cytosolic cofactor. Likewise, the cell-free system prepared from intact neutrophils that had been briefly exposed to N-ethylmaleimide and then washed reflected the effects of N-ethylmaleimide on the isolated cell-free components: cytosolic cofactor activity was absent, but the membrane oxidase remained fully activatable. Thus inhibition of oxidase activation by N-ethylamaleimide unmasked a rapid deactivation step that was operative in intact neutrophils but not in isolated particulate NADPH oxidase preparations. The demonstrated specificity of N-ethylmaleimide for oxidase activation and lack of effect on turnover of the NADPH oxidase suggested that sustained O2- generation by intact neutrophils was a result of continued replenishment of a small pool of active oxidase. The existence of an inactive pool of NADPH oxidase molecules in particulate preparations from stimulated neutrophils was supported more directly by activating these preparations again in the cell-free system.

  8. Age and Heat Stress Related Changes in Monoamine Contents and Cholinesterase Activity in Some Central Nervous System Regions of Albino Rat Newborns

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    M. Bahgat

    2007-01-01

    Full Text Available The normal monoamine [norepinephrine (NE, epinephrine (E, dopamine (DA and serotonin (5-HT] contents and cholinestrase (chE activity were significantly and gradually increased with age progress between postnatal days 7 and 21 in cerebrum, cerebellum, medulla oblongata and spinal cord of rat newborns. The daily exposure of the newborns to 401C for 2 h induced deteriorated effects and the withdrawal period of 7 days failed to return these altered variables to normal levels. On the other hand, the high temperature exerted its most potent decreased effect on monoamine contents at 21 days old. This decrease may be attributed to the elevated activity of monoamine oxidase and/or the decreased activity of the key enzymes responsible for monoamine synthesis. The chE activity exhibited different effects in the tested CNS regions as a result of high temperature exposure; the enzyme activity was decreased markedly at days 7, 14 and 21 in cerebellum and medulla oblongata and lowered only at days 7 and 14 in cerebrum and at day 14 in spinal cord. The subsequent withdrawal for 7 days beyond day 21 produced marked weakening of effect of high temperature exposure on monoamine contents in all examined CNS regions except NE and 5-HT contents in cerebellum and DA level in medulla oblongata. In spite of this attenuation, the values recorded in the withdrawal group were still significantly lower than the normal levels. On the other hand, the chE activity became more deleteriously affected at day 28 in the treated CNS regions except in the medulla oblongata where it was profoundly ameliorated after the withdrawal period.

  9. Patterns of renal dopamine release to regulate diuresis and natriuresis during volume expansion: Role of renal monoamine-oxidase Perfiles de secreción de dopamina renal en la expansión de volumen para regular diuresis y natriuresis: Rol de la monoaminoxidasa renal

    Directory of Open Access Journals (Sweden)

    Verónica de Luca Sarobe

    2010-02-01

    Full Text Available Diuretic and natriuretic effects of renal dopamine (DA are well established. However, in volume expansion the pattern of renal DA release into urine (U DA V and the role of enzymes involved in DA synthesis/degradation have not yet been defined. The objective was to determine the pattern of U DA V during volume expansion and to characterize the involvement of monoamine-oxidase (MAO and aromatic amino-acid decarboxylase (AADC in this response. In this study male Wistar rats were expanded with NaCl 0.9% at a rate of 5% BWt per hour. At the beginning of expansion three groups received a single drug injection as follows: C (vehicle, Control, IMAO (MAO inhibitor Pargyline, 20 mg/kg BWt, i.v. and BNZ (AADC inhibitor Benserazide, 25 mg/kg BWt, i.v.. Results revealed that in C rats U DA V (ng/30 min/100g BWt increased in the first 30 min expansion from 11.5 ± 1.20 to 21.8 ± 3.10 (p La dopamina (DA intrarrenal ejerce efectos diuréticos y natriuréticos. Sin embargo, en los estado de expansión de volumen aún no está bien definido el patrón de liberación de dopamina renal hacia la orina y si cumplen un rol las enzimas involucradas en la síntesis o degradación de la amina. El objetivo del presente trabajo fue determinar el patrón de excreción urinaria de DA (U DA V durante la expansión de volumen, caracterizando la participación de las enzimas monoaminooxidasa (MAO y decarboxilasa de aminoácidos aromáticos (AADC en esta respuesta. Para ello ratas Wistar macho fueron expandidas de volumen con NaCl 0.9% al 5% del peso corporal por hora durante dos horas y divididas en tres grupos, los que al comienzo de la expansión recibieron: C (vehículo, Control, IMAO (Pargilina, inhibidor de MAO, 20 mg/kg PC, i.v. y BNZ (Benserazida, inhibidor de AADC, 25 mg/kg PC, i.v.. Se observó que en C la U DA V (ng/30min/100gPC aumentó durante los primeros 30 minutos de expansión de 11.5 ± 1.20 a 21.8 ± 3.10 (p < 0.05, disminuyendo posteriormente. IMAO mostr

  10. [Concentration of monoamines and activity of several enzymes in the arcuate nucleus of the hypothalamus in young and aging rats during the estrous cycle].

    Science.gov (United States)

    Grantyn', V A

    1976-07-01

    The arcuate nucleus (AN) and the median eminence (ME) of the hypothalamus were investigated in young and ageing female rats. During the estral cycle (EC) the monoamine (MA) content, the monoaminoxidase (MAO), NADP and NAD-diaphorase activities were determined in the AN, and the MA content and the activity of alkaline phosphatase (AP) -- in the ME. In young rats in the proestrus-estrus there was an increase in the activity of the NADP and NAD-diaphorase and of the MA content, but a decrease of the MAO activity. This indicated an intensified function of the nucleus at these stages of the EC. Accumulation of the MA in the ME was noted in the diestrus, while in the proestrus their concentration sharply fell; on the other hand, the activity of the AP was considerably increased. In the ageing rats the dynamics of the indices under study during the EC were largely unchanged. However, the functional activity of the AN proved to increase, and in the ME and elevation of the MA concentration and disturbance of its release from the nerve terminals was seen.

  11. Polyamine oxidase 7 is a terminal catabolism-type enzyme in Oryza sativa and is specifically expressed in anthers.

    Science.gov (United States)

    Liu, Taibo; Kim, Dong Wook; Niitsu, Masaru; Maeda, Shunsuke; Watanabe, Masao; Kamio, Yoshiyuki; Berberich, Thomas; Kusano, Tomonobu

    2014-06-01

    Polyamine oxidase (PAO), which requires FAD as a cofactor, functions in polyamine catabolism. Plant PAOs are classified into two groups based on their reaction modes. The terminal catabolism (TC) reaction always produces 1,3-diaminopropane (DAP), H2O2, and the respective aldehydes, while the back-conversion (BC) reaction produces spermidine (Spd) from tetraamines, spermine (Spm) and thermospermine (T-Spm) and/or putrescine from Spd, along with 3-aminopropanal and H2O2. The Oryza sativa genome contains seven PAO-encoded genes termed OsPAO1-OsPAO7. To date, we have characterized four OsPAO genes. The products of these genes, i.e. OsPAO1, OsPAO3, OsPAO4 and OsPAO5, catalyze BC-type reactions. Whereas OsPAO1 remains in the cytoplasm, the other three PAOs localize to peroxisomes. Here, we examined OsPAO7 and its gene product. OsPAO7 shows high identity to maize ZmPAO1, the best characterized plant PAO having TC-type activity. OsPAO7 seems to remain in a peripheral layer of the plant cell with the aid of its predicted signal peptide and transmembrane domain. Recombinant OsPAO7 prefers Spm and Spd as substrates, and it produces DAP from both substrates in a time-dependent manner, indicating that OsPAO7 is the first TC-type enzyme identified in O. sativa. The results clearly show that two types of PAOs co-exist in O. sativa. Furthermore, OsPAO7 is specifically expressed in anthers, with an expressional peak at the bicellular pollen stage. The physiological function of OsPAO7 in anthers is discussed.

  12. Let the substrate flow, not the enzyme: Practical immobilization of d-amino acid oxidase in a glass microreactor for effective biocatalytic conversions.

    Science.gov (United States)

    Bolivar, Juan M; Tribulato, Marco A; Petrasek, Zdenek; Nidetzky, Bernd

    2016-11-01

    Exploiting enzymes for chemical synthesis in flow microreactors necessitates their reuse for multiple rounds of conversion. To achieve this goal, immobilizing the enzymes on microchannel walls is a promising approach, but practical methods for it are lacking. Using fusion to a silica-binding module to engineer enzyme adsorption to glass surfaces, we show convenient immobilization of d-amino acid oxidase on borosilicate microchannel plates. In confocal laser scanning microscopy, channel walls appeared uniformly coated with target protein. The immobilized enzyme activity was in the range expected for monolayer coverage of the plain surface with oxidase (2.37 × 10(-5)  nmol/mm(2) ). Surface attachment of the enzyme was completely stable under flow. The operational half-life of the immobilized oxidase (25°C, pH 8.0; soluble catalase added) was 40 h. Enzymatic oxidation of d-Met into α-keto-γ-(methylthio)butyric acid was characterized in single-pass and recycle reactor configurations, employing in-line measurement of dissolved O2 , and off-line determination of the keto-acid product. Reaction-diffusion time-scale analysis for different flow conditions showed that the heterogeneously catalyzed reaction was always slower than diffusion of O2 to the solid surface (DaII  ≤ 0.3). Potential of the microreactor for intensifying O2 -dependent biotransformations restricted by mass transfer in conventional reactors is thus revealed. Biotechnol. Bioeng. 2016;113: 2342-2349. © 2016 Wiley Periodicals, Inc.

  13. ADP competes with FAD binding in putrescine oxidase.

    Science.gov (United States)

    van Hellemond, Erik W; Mazon, Hortense; Heck, Albert J; van den Heuvel, Robert H H; Heuts, Dominic P H M; Janssen, Dick B; Fraaije, Marco W

    2008-10-17

    Putrescine oxidase from Rhodococcus erythropolis NCIMB 11540 (PuO(Rh)) is a soluble homodimeric flavoprotein of 100 kDa, which catalyzes the oxidative deamination of putrescine and some other aliphatic amines. The initial characterization of PuO(Rh) uncovered an intriguing feature: the enzyme appeared to contain only one noncovalently bound FAD cofactor per dimer. Here we show that this low FAD/protein ratio is the result of tight binding of ADP, thereby competing with FAD binding. MS analysis revealed that the enzyme is isolated as a mixture of dimers containing two molecules of FAD, two molecules ADP, or one FAD and one ADP molecule. In addition, based on a structural model of PuO(Rh) that was built using the crystal structure of human monoamine oxidase B (MAO-B), we constructed an active mutant enzyme, PuO(Rh) A394C, that contains covalently bound FAD. These findings show that the covalent FAD-protein linkage can be formed autocatalytically and hint to a new-found rationale for covalent flavinylation: covalent flavinylation may have evolved to prevent binding of ADP or related cellular compounds, which would prohibit formation of flavinylated and functional enzyme.

  14. Electron-paramagnetic-resonance studies of structure and function of the two-haem enzymes Pseudomonas cytochrome c peroxidase and beef heart cytochrome c oxidase.

    Science.gov (United States)

    Vänngård, T

    1985-06-01

    Beef heart cytochrome c oxidase contains two cytochromes, a and a3, and Pseudomonas aeruginosa cytochrome c peroxidase has one high- and one low-potential c haem, cHP and cLP. The parallelism in co-ordination and spin states between cytochrome a and haem cHP on the one hand and between cytochrome a3 and haem cLP on the other is illustrated. The two latter haems become accessible to cyanide, when the former are reduced. Such reduction also leads to an activation of the enzymes. Mechanisms are presented in which ferryl forms of cytochromes a3 and haem cLP take part. The enzymes reach an oxidation state, formally the same as resting enzyme, but with different properties.

  15. [Antimycoplasmic Activity of Fermentation Broth of Trichoderma harzianum Rifai F-180, an Organism Producing L-Lysine-α-Oxidase, an Antitumor and Antiviral Enzyme].

    Science.gov (United States)

    Smirnova, I P; Rakovskaya, I V

    2014-01-01

    A concentrate of the fermentation broth of Trichoderma harzianum Rifai F-180, an organism producing L-lysine-α-oxidase, an antitumor and antiviral enzyme, with the activity in the fermentation broth of 0.54-0.56 U/mI was recovered. The effect of the concentrate on the mycoplasmas growth was investigated for the first time. Two representatives of Mycoplasmafaceae, i.e. Mycoplasma hominis and Mycoplasma fermentans and one representative of Aholeplasmataceae. i. e. Aholeplasma laidlawii were used. It was shown that the fermentation broth inhibited the growth of Mycoplasma hominis after the preliminary exposure. The inhibition rate depended on the mycoplasma inoculation dose and the fermentation broth concentration.

  16. Formate oxidase, an enzyme of the glucose-methanol-choline oxidoreductase family, has a His-Arg pair and 8-formyl-FAD at the catalytic site.

    Science.gov (United States)

    Doubayashi, Daiju; Ootake, Takumi; Maeda, Yosifumi; Oki, Masaya; Tokunaga, Yuji; Sakurai, Akihiko; Nagaosa, Yukio; Mikami, Bunzo; Uchida, Hiroyuki

    2011-01-01

    Formate oxidase of Aspergillus oryzae RIB40 contains an 8-replaced FAD with molecular mass of 799 as cofactor. The ¹H-NMR spectrum of the cofactor fraction obtained from the enzyme indicated that the 8-replaced FAD in the fraction was 8-formyl-FAD, present in open form and hemiacetal form. The oxidation-reduction potentials of the open and hemiacetal forms were estimated by cyclic voltammetry to be -47 and -177 mV vs. Normal Hydrogen Electrode respectively. The structure of the enzyme was constructed using diffraction data to 2.24 Å resolution collected from a crystal of the enzyme. His₅₁₁ and Arg₅₅₄ were situated close to the pyrimidine part of the isoalloxazine ring of 8-formyl-FAD in open form. The enzyme had 8-formyl-FAD, the oxidation potential of which was approximately 160 mV more positive than that of FAD, and the His-Arg pair at the catalytic site, unlike the other enzymes belonging to the glucose-methanol-choline oxidoreductase family.

  17. 胆道恶性肿瘤中单胺氧化酶-A对肿瘤相关巨噬细胞抗肿瘤免疫功能的影响%Effect of monoamine oxidase-A on the anti-tumor immunity of tumor-associated macrophages in biliary tract cancers

    Institute of Scientific and Technical Information of China (English)

    赖佳明; 陈健聪; 陈伟; 张朝晖; 黄力; 梁力建

    2015-01-01

    Objective To investigate the effect of monoamine oxidase-A (MAO-A) in biliary tract cancers (BTCs) on the immunity of tumor-associated macrophages.Methods MAO-A expression plasmid and control plasmid were constructed and transiently transfected into BTC cell lines respectively.Macrophages were derived from peripheral blood mononuclear cells donated by healthy volunteers.Macrophages were then cocultured with aforementioned transfected cancer cell lines for 48 h respectively,Western blotting and enzyme linked immunosorbent assay (ELISA) were applied to assess the expression of immune effector proteins and the excretion of cytokines from cocultured macrophages.24 h priming of macrophages with human recombinant interferon-γ (IFN-γ) were performed after their first stage of coculture;then the second stage of coculture with corresponding transfected cancer cell lines for 48 h were followed.Flow cytometry was employed to detect necrosis and apotosis of cancer cells induced by cocultured macrophages.Results The expression of MAO-A was down-regulated in BTC cell lines,which polarized the cocultured macrophages into M2 type tumor-associated macrophages,and promoted their excretion of interleukin (IL)-10 and expression of PD-L1,while suppressed their excretion of tumor necrosis factor-α (TNF-α),IL-1β and IL-12p70 (18.8±2.3 vs.31.7±1.9,75.0±0.4 vs.150.2±17.0 and 49.1 ± 15.2 vs.135.2 ± 1.0,respectively,P < 0.05),as well as the expression of Human leukocyte antigen-DR (HLA-DR).On the contrary,however,macrophages cocultured with MAO-A overexpressing BTC cells exhibited pro-inflammatory phenotype (M1 type) which opposite to above suppressive immunity phenotype (M2 type).After priming of IFN-γ,macrophages cocultured with MAO-A overexpressing BTC cells induced tumor necrosis and apoptosis more effectively than those cocultured with control BTCcells [(84.85±5.66)% vs.(1.56±0.46)% and (76.73 ±6.31)% vs.(1.28±0.57)%,respectively,P < 0.05].Conclusion Down

  18. Study on the Correlation between Single Nucleotide Polymorphism of Monoamine Oxidase A Gene and Anger Regulation%单胺氧化酶A基因单核苷酸多态性与愤怒调节的关系研究

    Institute of Scientific and Technical Information of China (English)

    闫秀娟; 詹向红; 侯俊林; 刘永; 王淑玲; 李伟; 闫国立; 王友杰; 杨丽萍

    2012-01-01

    目的 研究单胺氧化酶A( monoamine oxidase A,MAOA)基因单核苷酸多态性(single nucleotide polymorphism,SNP)与怒的调节关系.方法 以某学院健康大学生为研究对象,根据状态-特质愤怒表达量表2(State-Trait Anger Expression Inventory-Ⅱ,STAXI-2)特质怒得分筛选受试者,其中高特质怒者225名,低特质怒者221名,经采血后,采用酚-氯仿法提取DNA,聚合酶链反应-连接酶检测反应(PCR-LDR)法对MAOA基因上的4个tag SNP位点(rs5906957、rs2235186、rs1181275和rs5905613)进行基因分型,对高、低特质怒不同性别组MAOA基因4个tag SNP位点不同基因型受试者怒的表达量表得分和怒的控制量表得分进行统计分析.结果 低特质怒女性MAOA基因rs2235186位点不同基因型组控制发怒得分比较,差异有统计学意义(P =0.037),其余3个tag SNP位点的不同基因型受试者在怒的表达及控制得分上比较,差异均无统计学意义(P>0.05).结论 MAOA基因tag SNP rs2235186多态性与我国健康大学生低特质怒女性的控制发怒特质有关.%Objective To study the correlation between single nucleotide polymorphism (SNP) of monoamine oxidase A gene (MAOA) and anger regulation. Methods Enrolled were healthy students from some college , including 225 of the high trait anger and 221 of the low trait anger. Subjects were recruited referring to the State-Trait Anger Expression Inventory 2 (STAXI-2) and their blood sampled. The DNA was extracted using phenol-chloroform method, 4 tag SNPs of MAOA (rs5906957, rs2235186, rs1181275, and rs5905613) were genotyped by PCR-based ligase detection reaction (PCR-LDR). The scores for trait anger expression inventory and the scores for trait anger expression control at the 4 tag SNPs of MAOA in the different sexes groups of the high and the low trait anger were statistical analyzed. Results There was statistical difference in anger control score of locus rs2235186 of MAOA gene group (P=0.037). There was no

  19. Simulating the slow to fast switch in cytochrome c oxidase catalysis by introducing a loop flip near to the enzyme's cytochrome c (substrate) binding site.

    Science.gov (United States)

    Alleyne, Trevor; Ignacio, Diane N; Sampson, Valerie B; Ashe, Damian; Wilson, Michael

    2016-08-04

    The mitochondrial enzyme cytochrome c oxidase catalyses the reduction of molecular oxygen in the critical step of oxidative phosphorylation that links the oxidation of food consumed to ATP production in cells. The enzyme catalyses the reduction of oxygen at two vastly different rates that are thought to be linked to two different conformations but the conformation of the 'fast enzyme' remains obscure. In this study we demonstrated how oxygen binding at haem a3 could trigger long distance conformational changes and then simulated a conformational change in an eight residue loop near to the enzyme's substrate (cytochrome c) binding site. We then used this modified COX to simulate a stable COX-cytochrome c ES-complex. Compared to ES-complexes formed in the absence of the conformation change, the distance between the redox centres of the two proteins was reduced by half and instead of nine, only four COX amino acid residues were found along the axis linking the electron entry point and the CuA redox centre of COX: We proposed that intramolecular electron transfer in COX occurs via a charge/hydrogen relay system involving these four residues. We suggest that the conformational change and resulting shortened electron pathway are features of fast-acting COX. This article is protected by copyright. All rights reserved.

  20. Optimization of bioselective membrane of amperometric enzyme sensor on basis of glucose oxidase using NH2-modified multi-wall carbone nanotubes

    Directory of Open Access Journals (Sweden)

    Korpan Ya. I.

    2010-02-01

    Full Text Available Aim. To investigate a possibility of application of multi-wall carbone nanotubes modified with NH2-groups (MWCNT-NH2 for creation of sensitive elements of the amperometric biosensor based on immobilized oxidoreductases, in particular, glucose oxidase (GOD. To study electrochemical properties of the membranes obtained. Methods. Experiments were carried out with amperometric methods using the ìStat 200 device («DropSens», Spain. The enzymes were immobilised in glutaraldehyde vapour. Results. The method of formation of bioselective matrix based on immobilised GOD with MNP-NH2 on the surface of gold amperometric electrodes was optimised. Optimal working conditions of the biosensor developed were determined. Conclusion. MWCNT integration into a bioselective matrix improves the biosensor analytical characteristics which means: higher signal value, wider linear range of glucose analysis, and possibility of substrate determination in wide range of working potential.

  1. Thiol-disulfide exchange between the PDI family of oxidoreductases negates the requirement for an oxidase or reductase for each enzyme.

    Science.gov (United States)

    Oka, Ojore B V; Yeoh, Hui Y; Bulleid, Neil J

    2015-07-15

    The formation of disulfides in proteins entering the secretory pathway is catalysed by the protein disulfide isomerase (PDI) family of enzymes. These enzymes catalyse the introduction, reduction and isomerization of disulfides. To function continuously they require an oxidase to reform the disulfide at their active site. To determine how each family member can be recycled to catalyse disulfide exchange, we have studied whether disulfides are transferred between individual PDI family members. We studied disulfide exchange either between purified proteins or by identifying mixed disulfide formation within cells grown in culture. We show that disulfide exchange occurs efficiently and reversibly between specific PDIs. These results have allowed us to define a hierarchy for members of the PDI family, in terms of ability to act as electron acceptors or donors during thiol-disulfide exchange reactions and indicate that there is no kinetic barrier to the exchange of disulfides between several PDI proteins. Such promiscuous disulfide exchange negates the necessity for each enzyme to be oxidized by Ero1 (ER oxidoreductin 1) or reduced by a reductive system. The lack of kinetic separation of the oxidative and reductive pathways in mammalian cells contrasts sharply with the equivalent systems for native disulfide formation within the bacterial periplasm.

  2. Immobilisation and characterisation of biocatalytic co-factor recycling enzymes, glucose dehydrogenase and NADH oxidase, on aldehyde functional ReSyn™ polymer microspheres.

    Science.gov (United States)

    Twala, Busisiwe V; Sewell, B Trevor; Jordaan, Justin

    2012-05-10

    The use of enzymes in industrial applications is limited by their instability, cost and difficulty in their recovery and re-use. Immobilisation is a technique which has been shown to alleviate these limitations in biocatalysis. Here we describe the immobilisation of two biocatalytically relevant co-factor recycling enzymes, glucose dehydrogenase (GDH) and NADH oxidase (NOD) on aldehyde functional ReSyn™ polymer microspheres with varying functional group densities. The successful immobilisation of the enzymes on this new high capacity microsphere technology resulted in the maintenance of activity of ∼40% for GDH and a maximum of 15.4% for NOD. The microsphere variant with highest functional group density of ∼3500 μmol g⁻¹ displayed the highest specific activity for the immobilisation of both enzymes at 33.22 U mg⁻¹ and 6.75 U mg⁻¹ for GDH and NOD with respective loading capacities of 51% (0.51 mg mg⁻¹) and 129% (1.29 mg mg⁻¹). The immobilised GDH further displayed improved activity in the acidic pH range. Both enzymes displayed improved pH and thermal stability with the most pronounced thermal stability for GDH displayed on ReSyn™ A during temperature incubation at 65 °C with a 13.59 fold increase, and NOD with a 2.25-fold improvement at 45 °C on the same microsphere variant. An important finding is the suitability of the microspheres for stabilisation of the multimeric protein GDH.

  3. [Catecholamines and their metabolic enzymes in the rat myocardium after a flight on the Kosmos-936 biosatellite].

    Science.gov (United States)

    Kwetncanski, R; Tigranian, R A; Torda, T

    1982-01-01

    In the myocardium of the weightless and centrifuged rats flown for 18.5 days onboard the biosatellite Cosmos-936 the catecholamine concentration and activity of enzymes involved in their synthesis and degradation--dopamine-beta-hydroxylase, monoamine oxidase and catechol-O-methyl transferase--were measured. The catecholamine concentration in the myocardium of both flight groups significantly increased, and the enzyme activity did not change. These results suggest that an exposure to space flight increases the catecholamine concentration and exerts no effect on their synthesis and degradation in the rat myocardium.

  4. Purification and characterization of polyphenol oxidase from nettle (Urtica dioica L.) and inhibitory effects of some chemicals on enzyme activity.

    Science.gov (United States)

    Güllçin, Ilhami; Küfrevioğlu, O Irfan; Oktay, Münir

    2005-06-01

    Polyphenol oxidase (PPO) of nettle (Urtica dioica L.) was extracted and purified through (NH4)2SO4 precipitation, dialysis, and CM-Sephadex ion-exchange chromatography and was used for its characterization. The PPO showed activity to catechol, 4-methylcatechol, L-3,4-dihydroxyphenylalanine (L-DOPA), L-tyrosine, p-cresol, pyrogallol, catechin and trans-cinnamic acid. For each of these eight substrates, optimum conditions such as pH and temperature were determined and L-tyrosine was found to be one of the most suitable substrates. Optimum pH and temperature were found at pH 4.5 and 30 degrees C respectively and Km and Vmax values were 7.90 x 10(-4) M, and 11290 EU/mL for with L-tyrosine as substrate. The inhibitory effect of several inhibitors, L-cysteine chloride, sodium azide, sodium cyanide, benzoic acid, salicylic acid, L-ascorbic acid, glutathione, thiourea, sodium diethyl dithiocarbamate, beta-mercaptoethanol and sodium metabisulfite were tested. The most effective was found to be sodium diethyl dithiocarbamate which acted as a competitive inhibitor with a Ki value of 1.79 x 10(-9)M. In addition one isoenzyme of PPO was detected by native polacrylamide slab gel electrophoresis.

  5. Fabrication of Mediatorless/Membraneless Glucose/Oxygen Based Biofuel Cell using Biocatalysts Including Glucose Oxidase and Laccase Enzymes

    Science.gov (United States)

    Christwardana, Marcelinus; Kim, Ki Jae; Kwon, Yongchai

    2016-07-01

    Mediatorless and membraneless enzymatic biofuel cells (EBCs) employing new catalytic structure are fabricated. Regarding anodic catalyst, structure consisting of glucose oxidase (GOx), poly(ethylenimine) (PEI) and carbon nanotube (CNT) is considered, while three cathodic catalysts consist of glutaraldehyde (GA), laccase (Lac), PEI and CNT that are stacked together in different ways. Catalytic activities of the catalysts for glucose oxidation and oxygen reduction reactions (GOR and ORR) are evaluated. As a result, it is confirmed that the catalysts work well for promotion of GOR and ORR. In EBC tests, performances of EBCs including 150 μm-thick membrane are measured as references, while those of membraneless EBCs are measured depending on parameters like glucose flow rate, glucose concentration, distance between two electrodes and electrolyte pH. With the measurements, how the parameters affect EBC performance and their optimal conditions are determined. Based on that, best maximum power density (MPD) of membraneless EBC is 102 ± 5.1 μW · cm‑2 with values of 0.5 cc · min‑1 (glucose flow rate), 40 mM (glucose concentration), 1 mm (distance between electrodes) and pH 3. When membrane and membraneless EBCs are compared, MPD of the membraneless EBC that is run at the similar operating condition to EBC including membrane is speculated as about 134 μW · cm‑2.

  6. Inhibition of biofilms by glucose oxidase, lactoperoxidase and guaiacol: the active antibacterial component in an enzyme alginogel.

    Science.gov (United States)

    Cooper, Rose A

    2013-12-01

    The association of biofilms with wound chronicity has prompted a search for antimicrobial interventions that are effective against biofilms. A patented preparation of glucose oxidase, lactoperoxidase and guaiacol (GLG), which is the antibacterial component of Flaminal, has been shown to inhibit a wide range of bacteria, but it has not yet been tested on biofilms. This study aims to determine the effect of GLG on biofilms of Staphylococcus aureus, methicillin-resistant S. aureus and Pseudomonas aeruginosa. Static biofilms were grown in microtitre plates and on coverslips and treated with a range of concentrations of GLG. Effects were monitored by estimating biofilm biomass by staining with crystal violet, biofilm activity by staining with either resazurin or fluorescein diacetate and biofilm viability by staining with LIVE/DEAD BacLight Bacterial Viability Kit. GLG was able to prevent the formation of biofilms at concentration ≤0.5% (w/v) and higher concentrations were required to inhibit established biofilms. GLG did not disrupt biofilm biomass. Staphylococci were more susceptible to GLG than P. aeruginosa. These in vitro findings must be verified by in vivo studies.

  7. Effects of Terpinen-4-ol on Four Metabolic Enzymes and Polyphenol Oxidase (PPO) in Mythimna separta Walker

    Institute of Scientific and Technical Information of China (English)

    MA Zhi-qing; HAN Xiu-ling; FENG Jun-tao; LI Guang-ze; ZHANG Xing

    2008-01-01

    To study insecticidal mechanism of terpinen-4-ol, a main insecticidal composition in the essential oil of Sabina vulgaris, the 5th instar larvae of Mythimna separta, were investigated with terpinen-4-ol by topical application. The activities of phosphatase, glutathione S-transferase (GSTs), cytochrome P450 (P450), and polyphenol oxidase (PPO) of tested insects were determined in all poisoning stages, including exciting stage, convulsing stage, paralysis stage, and recover stage. The result showed that the activities of both acid phosphatase (ACP) and alkaline phosphatase (AKP) in treated insects were induced by terpinen-4-ol, but ACP was inhibited in paralysis stage. The activities of GSTs were inhibited in exciting stage, convulsing stage, and paralysis stage, but gradually recovered in recover stage. O-demethylase activity of cytochrome P450 was inhibited by terpinen-4-ol, and the inhibition rate in all poisoning stages were 26.27, 46.03, 80.24, and 90.22%, respectively. PPO activities were strongly inhibited by terpinen-4-ol both in vitro and in vivo. In conclusion, the activities of P450, GSTs, and PPO could have relation with toxicity of terpinen-4-ol against larvae of the Mythimna separta, but recover stage of the poisoning insects might be related to GSTs induced. As a new insecticide or synergist, terpinen- 4-ol has a potential value in field of insecticide resistance management.

  8. A classification scheme for alternative oxidases reveals the taxonomic distribution and evolutionary history of the enzyme in angiosperms.

    Science.gov (United States)

    Costa, José Hélio; McDonald, Allison E; Arnholdt-Schmitt, Birgit; Fernandes de Melo, Dirce

    2014-11-01

    A classification scheme based on protein phylogenies and sequence harmony method was used to clarify the taxonomic distribution and evolutionary history of the alternative oxidase (AOX) in angiosperms. A large data set analyses showed that AOX1 and AOX2 subfamilies were distributed into 4 phylogenetic clades: AOX1a-c/1e, AOX1d, AOX2a-c and AOX2d. High diversity in AOX family compositions was found. While the AOX2 subfamily was not detected in monocots, the AOX1 subfamily has expanded (AOX1a-e) in the large majority of these plants. In addition, Poales AOX1b and 1d were orthologous to eudicots AOX1d and then renamed as AOX1d1 and 1d2. AOX1 or AOX2 losses were detected in some eudicot plants. Several AOX2 duplications (AOX2a-c) were identified in eudicot species, mainly in the asterids. The AOX2b originally identified in eudicots in the Fabales order (soybean, cowpea) was divergent from AOX2a-c showing some specific amino acids with AOX1d and then it was renamed as AOX2d. AOX1d and AOX2d seem to be stress-responsive, facultative and mutually exclusive among species suggesting a complementary role with an AOX1(a) in stress conditions. Based on the data collected, we present a model for the evolutionary history of AOX in angiosperms and highlight specific areas where further research would be most beneficial. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Characterization of the enzymatic and structural properties of human D-aspartate oxidase and comparison with those of the rat and mouse enzymes.

    Science.gov (United States)

    Katane, Masumi; Kawata, Tomonori; Nakayama, Kazuki; Saitoh, Yuki; Kaneko, Yuusuke; Matsuda, Satsuki; Saitoh, Yasuaki; Miyamoto, Tetsuya; Sekine, Masae; Homma, Hiroshi

    2015-01-01

    D-Aspartate (D-Asp), a free D-amino acid found in mammals, plays crucial roles in the neuroendocrine, endocrine, and central nervous systems. Recent studies have implicated D-Asp in the pathophysiology of infertility and N-methyl-D-Asp receptor-related diseases. D-Asp oxidase (DDO), a degradative enzyme that is stereospecific for acidic D-amino acids, is the sole catabolic enzyme acting on D-Asp in mammals. Human DDO is considered an attractive therapeutic target, and DDO inhibitors may be potential lead compounds for the development of new drugs against the aforementioned diseases. However, human DDO has not been characterized in detail and, although preclinical studies using experimental rodents are prerequisites for evaluating the in vivo effects of potential inhibitors, the existence of species-specific differences in the properties of human and rodent DDOs is still unclear. Here, the enzymatic activity and characteristics of purified recombinant human DDO were analyzed in detail. The kinetic and inhibitor-binding properties of this enzyme were also compared with those of purified recombinant rat and mouse DDOs. In addition, structural models of human, rat, and mouse DDOs were generated and compared. It was found that the differences among these DDO proteins occur in regions that appear involved in migration of the substrate/product in and out of the active site. In summary, detailed characterization of human DDO was performed and provides useful insights into the use of rats and mice as experimental models for evaluating the in vivo effects of DDO inhibitors.

  10. Effect of pulsed electric field treatment on enzyme kinetics and thermostability of endogenous ascorbic acid oxidase in carrots (Daucus carota cv. Nantes).

    Science.gov (United States)

    Leong, Sze Ying; Oey, Indrawati

    2014-03-01

    The objective of this research was to study the enzyme kinetics and thermostability of endogenous ascorbic acid oxidase (AAO) in carrot purée (Daucus carota cv. Nantes) after being treated with pulsed electric field (PEF) processing. Various PEF treatments using electric field strength between 0.2 and 1.2kV/cm and pulsed electrical energy between 1 and 520kJ/kg were conducted. The enzyme kinetics and the kinetics of AAO thermal inactivation (55-70°C) were described using Michaelis-Menten model and first order reaction model, respectively. Overall, the estimated Vmax and KM values were situated in the same order of magnitude as the untreated carrot purée after being exposed to pulsed electrical energy between 1 and 400kJ/kg, but slightly changed at pulsed electrical energy above 500kJ/kg. However, AAO presented different thermostability depending on the electric field strength applied. After PEF treatment at the electric field strength between 0.2 and 0.5kV/cm, AAO became thermolabile (i.e. increase in inactivation rate (k value) at reference temperature) but the temperature dependence of k value (Ea value) for AAO inactivation in carrot purée decreased, indicating that the changes in k values were less temperature dependent. It is obvious that PEF treatment affects the temperature stability of endogenous AAO. The changes in enzyme kinetics and thermostability of AAO in carrot purée could be related to the resulting carrot purée composition, alteration in intracellular environment and the effective concentration of AAO released after being subjected to PEF treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Chromate reduction by rabbit liver aldehyde oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Banks, R.B.; Cooke, R.T. Jr.

    1986-05-29

    Chromate was reduced during the oxidation of 1-methylnicotinamide chlorine by partially purified rabbit liver aldehyde oxidase. In addition to l-methylnicotinamide, several other electron donor substrates for aldehyde oxidase were able to support the enzymatic chromate reduction. The reduction required the presence of both enzyme and the electron donor substrate. The rate of the chromate reduction was retarded by inhibitors or aldehyde oxidase but was not affected by substrates or inhibitors of xanthine oxidase. These results are consistent with the involvement of aldehyde oxidase in the reduction of chromate by rabbit liver cytosolic enzyme preparations.

  12. Enzyme

    Science.gov (United States)

    Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

  13. KARAKTERISASI ENZIM POLIFENOL OKSIDASE BIJI KAKAO (Theobroma cacao Linn. Characterization of Polyphenol Oxidase Enzyme of Cocoa Beans (Theobroma cacao Linn.

    Directory of Open Access Journals (Sweden)

    G.P. Ganda Putra

    2012-05-01

    max equals to 595,24 U/gram (db of cocoa beans and K equals to 0,20 M; result of SDS- PAGE of enzyme shows protein bands at M� of 11,75; 17,80; 27,80; 36,03 and 131,52 kDa; and finally, optimumcondition of enzyme activity is at the temperature of 53,43oC; pH 5,42 and incubation time of 80,91 minutes. ABSTRAK Telah dilakukan penelitian dengan tujuan untuk: (1 mengetahui karakteristik enzim polifenol oksidase dan (2 menen- tukan kondisi (suhu, pH dan waktu inkubasi optimum aktivitas enzim polifenol oksidase, yang diisolasi dari biji kakao kering. Hasil penelitian berupa kondisi (suhu, pH dan waktu inkubasi optimum aktivitas enzim polifenol oksidase akan diaplikasikan untuk perbaikan mutu biji kakao kering melalui teknik rehidrasi. Penelitian ini dilakukan melalui tahapan: (1 isolasi enzim polifenol oksidase dari 10 sampel biji kakao kering di Provinsi Bali, (2 karakterisasi enzim polifenol oksidase (aktivitas, kinetika enzim, BM dan (3 penentuan kondisi suhu, pH dan waktu inkubasi optimum. Hasil yang diperoleh menunjukkan bahwa: (1 aktivitas enzim polifenol oksidase rata-rata 157,49 ± 58,03 U/gram (bk biji kakao dengan aktivitas maksimum 258,22 U/gram (bk biji kakao dan minimum 59,01 U/gram (bk biji kakao; maks sebesar 595,24 U/gram (bk biji kakao dan K sebesar 0,20 M; hasil SDS-PAGE enzim menunjukkan pita-pita protein yang terbentuk pada BM 11,75; 17,80; 27,80; 36,03 dan 131,52 kDa; dan (2 kondisi optimum aktivitas enzimadalah suhu 53,43oC; pH 5,42 dan waktu inkubasi 80,91 menit.

  14. Analytical development of a binuclear oxo-manganese complex bio-inspired on oxidase enzyme for doping control analysis of acetazolamide.

    Science.gov (United States)

    Machini, Wesley B S; Teixeira, Marcos F S

    2016-05-15

    A bio-inspired electrochemical sensor using a binuclear oxo-manganese complex was evaluated and applied in the detection of a substance associated with doping in sports: acetazolamide (ACTZ). Investigation was made of the influence of different experimental variables on the electrocatalytic oxidation of ACTZ by the bio-inspired sensor, such as pH and interfering species. The bio-inspired sensor showed the best response in the range from 5.00×10(-9) to 7.00×10(-8) mol L(-1) ACTZ, with a linear range from 5.00×10(-9) to 2.50×10(-8) mol L(-1) and a detection limit of 4.76×10(-9) mol L(-1). The sensor exhibited characteristics similar to the Michaelis-Menten model of an enzymatic electrode, due to the use of a multinucleated complex of manganese with μ-oxo units, which was able to mimic the properties of enzymes with manganese as a cofactor in their composition, such as Mn-containing oxidase. The determination of ACTZ with the bio-inspired sensor was evaluated using three different synthetic biological fluids (plasma, saliva, and urine), demonstrating its viability for use with real samples. The analysis of ACTZ in real urine samples using the bio-inspired sensor, simulating the method adopted by the World Anti-Doping Agency, which revealed viable, suggesting a new and promising platform to be used in these analysis.

  15. Novel Roles for the Polyphenol Oxidase Enzyme in Secondary Metabolism and the Regulation of Cell Death in Walnut1[W][OPEN

    Science.gov (United States)

    Araji, Soha; Grammer, Theresa A.; Gertzen, Ross; Anderson, Stephen D.; Mikulic-Petkovsek, Maja; Veberic, Robert; Phu, My L.; Solar, Anita; Leslie, Charles A.; Dandekar, Abhaya M.; Escobar, Matthew A.

    2014-01-01

    The enzyme polyphenol oxidase (PPO) catalyzes the oxidation of phenolic compounds into highly reactive quinones. Polymerization of PPO-derived quinones causes the postharvest browning of cut or bruised fruit, but the native physiological functions of PPOs in undamaged, intact plant cells are not well understood. Walnut (Juglans regia) produces a rich array of phenolic compounds and possesses a single PPO enzyme, rendering it an ideal model to study PPO. We generated a series of PPO-silenced transgenic walnut lines that display less than 5% of wild-type PPO activity. Strikingly, the PPO-silenced plants developed spontaneous necrotic lesions on their leaves in the absence of pathogen challenge (i.e. a lesion mimic phenotype). To gain a clearer perspective on the potential functions of PPO and its possible connection to cell death, we compared the leaf transcriptomes and metabolomes of wild-type and PPO-silenced plants. Silencing of PPO caused major alterations in the metabolism of phenolic compounds and their derivatives (e.g. coumaric acid and catechin) and in the expression of phenylpropanoid pathway genes. Several observed metabolic changes point to a direct role for PPO in the metabolism of tyrosine and in the biosynthesis of the hydroxycoumarin esculetin in vivo. In addition, PPO-silenced plants displayed massive (9-fold) increases in the tyrosine-derived metabolite tyramine, whose exogenous application elicits cell death in walnut and several other plant species. Overall, these results suggest that PPO plays a novel and fundamental role in secondary metabolism and acts as an indirect regulator of cell death in walnut. PMID:24449710

  16. 抑郁症单胺氧化酶A基因活性对表情识别脑功能的影响%Influence of monoamine oxidase A gene and brain function in the dynamic facial expression recognition in depressed patients

    Institute of Scientific and Technical Information of China (English)

    唐勇; 张婧; 姚志剑; 刘海燕; 卢青

    2011-01-01

    目的 应用影像基因组学的原理,探讨单胺氧化酶A基因串联重复序列多态性(MAOA-uVNTR)对抑郁症患者及健康对照不同面部表情识别过程中脑功能的影响.方法 28例抑郁症患者及33例性别比例、年限、受教育年限匹配的健康对照,应用聚合酶链式反应(PCR)技术扩增目的 基因,将61名受试者进行基因型分组,并利用1.5T功能核磁共振成像系统检测每个受试在识别喜悦、悲伤、及中性面部表情视频时的脑激活反应.结果 识别悲伤面部表情时,高活性基因型健康组较低活性基因型健康组左楔叶、左额下回、右额中回、左顶下小叶脑区激活显著增强(P<0.005,K≥10).识别喜悦面部表情时,高活性基因型患者组较低活性基因型患者组左右壳核、左中央后回,右颞上回、右丘脑、左梭状回脑区激活降低(P<0.005,K≥10).结论 高活性基因型与健康人群负性情绪识别的优先激活趋势及抑郁症患者正性情绪的抑制状态均存在关联性,该基因型可能是健康者罹患抑郁症的危险因素之一,同时部分导致该类患者情绪症状较为显著.%Objective To explore the impact of the variable number of tandem repeats of monoamine oxidase A gene (MAOA-uVNTR) on the intensity of brain activation during the recognition of facial expression in patients with depression and healthy controls.Methods 28 cases of depression,as well as 33 healthy controls who were matched in gender, age and years of education were divided into different genotypes with the methods of polymerase chain reaction (PCR) amplification and 1.5% agarose gel electrophoresis separation.61 cases were scanned to compare the intensity of brain activation in the recognition of happy, sad and neutral facial expression.Results In healthy controls,cases with high-activity genotype showed increased activation in left cuneus,left inferior frontal gyrus, right medial frontal gyrus and left inferior

  17. 单胺氧化酶A基因多态性与儿童期虐待对青少年攻击行为的影响%Association of monoamine oxidase A variable number of tandem repeats and child abuse with aggressive behavior among Chinese adolescents

    Institute of Scientific and Technical Information of China (English)

    张芸; 明庆森; 朱熊兆; 蚁金瑶; 姚树桥

    2014-01-01

    目的 探讨单胺氧化酶A串联重复序列(monoamine oxidase A variable number of tandem repeats)基因多态性及儿童期虐待对中国青少年攻击行为影响.方法 采用整群随机抽样法抽取某中学637名年龄13~18岁汉族青少年样本(男388名,女249名),采用儿童创伤经历问卷评定儿童期虐待,采用儿童行为量表评定攻击行为,并从研究对象外周静脉血提取DNA进行MAOA-VNTR基因分型,采用直线回归方法检验儿童期虐待和MAOA-VNTR基因多态性各自对攻击行为的主效应及两者间的交互作用.结果 共有513名(男367名,女146名)进入研究,男性攻击行为平均得分(10.13±6.67)分,女性攻击行为平均得分(9.18 ±6.36)分,不同性别间攻击行为差异无统计学意义(P=0.08).367名男性青少年被试中,MAOA低、高活性组分别为58.3%与41.7%,且不同组间攻击行为得分差异无统计学意义(P=0.93).回归模型显示MAOA基因型对男性青少年攻击行为无预测作用,儿童期虐待经历对攻击行为有显著预测作用(P<0.01),且MAOA基因型与不同类型童年虐待对攻击行为存在显著交互作用(MAOA×虐待总分:P <0.01;MAOA×躯体虐待:P=0.02;MAOA×情感虐待:P <0.01;MAOA×性虐待:P =0.04),MAOA低活性男性在经历儿童期躯体虐待和情感虐待后更易出现攻击倾向;146名女性青少年被试中,MAOA低活性、高活性及杂合子组分别占39.4%、22.5%和38.1%,MAOA不同基因型之间攻击行为得分差异无统计学意义(P=0.69).回归模型显示MAOA基因型对女性青少年攻击行为无预测作用,但儿童期虐待经历对其有显著预测作用(P<0.01),且MAOA与性虐待及MAOA与情感虐待对攻击行为分别存在交互作用(P值分别为0.03和0.04),MAOA低活性女性在受到儿童期性虐待/情感虐待后更易出现攻击倾向.结论 我国13 ~18岁青少年攻击行为受到儿童期虐待经历与MAOA-VNTR基因-环境间交互作用的

  18. [Catecholamines and their metabolic enzymes in the hypothalamus of rats after a flight on the Kosmos-782 biosatellite].

    Science.gov (United States)

    Kvetnanský, R; Tigranian, R A; Torda, T; Babusiková, D; Jahnová, E

    1979-01-01

    The concentration of catecholamines, and activity of enzymes involved in their synthesis (tyrosine hydroxylase and dopamine-beta-hydroxylase) and degradation (monoamine oxidase) were measured in the hypothalamus of rats flown for 19.5 days aboard the biosatellite Cosmos-782, synchronous and vivarium controls sacrificed on R+O and R+25 days. No significant changes in the above parameters of the flight rats were found. The findings give evidence that a prolonged space flight induces no changes in the content, synthesis or degradation of catecholamines in the rat hypothalamus. This seems to indicate that weightlessness does not act as an acute stressor.

  19. Mixed-function oxidase enzyme activity and oxidative stress in lake trout (Salvelinus namaycush) exposed to 3,3{prime},4,4{prime}5-pentachlorobiphenyl (PCB-126)

    Energy Technology Data Exchange (ETDEWEB)

    Palace, V.P. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Zoology; Klaverkamp, J.F.; Lockhart, W.L. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Zoology]|[Department of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.; Metner, D.A.; Muir, D.C.G.; Brown, S.B. [Department of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.

    1996-06-01

    Juvenile lake trout were intraperitoneally injected with corn oil containing nominal concentrations of 0, 0.6, 6.3, or 25 {micro}g [{sup 14}C]-3,3{prime},4,4{prime},5-pentachlorobiphenyl (PCB-126) per gram of body weight. The PCB-126 accumulated in liver in a dose-dependent manner to a sustained concentration by 6 weeks and remained elevated for the 30-week experimental period. Mixed-function oxidase (MFO) enzyme activity was elevated in the two highest dose groups relative to the control group, but not in the low-dose group throughout the 30 weeks. Oxidative stress, measured by the thiobarbituric acid reactive substances test, was correlated with ethoxyresorufin O-deethylase and was elevated in liver of the two highest PCB dose groups but not the low-dose group. The activities of the enzymatic antioxidants superoxide dismutase, catalase, and glutathione peroxidase were unaffected by PCB-126 exposure. The nonenzymatic antioxidants superoxide dismutase, catalase, and glutathione peroxidase were unaffected by PCB-126 exposure. The nonenzymatic antioxidant tocopherol was depleted to approximately 75% of the control concentration in liver of all three PCB-dosed groups. Hepatic ascorbic acid levels were not different in any of the treatment groups. Retinol was depleted by greater than an order of magnitude in liver of the two highest dose groups but not in the los-dose group. This study demonstrates a correlation between hepatic MFO activity and oxidative stress in PCB-exposed lake trout. Tocopherol and retinol may be important mediators of oxidative stress but additional study is required to confirm the antioxidant activity of retinol.

  20. Ability of Kocuria varians LTH 1540 To Degrade Putrescine: Identification and Characterization of a Novel Amine Oxidase.

    Science.gov (United States)

    Callejón, Sara; Sendra, Ramón; Ferrer, Sergi; Pardo, Isabel

    2015-04-29

    This work describes the identification and characterization of an amine oxidase from Kocuria varians LTH 1540 (syn. Micrococcus varians) primarily acting on putrescine. Data from MALDI-TOF MS/MS and the identification of Δ(1)-pyrroline as degradation product from putrescine indicate that the enzyme is a flavin-dependent putrescine oxidase (PuO). Properties of partially purified enzyme have been determined. The enzyme oxidizes diamines, putrescine and cadaverine, and, to a lesser extent, polyamines, such as spermidine, but not monoamines. The kinetic constants (Km and Vmax) for the two major substrates were 94 ± 10 μM and 2.3 ± 0.1 μmol/min·mg for putrescine and 75 ± 5 μM and 0.15 ± 0.02 μmol/min·mg for cadaverine. Optimal temperature and pH were 45 °C and 8.5, respectively. Enzyme was stable until 50 °C. K. varians PuO is sensitive to human flavin-dependent amine oxidase inhibitors and carboxyl-modifying compounds. The new enzyme has been isolated from a bacterial starter used in the manufacture of fermented meat. One of the problems of fermented foods or beverages is the presence of toxic biogenic amines produced by bacteria. The importance of this works lies in the description of a new enzyme able to degrade two of the most abundant biogenic amines (putrescine and cadaverine), the use of which could be envisaged to diminish biogenic amines content in foods in the future.

  1. Berberine target key enzymes and amino acid inibitiors in AD treatment-----creation from berberine-based structure screening

    Directory of Open Access Journals (Sweden)

    Yau Lam

    2014-07-01

    Full Text Available The main components of berberine from coptis have a variety of pharmacological activity include the treatment of neurodegenerative diseases, Alzheimer’s disease (AD. The principle of berberine is inhibiting the lower activity of enzyme and amino acid to prevent (AD. Enzyme like acetylcholinesterase enzyme (AchE, butyrylcholinesterase enzyme (BchE and monoamine oxidase (MAO; Amino acid like beta-amyloid (Aβ. Unfortunately, the single chemical structures of berberine is no significance to regulation effect. As a part of our consideration, the review paper studies on chemically modified and synthesis from berberine-derivatives. Results show that the structures of (23, (10, (86, (52, and (61 have a potential effect for AchE, BuChE and Aβ-amyloid inhibitors for the first time. Especially in (23 and (52 also has better than two western medicine were compared.

  2. [Noradrenaline and the enzymes of its synthesis and breakdown in the rat hypothalamus after a flight on the Kosmos-936 biosatellite].

    Science.gov (United States)

    Torda, T; Kvetnansky, R; Tigranian, R A; Chulman, J; Genin, A M

    1981-01-01

    In the hypothalamus of the weightless and centrifuged rats flown for 18.5 days on board the biosatellite Cosmos-936 the noradrenaline concentration and activity of the enzymes involved in the catecholamine synthesis and degradation were measured. It was found that under the space flight influence the noradrenaline concentration and tyrosine hydroxylase, dopamine-beta-hydroxylase and monoamine oxidase activities remained unaltered. These findings indicate that a prolonged exposure to weightlessness was not a stressogenic agent that could activate the adrenergic system in the rat hypothalamus.

  3. The moderating effect of monoamine oxidase A gene polymorphism in relationship between childhood abuse of male adolescents and externalizing behaviors%单胺氧化酶A基因多态性对男性青少年儿童期虐待与外化性行为关系的调节效应

    Institute of Scientific and Technical Information of China (English)

    明庆森; 姚树桥; 张芸; 陈海燕

    2012-01-01

    Objective To explore the relationship between male adolescents' childhood abuse and externalizing behaviors,and the moderating effect of monoamine oxidase A (MAOA) gene promoter region variable number tandem repeat (VNTR) polymorphism.Methods Through random cluster sampling,352 Han male middle school students from Changsha were tested by Achenbach child behavior checklist-youth self reports (CBCL-YSR)and childhood trauma questionnaire-28 item short form (CTQ-SF),their MAOA genotypes were also identified.A hierarchical multiple regression analysis was used to test the moderating effect.Results ( 1 ) Compared participates with high activity MAOA gene and that with low activity MAOA gene,there were no significant differences on age ( ( 15.82 ± 1.52) vs ( 15.94 ± 1.62 ) ),externalizing behaviors ( ( 15.13 ± 10.14 ) vs ( 14.33 ± 9.70 ) ),total abuse ( (52.59 ± 10.46) vs (51.39 ± 7.56 ) ),emotional abuse( ( 7.63 ± 3.31 ) vs ( 7.11 ± 2.68 ) ),physical abuse ( ( 6.40 ± 2.82) vs (6.12 ± 2.05 ) ),sexual abuse ( ( 6.42 ± 3.24 ) vs ( 5.94 ± 1.72 ) ),emotional neglect ((13.44±5.12) vs (13.16 ±4.83) ),physical neglect( (10.27 ±2.64) vs (10.44±2.53))(t=-1.789~0.678,P > 0.05 ).(2)Except emotional neglect and physical neglect,emotional abuse,physical abuse and sexual abuse could predict externalizing behaviors( Sβ =0.141 ~0.347,P < 0.01 ).(3) MAOA gene was not directly related to externalizing behaviors( Sβ =- 0.023,P > 0.05 ).There was a significant interaction between MAOA gene and emotional abuse( Sβ =-0.148,P < 0.01 ).The interaction between MAOA gene and physical abuse or sexual abuse showed no statistical significance( Sβ =- 0.067,- 0.005,P > 0.05 ).Conclusion MAOA gene polymorphism can moderate the relationship between male adolescents'childhood emotional abuse and externalizing behaviors.%目的 探讨男性青少年的儿童期虐待与外化性行为的关系以及单胺氧化酶A (MAOA)基因启动子区域可变重复序列(VNTR)多态

  4. Arthrobacter P 1, a Fast Growing Versatile Methylotroph with Amine Oxidase as a Key Enzyme in the Metabolism of Methylated Amines

    NARCIS (Netherlands)

    Dijken, J.P. van; Veenhuis, M.; Harder, W.

    1981-01-01

    A facultative methylotrophic bacterium was isolated from enrichment cultures containing methylamine as the sole carbon source. It was tentatively identified as an Arthrobacter species. Extracts of cells grown on methylamine or ethylamine contained high levels of amine oxidase (E.C. 1.4.3) activity.

  5. Lysyl oxidase in colorectal cancer.

    Science.gov (United States)

    Cox, Thomas R; Erler, Janine T

    2013-11-15

    Colorectal cancer is the third most prevalent form of cancer worldwide and fourth-leading cause of cancer-related mortality, leading to ~600,000 deaths annually, predominantly affecting the developed world. Lysyl oxidase is a secreted, extracellular matrix-modifying enzyme previously suggested to act as a tumor suppressor in colorectal cancer. However, emerging evidence has rapidly implicated lysyl oxidase in promoting metastasis of solid tumors and in particular colorectal cancer at multiple stages, affecting tumor cell proliferation, invasion, and angiogenesis. This emerging research has stimulated significant interest in lysyl oxidase as a strong candidate for developing and deploying inhibitors as functional efficacious cancer therapeutics. In this review, we discuss the rapidly expanding body of knowledge concerning lysyl oxidase in solid tumor progression, highlighting recent advancements in the field of colorectal cancer.

  6. Isolated sulfite oxidase deficiency.

    Science.gov (United States)

    Relinque, B; Bardallo, L; Granero, M; Jiménez, P J; Luna, S

    2015-03-10

    Sulfite oxidase deficiency is an uncommon metabolic disease. Only few cases of its isolated form have been reported in the literature. We report a case of severe neonatal onset. A newborn baby of 41 weeks gestational age, weighted at birth of 3240 grams and had an Apgar score of 6-10-10. Fifty-three hours after being born, the baby started with seizures that were refractory to antiepileptic treatment. Brain function was monitored using a-EEG. Laboratory and imaging tests were performed. All of them were consistent with sulfite oxidase deficiency. The diagnosis was confirmed by genetic testing. We highlight the importance of this disease as part of the differential diagnosis of seizures during the neonatal period, as well as the importance of the therapeutic support based on dietary restrictions. It's also remarkable the possibility of prenatal diagnosis by quantifying enzyme activity and it's also possible carrying out DNA mutational analysis.

  7. Enzyme sensor array for the determination of biogenic amines in food samples

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Jana [University of Greifswald, Institute for Chemistry and Biochemistry (Germany); Wittmann, Christine [Fachhochschule Neubrandenburg, Department of Technology (Germany)

    2002-01-01

    An enzyme sensor array for the simultaneous determination of the three biogenic amines (histamine, tyramine and putrescine) by pattern recognition using an artificial neural network and its application to different food samples is described. A combination of a monoamine oxidase, a tyramine oxidase and a diamine oxidase (with specific activities sufficient for rapid detection) are immobilised each on a separate screen-printed thick-film electrode via transglutaminase and glutaraldehyde to compare these cross-linking reagents with regard to their suitability. To calculate the amount of a specific biogenic amine, the raw data from multichannel software were transferred to a neural network. The sensor array takes 20 min to complete (excluding statistical data analysis) with only one extraction and subsequent neutralisation step required prior to sensor measurement. The lower detection limits with the enzyme sensor were 10 mg/kg for histamine and tyramine, and 5 mg/kg for putrescine with a linear range up to 200 mg/kg for histamine and tyramine and 100 mg/kg for putrescine. The application area of the enzyme sensor array was tested from fish to meat products, sauerkraut, beer, dairy products, wine and further fermented foods and compared with the data of conventional LC analyses (mean correlation coefficient: 0.854). (orig.)

  8. Mild exposure of RIN-5F β-cells to human islet amyloid polypeptide aggregates upregulates antioxidant enzymes via NADPH oxidase-RAGE: An hormetic stimulus

    Directory of Open Access Journals (Sweden)

    Elisabetta Borchi

    2014-01-01

    Full Text Available The presence of amyloid aggregates of human islet amyloid polypeptide (hIAPP, a hallmark of type 2 diabetes, contributes to pancreatic β-cell impairment, where oxidative stress plays a key role. A contribution of NADPH oxidase to reactive oxygen species (ROS generation after cell exposure to micromolar concentrations of hIAPP aggregates has been suggested. However, little is known about β-cells exposure to lower amounts of hIAPP aggregates, similar to those found in human pancreas. Thus, we aimed to investigate the events resulting from RIN-5F cells exposure to nanomolar concentrations of toxic hIAPP aggregates. We found an early and transient rise of NADPH oxidase activity resulting from increased Nox1 expression following the engagement of receptor for advanced glycation end-products (RAGE by hIAPP aggregates. Unexpectedly, NADPH oxidase activation was not accompanied by a significant ROS increase and the lipoperoxidation level was significantly reduced. Indeed, cell exposure to hIAPP aggregates affected the antioxidant defences, inducing a significant increase of the expression and activity of catalase and glutathione peroxidase. We conclude that exposure of pancreatic β-cells to nanomolar concentrations of hIAPP aggregates for a short time induces an hormetic response via the RAGE-Nox1 axis; the latter stimulates the enzymatic antioxidant defences that preserve the cells against oxidative stress damage.

  9. Involvement of a new enzyme, glyoxal oxidase, in extracellular H/sub 2/O/sub 2/ production by Phanerochaete chrysosporium

    Energy Technology Data Exchange (ETDEWEB)

    Kersten, P.J.; Kirk, K.

    1987-05-01

    The importance of extracellular H/sub 2/O/sub 2/ in lignin degradation has become increasingly apparent with the recent discovery of H/sub 2/O/sub 2/-requiring ligninases produced by white-rot fungi. Here the authors describe a new H/sub 2/O/sub 2/-producing activity of Phanerochaete chrysosporium that involves extracellular oxidases able to use simple aldehyde, ..cap alpha..-hydroxycarbonyl, or..cap alpha..-dicarbonyl compounds as substrates. The activity is expressed during secondary metabolism, when the ligninases are also expressed. Analytical isoelectric focusing of the extracellular proteins, followed by activity staining, indicated that minor proteins with broad substrate specificities are responsible for the oxidase activity. Two of the oxidase substrates, glyoxal and methylglyoxal, were also identified, as their quinoxaline derivatives, in the culture fluid as secondary metabolites. The significance of these findings is discussed with respect to lignin degradation and other proposed systems for H/sub 2/O/sub 2/ production in P. chrysosporium.

  10. Flavoprotein oxidases : classification and applications

    NARCIS (Netherlands)

    Dijkman, Willem P.; de Gonzalo, Gonzalo; Mattevi, Andrea; Fraaije, Marco W.

    2013-01-01

    This review provides an overview of oxidases that utilise a flavin cofactor for catalysis. This class of oxidative flavoenzymes has shown to harbour a large number of biotechnologically interesting enzymes. Applications range from their use as biocatalysts for the synthesis of pharmaceutical compoun

  11. New recombinant cyclohexylamine oxidase variants for deracemization of secondary amines by orthogonally assaying designed mutants with structurally diverse substrates

    Science.gov (United States)

    Li, Guangyue; Yao, Peiyuan; Cong, Peiqian; Ren, Jie; Wang, Lei; Feng, Jinhui; Lau, Peter C. K.; Wu, Qiaqing; Zhu, Dunming

    2016-05-01

    To further expand the substrate range of the cyclohexylamine oxidase (CHAO) from Brevibacterium oxydans, a library of diverse mutants was created and assayed toward a group of structurally diverse substrates. Among them, mutants T198A and M226A exhibited enhanced activity relative to wt CHAO for most (S)-enantiomers of primary amines and some secondary amines. While mutants T198I, L199I, L199F, M226I and M226T were more active than wt CHAO toward the primary amines, mutants T198F, L199T, Y321A, Y321T, Y321I and Y321F enhanced the enzyme activity toward the secondary amines. In particular, mutant Y321I displayed an enhanced catalytic efficiency toward 1-(4-methoxybenzyl)-1, 2, 3, 4, 5, 6, 7, 8-octahydroisoquinoline (13). Whereas a double mutant, Y321I/M226T, acted on (S)-N-(prop-2-yn-1-yl)-2, 3-dihydro-1H-inden-1-amine [(S)-8]. Since (R)-8 is an irreversible inhibitor of monoamine oxidase and (S)-13 is an intermediate of dextromethorphan, a cough suppressant drug, deracemizations of 8 and 13 were carried out with crude enzyme extracts of the respective mutants. This resulted in 51% and 78% isolated yields of (R)-8 and (S)-13, respectively, each with high enantiomeric excess (93% and 99% ee). The results demonstrated the application potential of the evolved CHAO mutants in drug synthesis requiring chiral secondary amines.

  12. Spectrophotometric Assay of Immobilized Glucose Oxidase

    Directory of Open Access Journals (Sweden)

    Nojan Noorbehesht

    2016-06-01

    Full Text Available Enzyme results in change the substrate of product. Each enzyme may act on specific substrates, resulting in product or different products. The enzyme glucose oxidase (GOX is a bio catalyst. It accelerates the process of transforming glucose into hydrogen peroxide (H2O2 . These enzymes are used in the chemical industry, food industry, cosmetics and kits for diagnosis of glucose. There are many researches about immobilizations of Glucose Oxide to increase specifications such as repeated use, recovery, stability, shelf life and other features In this work, glucose oxidase enzyme using covalent bonding is placed on the carrier of carbon nanotubes. In this study, multi-walled carbon nanotubes have been used as adsorbents. Also, carbon nanotubes have been functionalized by sulfuric acid and nitric acid with a high concentration. Glucose oxidase is a biological biocatalyst enzyme. It accelerates changing glucose to H2O2. This enzyme is used in the chemical industry, food industry, cosmetics and glucose diagnostic kits. For example, as a result of ongoing research working focuses on the development of glucose biosensors, GOX in practice as standard enzyme has been revealed for immobilization of oxidative enzyme.GOX correct fixation on the MWNTs carrier is a way to reuse enzyme and miniature of biosensor devices and structures. In this study, a spectrophotometer was used to determine the absorbance of the enzyme glucose oxidase (GOX to review its activities after stabilizing the carbon nanotubes.

  13. Coupling of electron transfer with proton transfer at heme a and Cu(A) (redox Bohr effects) in cytochrome c oxidase. Studies with the carbon monoxide inhibited enzyme.

    Science.gov (United States)

    Capitanio, N; Capitanio, G; Minuto, M; De Nitto, E; Palese, L L; Nicholls, P; Papa, S

    2000-05-30

    A study is presented on the coupling of electron transfer with proton transfer at heme a and Cu(A) (redox Bohr effects) in carbon monoxide inhibited cytochrome c oxidase isolated from bovine heart mitochondria. Detailed analysis of the coupling number for H(+) release per heme a, Cu(A) oxidized (H(+)/heme a, Cu(A) ratio) was based on direct measurement of the balance between the oxidizing equivalents added as ferricyanide to the CO-inhibited fully reduced COX, the equivalents of heme a, Cu(A), and added cytochrome c oxidized and the H(+) released upon oxidation and all taken up back by the oxidase upon rereduction of the metal centers. One of two reductants was used, either succinate plus a trace of mitochondrial membranes (providing a source of succinate-c reductase) or hexaammineruthenium(II) as the chloride salt. The experimental H(+)/heme a, Cu(A) ratios varied between 0.65 and 0.90 in the pH range 6.0-8.5. The pH dependence of the H(+)/heme a, Cu(A) ratios could be best-fitted by a function involving two redox-linked acid-base groups with pK(o)-pK(r) of 5.4-6.9 and 7.3-9.0, respectively. Redox titrations in the same samples of the CO-inhibited oxidase showed that Cu(A) and heme a exhibited superimposed E'(m) values, which decreased, for both metals, by around 20 mV/pH unit increase in the range 6.0-8.5. A model in which oxido-reduction of heme a and Cu(A) are both linked to the pK shifts of the two acid-base groups, characterized by the analysis of the pH dependence of the H(+)/heme a, Cu(A) ratios, provided a satisfactory fit for the pH dependence of the E'(m) of heme a and Cu(A). The results presented are consistent with a primary involvement of the redox Bohr effects shared by heme a and Cu(A) in the proton-pumping activity of cytochrome c oxidase.

  14. Lysyl oxidase in colorectal cancer

    DEFF Research Database (Denmark)

    Cox, Thomas R; Erler, Janine T

    2013-01-01

    Colorectal cancer is the third most prevalent form of cancer worldwide and fourth-leading cause of cancer-related mortality, leading to ~600,000 deaths annually, predominantly affecting the developed world. Lysyl oxidase is a secreted, extracellular matrix-modifying enzyme previously suggested...... to act as a tumor suppressor in colorectal cancer. However, emerging evidence has rapidly implicated lysyl oxidase in promoting metastasis of solid tumors and in particular colorectal cancer at multiple stages, affecting tumor cell proliferation, invasion, and angiogenesis. This emerging research has...... advancements in the field of colorectal cancer....

  15. Deuterium kinetic isotope effects in heterotetrameric sarcosine oxidase from Corynebacterium sp. U-96: the anionic form of the substrate in the enzyme-substrate complex is a reactive species.

    Science.gov (United States)

    Saito, Mutsumi; Itoh, Ai; Suzuki, Haruo

    2012-06-01

    Heterotetrameric sarcosine oxidase is a flavoprotein that catalyses the oxidative demethylation of sarcosine. It is thought that the dehydrogenated substrate is the anionic form of sarcosine. To verify this assumption, the rate of flavin-adenine dinucleotide (FAD) reduction (k(red)) was analysed using protiated and deuterated sarcosine (N-methyl-d(3)-Gly) at various pH values using stopped-flow method. By increasing the pH from 6.2 to 9.8, k(red) increased for both substrates and reached a plateau, but the pK(a) value (reflecting the ionization of the enzyme-substrate complex) was 6.8 and 7.1 for protiated and deuterated sarcosine, respectively, and the kinetic isotope effect of k(red) decreased from approximately 19 to 8, indicating deprotonation of the bound sarcosine. The k(red)/K(d) (K(d), sarcosine dissociation constant) increased with increasing pH and reached a plateau. The pK (reflecting the ionization of free enzyme or free sarcosine) was 7.0 for both substrates, suggesting deprotonation of the βLys358 residue, which has a pK(a) of 6.7, as the pK(a) of the free sarcosine amine proton was determined to be approximately 10.1. These results indicate that the amine proton of sarcosine is transferred to the unprotonated Lys residue in the enzyme-substrate complex.

  16. 含有Ag颗粒的高灵敏度葡萄糖氧化酶电极的研制%A HIGHLY SENSITIVE ENZYME ELECTRODE BY GLUCOSE OXIDASE IMMOBILIZED WITHIN Ag SOL

    Institute of Scientific and Technical Information of China (English)

    张改莲; 张金芳; 唐芳琼

    2000-01-01

    研制了含有nm级Ag颗粒的葡萄糖氧化酶电极.结果表明,该电极具有很大的响应电流,在相同的条件下,其响应电流比文献所报导的含有Au或SiO2的酶电极响应电流大.当颗粒粒径为4.3~7.8nm时,酶电极响应电流随粒径的增大而增大;而当粒径继续增大时,其响应电流则随粒径的增大而减小.对Ag颗粒在酶电极中的作用机理也进行了初步探讨.%An amperometric enzyme electrode based on immobilization of glucose oxidase(GOD) within silver(Ag) nanoparticles is presented. The enzyme electrodes are platinum electrodes covered with a membrane containing GOD and Ag nanoparticles. The results show that this kind of enzyme electrodes possess higher sensitivity than those containing Au or SiO2 nanoparticles. Comparing the response current of these Ag-GOD electrodes, it is found that the sensitivity of the enzyme electrodes increases with increasing Ag size in the case of 4.3-7.8nm. In the case of Ag size increasing continously, the situation is different, the enzyme electrodes have lower sensitivity with increasing Ag size. The mechanism of this phenomenon is studied and discussed on the basis of the ability of Ag nanoparticles transfer electron and the adsorption of GOD onto ultrafine particles.

  17. Ascorbate oxidase: the unexpected involvement of a 'wasteful enzyme' in the symbioses with nitrogen-fixing bacteria and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Balestrini, Raffaella; Ott, Thomas; Güther, Mike; Bonfante, Paola; Udvardi, Michael K; De Tullio, Mario C

    2012-10-01

    Ascorbate oxidase (AO, EC 1.10.3.3) catalyzes the oxidation of ascorbate (AsA) to yield water. AO over-expressing plants are prone to ozone and salt stresses, whereas lower expression apparently confers resistance to unfavorable environmental conditions. Previous studies have suggested a role for AO as a regulator of oxygen content in photosynthetic tissues. For the first time we show here that the expression of a Lotus japonicus AO gene is induced in the symbiotic interaction with both nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungi. In this framework, high AO expression is viewed as a possible strategy to down-regulate oxygen diffusion in root nodules, and a component of AM symbiosis. A general model of AO function in plants is discussed. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  18. [Monoamines stimulations in experimental carcinogenesis].

    Science.gov (United States)

    Popov, I; Spuzić, I; Rakić, Lj

    1994-01-01

    Facts about the role of CNS monoamines in cancerogenesis have been accumulated for many years. The aim of the present study was to investigate the effect of interaction of psychoactive drug (Piracetam) and other treatments on survival time of tumour-bearing rats. 138 Wistar rats were used in the experiment. The animals were injected 1% 3--Methilcholantren suspension in 10% Tylose, s.c. under the dorsal skin of the neck in a dose of 3 mg/animal. Within 4-9 months after a single injection, the rats developed tumours at the site of injection. The surgical removal was performed when tumours reached the size of 1-3 cm. After surgical extirpation of tumours different groups of animals were treated by cyclophosphamide (s.c. one-time dose of 50 mg/kg for female and 100 mg/kg for male) or by psychoactive drug (Piracetam) administrated by GE tube 5 time/week, 100 mg/kg. Autopsy and histological examinations were carried out in all animals. Survival time (> 120 days) was the greatest in group B (Piracetam, after surgical removal of tumours) 81.2%, and group C (Cyclophosphamid, after surgical removal of tumours) 68.8% and in group A (only surgical removal of tumours) 50%. In group B the incidence of metastases was the smallest (87.1% of animals were without metastases), compared with group C (45.4% of animals were without metastases) and group A (27.3% of animals were without metastases). The diference is statistically significant. The mechanism of antineoplastic effect of Piracetam consisted of the interaction of influences both on metabolism of the Central nervous system and the tumour. Probably, it is the neurotransmitter modulation that had its effect on carcinogenesis not only by regulation/disregulation of brain homeostasis, but also via direct effect on intracellular processes during cell development and differentation.

  19. Flavin-Dependent Enzymes in Cancer Prevention

    Directory of Open Access Journals (Sweden)

    Danuta Wojcieszyńska

    2012-12-01

    Full Text Available Statistical studies have demonstrated that various agents may reduce the risk of cancer’s development. One of them is activity of flavin-dependent enzymes such as flavin-containing monooxygenase (FMOGS-OX1, FAD-dependent 5,10-methylenetetrahydrofolate reductase and flavin-dependent monoamine oxidase. In the last decade, many papers concerning their structure, reaction mechanism and role in the cancer prevention were published. In our work, we provide a more in-depth analysis of flavin-dependent enzymes and their contribution to the cancer prevention. We present the actual knowledge about the glucosinolate synthesized by flavin-containing monooxygenase (FMOGS-OX1 and its role in cancer prevention, discuss the influence of mutations in FAD-dependent 5,10-methylenetetrahydrofolate reductase on the cancer risk, and describe FAD as an important cofactor for the demethylation of histons. We also present our views on the role of riboflavin supplements in the prevention against cancer.

  20. Implication for functions of the ectopic adipocyte copper amine oxidase (AOC3 from purified enzyme and cell-based kinetic studies.

    Directory of Open Access Journals (Sweden)

    Sam H Shen

    Full Text Available AOC3 is highly expressed in adipocytes and smooth muscle cells, but its function in these cells is currently unknown. The in vivo substrate(s of AOC3 is/are also unknown, but could provide an invaluable clue to the enzyme's function. Expression of untagged, soluble human AOC3 in insect cells provides a relatively simple means of obtaining pure enzyme. Characterization of enzyme indicates a 6% titer for the active site 2,4,5-trihydroxyphenylalanine quinone (TPQ cofactor and corrected k(cat values as high as 7 s(-1. Substrate kinetic profiling shows that the enzyme accepts a variety of primary amines with different chemical features, including nonphysiological branched-chain and aliphatic amines, with measured k(cat/K(m values between 10(2 and 10(4 M(-1 s(-1. K(m(O(2 approximates the partial pressure of oxygen found in the interstitial space. Comparison of the properties of purified murine to human enzyme indicates k(cat/K(m values that are within 3 to 4-fold, with the exception of methylamine and aminoacetone that are ca. 10-fold more active with human AOC3. With drug development efforts investigating AOC3 as an anti-inflammatory target, these studies suggest that caution is called for when screening the efficacy of inhibitors designed against human enzymes in non-transgenic mouse models. Differentiated murine 3T3-L1 adipocytes show a uniform distribution of AOC3 on the cell surface and whole cell K(m values that are reasonably close to values measured using purified enzymes. The latter studies support a relevance of the kinetic parameters measured with isolated AOC3 variants to adipocyte function. From our studies, a number of possible substrates with relatively high k(cat/K(m have been discovered, including dopamine and cysteamine, which may implicate a role for adipocyte AOC3 in insulin-signaling and fatty acid metabolism, respectively. Finally, the demonstrated AOC3 turnover of primary amines that are non-native to human tissue suggests

  1. Status and Advances of Researches on GA 20-oxidases

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Chen Xiaoyang; Li Hui; Guo Hai

    2003-01-01

    GA 20-oxidase, the most important limiting enzyme, can catalyze a series of oxidization of GA biosynthesis pathwayfrom GA12 to GA9 and from GA53 to GA20 in the higher plants. This paper reviews the studies on the characters of GA 20-oxidase,the gene and the protein of GA 20-oxidase and the regulation of GA 20-oxidase gene expression in recent years. At the same time,the prospects for the gene transformation of GA 20-oxidase in agriculture, forestry and horticulture are also discussed.

  2. Effect of spermidine and its metabolites on the activity of pea seedlings diamine oxidase and the problems of biosensing of biogenic amines with this enzyme.

    Science.gov (United States)

    Kivirand, K; Sõmerik, H; Oldekop, M-L; Rebane, R; Rinken, T

    2016-01-01

    Spermidine is one of the several biogenic amines, produced during the microbial decarboxylation of proteins. Individual biogenic amines in the formed mixtures are frequently analyzed with oxygen sensor based biosensors, as their content serves as a good biomarker for the determination of food quality. In these biosensors, diamine oxidase from pea seedlings (PSAO), catalyzing the oxidation of various biogenic amines by dissolved oxygen is commonly used for the bio-recognition of amines. However, in the presence of spermidine and/or its metabolite 1,3-diaminopropane, the activity of PSAO and the sensitivity of PSAO-based biosensors decrease due to inhibition. The inhibition constant of soluble spermidine, acting as an inhibiting substrate toward PSAO, was found to be (40±15) mM in freshly prepared solution and (0.28±0.05) mM in solution, incubated 30 days at room temperature. The inhibition constant of 1,3-diaminopropane, acting as a competitive inhibitor, was (0.43±0.12) mM as determined through the oxidation reaction of cadaverine. The metabolic half-life of soluble spermidine was 7 days at room temperature and 186 days at 4 °C. The kinetic measurements were carried out with an oxygen sensor; the composition of the solution of degraded spermidine was analyzed with MS.

  3. Peptides derived from the copper-binding region of lysyl oxidase exhibit antiangiogeneic properties by inhibiting enzyme activity: an in vitro study.

    Science.gov (United States)

    Mohankumar, Arun; Renganathan, Bhuvanasundar; Karunakaran, Coral; Chidambaram, Subbulakshmi; Konerirajapuram Natarajan, Sulochana

    2014-11-01

    Despite the rigorous research on abnormal angiogenesis, there is a persistent need for the development of new and efficient therapies against angiogenesis-related diseases. The role of Lysyl oxidase (LOX) in angiogenesis and cancer has been established in prior studies. Copper is known to induce the synthesis of LOX, and hence regulates its activity. Hypoxia-induced metastasis is dependent on LOX expression and activity. It has been believed that the inhibition of LOX would be a therapeutic strategy to inhibit angiogenesis. To explore this, we designed peptides (M peptides) from the copper-binding region of LOX and hypothesized them to modulate LOX. The peptides were characterized, and their copper-binding ability was confirmed by mass spectrometry. The M peptides were found to reduce the levels of intracellular copper when the cells were co-treated with copper. The peptides showed promising effect on aortic LOX, recombinant human LOX and LOX produced by human umbilical vein endothelial cells (HUVECs). The study also explores the effect of these peptides on copper and hypoxia-stimulated angiogenic response in HUVECs. It was found that the M peptides inhibited copper/hypoxia-induced LOX activity and inhibited stimulated HUVEC tube formation and migration. This clearly indicated the potential of M peptides in inhibiting angiogenesis, highlighting their role in the formulation of drugs for the same.

  4. Rv2969c, essential for optimal growth in Mycobacterium tuberculosis, is a DsbA-like enzyme that interacts with VKOR-derived peptides and has atypical features of DsbA-like disulfide oxidases

    Energy Technology Data Exchange (ETDEWEB)

    Premkumar, Lakshmanane, E-mail: p.lakshmanane@imb.uq.edu.au; Heras, Begoña; Duprez, Wilko; Walden, Patricia; Halili, Maria; Kurth, Fabian; Fairlie, David P.; Martin, Jennifer L., E-mail: p.lakshmanane@imb.uq.edu.au [University of Queensland, St Lucia, QLD 4067 (Australia)

    2013-10-01

    The gene product of M. tuberculosis Rv2969c is shown to be a disulfide oxidase enzyme that has a canonical DsbA-like fold with novel structural and functional characteristics. The bacterial disulfide machinery is an attractive molecular target for developing new antibacterials because it is required for the production of multiple virulence factors. The archetypal disulfide oxidase proteins in Escherichia coli (Ec) are DsbA and DsbB, which together form a functional unit: DsbA introduces disulfides into folding proteins and DsbB reoxidizes DsbA to maintain it in the active form. In Mycobacterium tuberculosis (Mtb), no DsbB homologue is encoded but a functionally similar but structurally divergent protein, MtbVKOR, has been identified. Here, the Mtb protein Rv2969c is investigated and it is shown that it is the DsbA-like partner protein of MtbVKOR. It is found that it has the characteristic redox features of a DsbA-like protein: a highly acidic catalytic cysteine, a highly oxidizing potential and a destabilizing active-site disulfide bond. Rv2969c also has peptide-oxidizing activity and recognizes peptide segments derived from the periplasmic loops of MtbVKOR. Unlike the archetypal EcDsbA enzyme, Rv2969c has little or no activity in disulfide-reducing and disulfide-isomerase assays. The crystal structure of Rv2969c reveals a canonical DsbA fold comprising a thioredoxin domain with an embedded helical domain. However, Rv2969c diverges considerably from other DsbAs, including having an additional C-terminal helix (H8) that may restrain the mobility of the catalytic helix H1. The enzyme is also characterized by a very shallow hydrophobic binding surface and a negative electrostatic surface potential surrounding the catalytic cysteine. The structure of Rv2969c was also used to model the structure of a paralogous DsbA-like domain of the Ser/Thr protein kinase PknE. Together, these results show that Rv2969c is a DsbA-like protein with unique properties and a limited

  5. Immobilisation and characterisation of biocatalytic co-factor recycling enzymes, glucose dehydrogenase and NADH oxidase, on aldehyde functional ReSynTM polymer microspheres

    CSIR Research Space (South Africa)

    Twala, BV

    2012-03-01

    Full Text Available The use of enzymes in industrial applications is limited by their instability, cost and difficulty in their recovery and re-use. Immobilisation is a technique which has been shown to alleviate these limitations in biocatalysis. Here we describe...

  6. Monoamine theories of depression: historical impact on biomedical research.

    Science.gov (United States)

    Mulinari, Shai

    2012-01-01

    Monoamine theories associate depression with reduced brain monoamine levels. These theories achieved broad popularity in the mid-1960s. The present article reviews the historical development of monoamine theories and their subsequent impact on biomedical research. Alleged divisions between West European and US researchers over competing versions of the theories are investigated using bibliometrics. Subsequently, the application of monoamine theories in the NIMH Collaborative Program on the Psychobiology of Depression is covered. The article argues that the impact of monoamine theories is best explained by the ability of researchers, governmental agencies, and pharmaceutical companies to invoke theories that advance various projects and agendas.

  7. Galactose oxidase nanoaggregates: Preparation and characterization

    OpenAIRE

    Mamta Sharma; Minakshi Sharma

    2016-01-01

    Galctose oxidase nanoaggregates have been prepared by chemical desolvation method involving the crosslinkng agent glutaraldehyde. These enzyme nanoagregates have been characterized by transmission electron microscopy(TEM), UV visible spectroscopy, Fourier transform infrared spectroscopy (FTIR). TEM reveals the globular spherical nanostructured form upto the range of 20nm. UV visible spectroscopy of galactose oxidase nanoaggregates shows maximum absorption peak at 237nm. FTIR spectra obtaine...

  8. Monoamine transporters: Insights from molecular dynamics simulations

    Directory of Open Access Journals (Sweden)

    Julie eGrouleff

    2015-10-01

    Full Text Available The human monoamine transporters facilitate the reuptake of the neurotransmitters serotonin, dopamine, and norepinephrine from the synaptic cleft. Imbalance in monoaminergic neurotransmission is linked to various diseases including major depression, attention deficit hyperactivity disorder, schizophrenia and Parkinson’s disease. Inhibition of the monoamine transporters is thus an important strategy for treatment of such diseases. The monoamine transporters are sodium-coupled transport proteins belonging to the neurotransmitter/Na+ symporter (NSS family, and the publication of the first high-resolution structure of a NSS family member, the bacterial leucine transporter LeuT, in 2005, proved to be a major stepping stone for understanding this family of transporters. Structural data allows for the use of computational methods to study the monoamine transporters, which in turn has led to a number of important discoveries. The process of substrate translocation across the membrane is an intrinsically dynamic process. Molecular dynamics simulations, which can provide atomistic details of molecular motion on ns to ms timescales, are therefore well-suited for studying transport processes. In this review, we outline how molecular dynamics simulations have provided insight into the large scale motions associated with transport of the neurotransmitters, as well as the presence of external and internal gates, the coupling between ion and substrate transport, and differences in the conformational changes induced by substrates and inhibitors.

  9. Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 2. Induction of mixed function oxidase enzymes in barramundi, Lates calcarifer, a tropical fish species.

    Science.gov (United States)

    Mercurio, Philip; Burns, Kathryn A; Cavanagh, Joanne

    2004-05-01

    An increasing number of vegetable-based oils are being developed as environmentally friendly alternatives to petroleum products. However, toxicity towards key tropical marine species has not been investigated. In this study we used laboratory-based biomarker induction experiments to compare the relative stress of a vegetable-based lubricating oil for marine 2-stroke engines with its mineral oil-based counterpart on tropical fish. The sub-lethal stress of 2-stoke outboard lubricating oils towards the fish Lates calcarifer (barramundi) was examined using liver microsomal mixed function oxidase (MFO) induction assays. This study is the first investigation into the use of this key commercial species in tropical North Queensland, Australia in stress assessment of potential hydrocarbon pollution using ethoxyresorufin O-deethylase (EROD) induction. Our results indicated that barramundi provide a wide range of inducible rates of EROD activity in response to relevant organic stressors. The vegetable- and mineral-based lubricants induced significant EROD activity at 1.0 mg kg(-1) and there was no significant difference between the two oil treatments at that concentration. At increasing concentrations of 2 and 3 mg kg(-1), the mineral-based lubricant resulted in slightly higher EROD activity than the vegetable-based lubricant. The EROD activity of control and treated barramundi are found to be within ranges for other species from temperate and tropical environments. These results indicate that vegetable-based lubricants may be less stressful to barramundi than their mineral counterparts at concentrations of lubricant > or =2 mg kg(-1). There is great potential for this species to be used in the biomonitoring of waterways around tropical North Queensland and SE Asia.

  10. Alkylamino derivatives of 4-aminomethylpyridine as inhibitors of copper-containing amine oxidases.

    Science.gov (United States)

    Bertini, Vincenzo; Buffoni, Franca; Ignesti, Giovanni; Picci, Nevio; Trombino, Sonia; Iemma, Francesca; Alfei, Silvana; Pocci, Marco; Lucchesini, Francesco; De Munno, Angela

    2005-02-10

    The first substratelike, reversible inhibitors of different copper amine oxidases (CAOs) with IC50 (M) as low as 2.0 x 10(-8) corresponding to derivatives of 4-aminomethylpyridine with alkoxy (1a-d), alkylthio (2a,b), and alkylamino (3a-e, 4a-j) groups in the positions 3 and 5 have been prepared and studied. The inhibitors 1a-d are active on benzylamine oxidase and semicarbazide-sensitive amine oxidase and are very selective with respect to diamine oxidase, lysyl oxidase, and monoamine oxidases. The inhibitors 2a,b are selective for benzylamine oxidase whereas 2a is also a new type of good substrate of diamine oxidase. The inhibitors 3a-e and 4a-j are substratelike, reversible, nonselective inhibitors of various CAOs including pea seedling amine oxidase and Hansenula polymorpha amine oxidase, whose enzymatic sites are known from X-ray structure determinations. The inhibitors 3b,c and 4b,c are excellent substratelike tools for studies correlating CAOs that afford crystals suitable for X-ray structure determinations with CAOs from mammals.

  11. A role for NADPH oxidase in antigen presentation

    Directory of Open Access Journals (Sweden)

    Gail J Gardiner

    2013-09-01

    Full Text Available The nicotinamide adenine dinucleotide phosphate (NADPH oxidase expressed in phagocytes is a multi-subunit enzyme complex that generates superoxide (O2.-. This radical is an important precursor of hydrogen peroxide (H2O2 and other reactive oxygen species (ROS needed for microbicidal activity during innate immune responses. Inherited defects in NADPH oxidase give rise to chronic granulomatous disease (CGD, a primary immunodeficiency characterized by recurrent infections and granulomatous inflammation. Interestingly, CGD, CGD carrier status, and oxidase gene polymorphisms have all been associated with autoinflammatory and autoimmune disorders, suggesting a potential role for NADPH oxidase in regulating adaptive immune responses. Here, NADPH oxidase function in antigen processing and presentation is reviewed. NADPH oxidase influences dendritic cell (DC crosspresentation by major histocompatibility complex class I molecules (MHC-I through regulation of the phagosomal microenvironment, while in B lymphocytes, NADPH oxidase alters epitope selection by major histocompatibility complex class II molecules (MHC-II.

  12. Exercise Benefits Brain Function: The Monoamine Connection

    OpenAIRE

    Tzu-Wei Lin; Yu-Min Kuo

    2013-01-01

    The beneficial effects of exercise on brain function have been demonstrated in animal models and in a growing number of clinical studies on humans. There are multiple mechanisms that account for the brain-enhancing effects of exercise, including neuroinflammation, vascularization, antioxidation, energy adaptation, and regulations on neurotrophic factors and neurotransmitters. Dopamine (DA), noradrenaline (NE), and serotonin (5-HT) are the three major monoamine neurotransmitters that are known...

  13. MUTATIONS IN THE FAD-BINDING FOLD OF ALCOHOL OXIDASE FROM HANSENULA-POLYMORPHA

    NARCIS (Netherlands)

    DEHOOP, M; ASGEIRSDOTTIR, S; BLAAUW, M; VEENHUIS, M; CREGG, J; GLEESON, M; AB, G

    1991-01-01

    Alcohol oxidase of methylotrophic yeast is an FAD-containing enzyme. When in its active form, the enzyme is an octamer and located in the peroxisomes. To study the importance of FAD-binding on the activity, octamerization and intracellular localization of the enzyme, alcohol oxidase of Hansenula pol

  14. Mediator-free interaction of glucose oxidase, as model enzyme for immobilization, with Al-doped and undoped ZnO thin films laser-deposited on polycarbonate supports.

    Science.gov (United States)

    V T K P, Fidal; Inguva, Saikumar; Krishnamurthy, Satheesh; Marsili, Enrico; Mosnier, Jean-Paul; T S, Chandra

    2017-01-01

    Al doped and undoped ZnO thin films were deposited by pulsed-laser deposition on polycarbonate sheets. The films were characterized by optical transmission, Hall effect measurement, XRD and SEM. Optical transmission and surface reflectometry studies showed good transparency with thicknesses ∼100nm and surface roughness of 10nm. Hall effect measurements showed that the sheet carrier concentration was -1.44×10(15)cm(-2) for AZO and -6×10(14)cm(-2) for ZnO. The films were then modified by drop-casting glucose oxidase (GOx) without the use of any mediators. Higher protein concentration was observed on ZnO as compared to AZO with higher specific activity for ZnO (0.042Umg(-1)) compared to AZO (0.032Umg(-1)), and was in agreement with cyclic voltemmetry (CV). X-ray photoelectron spectroscopy (XPS) suggested that the protein was bound by dipole interactions between AZO lattice oxygen and the amino group of the enzyme. Chronoamperometry showed sensitivity of 5.5μAmM(-1)cm(-2) towards glucose for GOx/AZO and 2.2μAmM(-1)cm(-2) for GOx/ZnO. The limit of detection (LoD) was 167μM of glucose for GOx/AZO, as compared to 360μM for GOx/ZnO. The linearity was 0.28-28mM for GOx/AZO whereas it was 0.6-28mM for GOx/ZnO with a response time of 10s. Possibly due to higher enzyme loading, the decrease of impedance in presence of glucose was larger for GOx/ZnO as compared to GOx/AZO in electrochemical impedance spectroscopy (EIS). Analyses with clinical blood serum samples showed that the systems had good reproducibility and accuracy. The characteristics of novel ZnO and AZO thin films with GOx as a model enzyme, should prove useful for the future fabrication of inexpensive, highly sensitive, disposable electrochemical biosensors for high throughput diagnostics.

  15. Cucumber Seedling Indoleacetaldehyde Oxidase 1

    Science.gov (United States)

    Bower, Peter J.; Brown, Hugh M.; Purves, William K.

    1978-01-01

    Extracts of light-grown Cucumis sativus L. seedlings catalyzed the oxidation of indole-3-acetaldehyde to indole-3-acetic acid. No added cofactors were required. Inhibitor studies indicated that the enzyme is a metalloflavoprotein. While indole-3-aldehyde, benzaldehyde, and phenylacetaldehyde partially inhibited the oxidation of indole-3-acetaldehyde, suggesting that they may serve as alternative substrates, it is proposed that indoleacetaldehyde is the major substrate in vivo. 2,4-Dichlorophenoxyacetic acid strongly inhibited the indoleacetaldehyde oxidase activity, and it is proposed that this enzyme may be subject in vivo to feedback inhibition by indole-3-acetic acid. The enzyme was activated by brief heating or by treatment with mercaptoethanol. PMID:16660220

  16. Occurrence and Biocatalytic Potential of Carbohydrate Oxidases.

    NARCIS (Netherlands)

    Hellemond, van E.W.; Leferink, N.G.H.; Heuts, D.P.H.M.; Fraaije, M.W.; Berkel, van W.J.H.

    2006-01-01

    Carbohydrate oxidases are found in all kingdoms of life but are mostly found in fungi. Their natural role is not always clear. Usage of molecular oxygen as electron acceptor is not a logical choice when the enzyme is part of a catabolic pathway. This chapter provides an overview of the occurrence

  17. Immobilization of bilirubin oxidase on graphene oxide flakes with different negative charge density for oxygen reduction. The effect of GO charge density on enzyme coverage, electron transfer rate and current density.

    Science.gov (United States)

    Filip, Jaroslav; Andicsová-Eckstein, Anita; Vikartovská, Alica; Tkac, Jan

    2017-03-15

    Previously we showed that an effective bilirubin oxidase (BOD)-based biocathode using graphene oxide (GO) could be prepared in 2 steps: 1. electrostatic adsorption of BOD on GO; 2. electrochemical reduction of the BOD-GO composite to form a BOD-ErGO (electrochemically reduced GO) film on the electrode. In order to identify an optimal charge density of GO for BOD-ErGO composite preparation, several GO fractions differing in an average flake size and ζ-potential were prepared using centrifugation and consequently employed for BOD-ErGO biocathode preparation. A simple way to express surface charge density of these particular GO nanosheets was developed. The values obtained were then correlated with biocatalytic and electrochemical parameters of the prepared biocathodes, i.e. electrocatalytically active BOD surface coverage (Γ), heterogeneous electron transfer rate (kS) and a maximum biocatalytic current density. The highest bioelectrocatalytic current density of (597±25)μAcm(-2) and the highest Γ of (23.6±0.9)pmolcm(-2) were obtained on BOD-GO composite having the same moderate negative charge density, but the highest kS of (79.4±4.6)s(-1) was observed on BOD-GO composite having different negative charge density. This study is a solid foundation for others to consider the influence of a charge density of GO on direct bioelectrochemistry/bioelectrocatalysis of other redox enzymes applicable for construction of biosensors, bioanodes, biocathodes or biofuel cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Human pharmacology of ayahuasca: subjective and cardiovascular effects, monoamine metabolite excretion, and pharmacokinetics.

    Science.gov (United States)

    Riba, Jordi; Valle, Marta; Urbano, Gloria; Yritia, Mercedes; Morte, Adelaida; Barbanoj, Manel J

    2003-07-01

    The effects of the South American psychotropic beverage ayahuasca on subjective and cardiovascular variables and urine monoamine metabolite excretion were evaluated, together with the drug's pharmacokinetic profile, in a double-blind placebo-controlled clinical trial. This pharmacologically complex tea, commonly obtained from Banisteriopsis caapi and Psychotria viridis, combines N,N-dimethyltryptamine (DMT), an orally labile psychedelic agent showing 5-hydroxytryptamine2A agonist activity, with monoamine oxidase (MAO)-inhibiting beta-carboline alkaloids (harmine, harmaline, and tetrahydroharmine). Eighteen volunteers with prior experience in the use of psychedelics received single oral doses of encapsulated freeze-dried ayahuasca (0.6 and 0.85 mg of DMT/kg of body weight) and placebo. Ayahuasca produced significant subjective effects, peaking between 1.5 and 2 h, involving perceptual modifications and increases in ratings of positive mood and activation. Diastolic blood pressure showed a significant increase at the high dose (9 mm Hg at 75 min), whereas systolic blood pressure and heart rate were moderately and nonsignificantly increased. Cmax values for DMT after the low and high ayahuasca doses were 12.14 ng/ml and 17.44 ng/ml, respectively. Tmax (median) was observed at 1.5 h after both doses. The Tmax for DMT coincided with the peak of subjective effects. Drug administration increased urinary normetanephrine excretion, but, contrary to the typical MAO-inhibitor effect profile, deaminated monoamine metabolite levels were not decreased. This and the negligible harmine plasma levels found suggest a predominantly peripheral (gastrointestinal and liver) site of action for harmine. MAO inhibition at this level would suffice to prevent first-pass metabolism of DMT and allow its access to systemic circulation and the central nervous system.

  19. Enzyme molecules as nanomotors.

    Science.gov (United States)

    Sengupta, Samudra; Dey, Krishna K; Muddana, Hari S; Tabouillot, Tristan; Ibele, Michael E; Butler, Peter J; Sen, Ayusman

    2013-01-30

    Using fluorescence correlation spectroscopy, we show that the diffusive movements of catalase enzyme molecules increase in the presence of the substrate, hydrogen peroxide, in a concentration-dependent manner. Employing a microfluidic device to generate a substrate concentration gradient, we show that both catalase and urease enzyme molecules spread toward areas of higher substrate concentration, a form of chemotaxis at the molecular scale. Using glucose oxidase and glucose to generate a hydrogen peroxide gradient, we induce the migration of catalase toward glucose oxidase, thereby showing that chemically interconnected enzymes can be drawn together.

  20. 基于柔性衬底的ZnO葡萄糖酶电极制备及特性%Fabrication and Characteristic of ZnO Glucose Oxidase Enzyme Electrode Based on Flexible Substrate

    Institute of Scientific and Technical Information of China (English)

    李金华; 李静; 方铉; 王晓华; 魏志鹏

    2012-01-01

    通过水热法在长有ZnO籽晶层的柔性聚酰亚胺(PI)衬底上生长了整齐的ZnO纳米棒,ZnO纳米棒的晶体结构和表面形貌通过X射线衍射(XRD)、扫描电子显微镜(SEM)等进行表征.通过静电吸附方式,将葡萄糖氧化酶(GOx)固定在其表面.分别对GOx及修饰前后的ZnO纳米棒进行了紫外-可见光谱表征,发现修饰后存在ZnO的吸收峰和GOx的特征吸收峰,表明GOx固定在ZnO表面.通过对修饰样品进行傅里叶变换红外(FTIR)光谱测试发现了与GOx相关的吸收峰,这进一步表明GO×仍保持生物活性,最后在循环伏安曲线的测试中,这种在柔性衬底上制备的生物酶电极表现出非常灵敏的电流响应,为制备柔性葡萄糖生物传感器奠定了实验基础.%Well-aligned ZnO nanorods (NRs) were grown on the ZnO seed layer of a polyimide (PI)coated flexible substrate using the hydrothermal method and used as a support matrix for the immobilization of glucose oxidase (GOx).The crystal structures and surface morphologies of the so-formed ZnO nanorods were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).GOx was immobilized on the surfaces of ZnO nanorods using electrostatic adsorption.Both the GOx and modified ZnO nanorods were characterized by UV-visible spectroscopy,and the absorption peaks of ZnO and GOx can be detected.Fourier transform infrared (FTIR) spectroscopy were used to characterize the chemical structure of the glucose oxide,which still maintained its biological activity.This study provides an experiment basis for the preparation of flexible glucose biosensors owing to the flexibility of the enzyme electrode,which showed a sensitive current response when tested by cyclic voltammetry.

  1. Structure-function characterization reveals new catalytic diversity in the galactose oxidase and glyoxal oxidase family.

    Science.gov (United States)

    Yin, DeLu Tyler; Urresti, Saioa; Lafond, Mickael; Johnston, Esther M; Derikvand, Fatemeh; Ciano, Luisa; Berrin, Jean-Guy; Henrissat, Bernard; Walton, Paul H; Davies, Gideon J; Brumer, Harry

    2015-12-18

    Alcohol oxidases, including carbohydrate oxidases, have a long history of research that has generated fundamental biological understanding and biotechnological applications. Despite a long history of study, the galactose 6-oxidase/glyoxal oxidase family of mononuclear copper-radical oxidases, Auxiliary Activity Family 5 (AA5), is currently represented by only very few characterized members. Here we report the recombinant production and detailed structure-function analyses of two homologues from the phytopathogenic fungi Colletotrichum graminicola and C. gloeosporioides, CgrAlcOx and CglAlcOx, respectively, to explore the wider biocatalytic potential in AA5. EPR spectroscopy and crystallographic analysis confirm a common active-site structure vis-à-vis the archetypal galactose 6-oxidase from Fusarium graminearum. Strikingly, however, CgrAlcOx and CglAlcOx are essentially incapable of oxidizing galactose and galactosides, but instead efficiently catalyse the oxidation of diverse aliphatic alcohols. The results highlight the significant potential of prospecting the evolutionary diversity of AA5 to reveal novel enzyme specificities, thereby informing both biology and applications.

  2. Psychiatric and cognitive symptoms in Huntington's disease are modified by polymorphisms in catecholamine regulating enzyme genes

    DEFF Research Database (Denmark)

    Vinther-Jensen, T; Nielsen, T T; Budtz-Jørgensen, E;

    2016-01-01

    -described cohort of Danish HD gene-expansion carriers. We show that cognitive impairment and psychiatric symptoms in HD are modified by polymorphisms in the monoamine oxidase A (MAOA) and catechol-O-methyltransferase (COMT) genes and by the 4p16.3 B haplotype. These results support the theory of dopamine imbalance...

  3. Existence of aa3-type ubiquinol oxidase as a terminal oxidase in sulfite oxidation of Acidithiobacillus thiooxidans.

    Science.gov (United States)

    Sugio, Tsuyoshi; Hisazumi, Tomohiro; Kanao, Tadayoshi; Kamimura, Kazuo; Takeuchi, Fumiaki; Negishi, Atsunori

    2006-07-01

    It was found that Acidithiobacillus thiooxidans has sulfite:ubiquinone oxidoreductase and ubiquinol oxidase activities in the cells. Ubiquinol oxidase was purified from plasma membranes of strain NB1-3 in a nearly homogeneous state. A purified enzyme showed absorption peaks at 419 and 595 nm in the oxidized form and at 442 and 605 nm in the reduced form. Pyridine ferrohaemochrome prepared from the enzyme showed an alpha-peak characteristic of haem a at 587 nm, indicating that the enzyme contains haem a as a component. The CO difference spectrum of ubiquinol oxidase showed two peaks at 428 nm and 595 nm, and a trough at 446 nm, suggesting the existence of an aa(3)-type cytochrome in the enzyme. Ubiquinol oxidase was composed of three subunits with apparent molecular masses of 57 kDa, 34 kDa, and 23 kDa. The optimum pH and temperature for ubiquinol oxidation were pH 6.0 and 30 degrees C. The activity was completely inhibited by sodium cyanide at 1.0 mM. In contrast, the activity was inhibited weakly by antimycin A(1) and myxothiazol, which are inhibitors of mitochondrial bc(1) complex. Quinone analog 2-heptyl-4-hydoroxyquinoline N-oxide (HOQNO) strongly inhibited ubiquinol oxidase activity. Nickel and tungstate (0.1 mM), which are used as a bacteriostatic agent for A. thiooxidans-dependent concrete corrosion, inhibited ubiquinol oxidase activity 100 and 70% respectively.

  4. Cytokinin oxidase or dehydrogenase? Mechanism of cytokinin degradation in cereals

    DEFF Research Database (Denmark)

    Galuszka, P.; Frebort, I.; Sebela, M.

    2001-01-01

    wheat enzyme is a monomer 60 kDa, its N-terminal amino-acid sequence shows similarity to hypothetical cytokinin oxidase genes from Arabidopsis thaliana, but not to the enzyme from maize. N-6-isopentenyl-2-(2-hydroxyethylamino)-9-methyladenine is the best substrate from all the cytokinins tested...

  5. Direct regulation of cytochrome c oxidase by calcium ions.

    Directory of Open Access Journals (Sweden)

    Tatiana Vygodina

    Full Text Available Cytochrome c oxidase from bovine heart binds Ca(2+ reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca(2+ shifts the absorption spectrum of heme a, which allowed previously to determine the kinetics and equilibrium characteristics of the binding. However, no effect of Ca(2+ on the functional characteristics of cytochrome oxidase was revealed earlier. Here we report that Ca(2+ inhibits cytochrome oxidase activity of isolated bovine heart enzyme by 50-60% with Ki of ∼1 µM, close to Kd of calcium binding with the oxidase determined spectrophotometrically. The inhibition is observed only at low, but physiologically relevant, turnover rates of the enzyme (∼10 s(-1 or less. No inhibitory effect of Ca(2+ is observed under conventional conditions of cytochrome c oxidase activity assays (turnover number >100 s(-1 at pH 8, which may explain why the effect was not noticed earlier. The inhibition is specific for Ca(2+ and is reversed by EGTA. Na(+ ions that compete with Ca(2+ for binding with the Cation Binding Site, do not affect significantly activity of the enzyme but counteract the inhibitory effect of Ca(2+. The Ca(2+-induced inhibition of cytochrome c oxidase is observed also with the uncoupled mitochondria from several rat tissues. At the same time, calcium ions do not inhibit activity of the homologous bacterial cytochrome oxidases. Possible mechanisms of the inhibition are discussed as well as potential physiological role of Ca(2+ binding with cytochrome oxidase. Ca(2+- binding at the Cation Binding Site is proposed to inhibit proton-transfer through the exit part of the proton conducting pathway H in the mammalian oxidases.

  6. Activation of the neutrophil NADPH oxidase by Aspergillus fumigatus.

    Science.gov (United States)

    Boyle, Keith B; Stephens, Len R; Hawkins, Phillip T

    2012-12-01

    Upon infection of the respiratory system with the fungus Aspergillus fumigatus various leukoctytes, in particular neutrophils, are recruited to the lung to mount an immune response. Neutrophils respond by both phagocytosing conidia and mediating extracellular killing of germinated, invasive hyphae. Of paramount importance to an appropriate immune response is the neutrophil NADPH oxidase enzyme, which mediates the production of various reactive oxygen species (ROS). This is evidenced by the acute sensitivity of both oxidase-deficient humans and mice to invasive aspergillosis. Herein we briefly review the mechanisms and functions of oxidase activation and discuss our recent work identifying at least some of the important players in hyphal-induced oxidase activation and neutrophil function. Among these we define the phosphoinositide 3-kinase enzyme and the regulatory protein Vav to be of critical importance and allude to a kinase-independent role for Syk.

  7. Characterization of polyphenol oxidase from plants

    Institute of Scientific and Technical Information of China (English)

    LEI Dongfeng; FENG Yi; JIANG Dazong

    2004-01-01

    Polyphenol oxidase (PPO) which can mediate browning reaction is a bifunctional copper-containing enzyme encoded by plant nucleolus gene. It usually leads to excessive browning reaction which reduces the coercial profits of fruits and vegetables. In this paper, PPO genes and enzymes in plants are characterized systematically, and the latest progress is reviewed. Some clonings of PPOs genes are reported; the specific temporal and spatial expression pattern of PPOs genes is described; the model of the structure of the precursor form of catechol oxidase is introduced; the possible functions of PPOs in defending against pathogen, wounding, surrounding stress and other inducing factors are demonstrated; the induction and activation of latent PPOs in some plants is elucidated; the scheme of browning inhibition by L-cysteine is clarified; the mechanism of suicide inhibition of latent PPO and kinetic synergism are established. Furthermore, the area for future study is also discussed.

  8. Mitochondrial cytochrome c oxidase deficiency.

    Science.gov (United States)

    Rak, Malgorzata; Bénit, Paule; Chrétien, Dominique; Bouchereau, Juliette; Schiff, Manuel; El-Khoury, Riyad; Tzagoloff, Alexander; Rustin, Pierre

    2016-03-01

    As with other mitochondrial respiratory chain components, marked clinical and genetic heterogeneity is observed in patients with a cytochrome c oxidase deficiency. This constitutes a considerable diagnostic challenge and raises a number of puzzling questions. So far, pathological mutations have been reported in more than 30 genes, in both mitochondrial and nuclear DNA, affecting either structural subunits of the enzyme or proteins involved in its biogenesis. In this review, we discuss the possible causes of the discrepancy between the spectacular advances made in the identification of the molecular bases of cytochrome oxidase deficiency and the lack of any efficient treatment in diseases resulting from such deficiencies. This brings back many unsolved questions related to the frequent delay of clinical manifestation, variable course and severity, and tissue-involvement often associated with these diseases. In this context, we stress the importance of studying different models of these diseases, but also discuss the limitations encountered in most available disease models. In the future, with the possible exception of replacement therapy using genes, cells or organs, a better understanding of underlying mechanism(s) of these mitochondrial diseases is presumably required to develop efficient therapy.

  9. Discovery of Monoamine Oxidase A Inhibitors Derived from in silico Docking

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Geunhyeong; Sung, Suhyun; Lee, Younggiu; Kim, Bonggyu; Yoon, Junwie; Lee, Hyeok; Ahn, Joonghoon; Lim, Yoongho [Konkuk Univ., Seoul (Korea, Republic of); Ji, Sangyun [Rural Development Administration, Suwon (Korea, Republic of); Koh, Dongsoo [Dongduk Women' s Univ., Seoul (Korea, Republic of)

    2012-11-15

    MAOA inhibitors (MAOAIs) have been used as antidepressants for over forty years. Iproniazid was introduced in 1957, but it was withdrawn because of hepatotoxicity. Tranylcypromine was developed in the mid-1960s, withdrawn from the market because of problems related to hypertension, then reintroduced for limited usage. Many MAOAIs have been developed and used for treating atypical depression after the failure of other classes of antidepressant drugs such as selective serotonin reuptake inhibitors and tricyclic antidepressants. While iproniazid and tranylcypromine were nonselective MAOAIs, a selective MAOAI, clorgyline, was introduced in the latter half of the 1960s. Recently, more selective and safe MAOAIs, namely moclobemide, toloxatone, and tetrindol, were launched. However, their side effects and activities need further improvement. Therefore, we have made efforts to discover new MAOAIs. In conclusion, even though the number of compounds tested here is not enough for evaluation, the current result demonstrates that phenylpyrazole moiety is not necessary for showing good inhibitory effects. Because benzoflavanones have not previously been reported to act on MAOA as inhibitors, and the inhibitory effect of one of benzo-flavones, 3-(4-methoxyphenyl)-2,3-dihydro-1H-benzo[ f ] chromen-1-one used in this study is comparable to that of clorgyline which is known as MAOA inhibitor,31 our findings are meaningful.

  10. Monoamine Oxidase A: A Novel Target for Progression and Metastasis of Prostate Cancer

    Science.gov (United States)

    2013-10-01

    Target for Progression and Metastasis of Prostate Cancer PRINCIPAL INVESTIGATOR: Jean C. Shih, Ph.D. CONTRATING ORGANIZATION...aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services

  11. Linezolid, a novel oxazolidinone antibiotic: assessment of monoamine oxidase inhibition using pressor response to oral tyramine.

    Science.gov (United States)

    Antal, E J; Hendershot, P E; Batts, D H; Sheu, W P; Hopkins, N K; Donaldson, K M

    2001-05-01

    The primary objective of this study was to compare the effects of oral linezolid with moclobemide and placebo on the pressor response to oral tyramine. Secondary objectives were to determine possible mechanisms of the effect based on changes in the pharmacokinetics of tyramine and to evaluate alternative methods for quantifying the pressor effect. Subjects received linezolid (625 mg bid orally), moclobemide (150 mg tid orally), or placebo for up to 7 days. Using the oral tyramine dose producing a >30 mmHg increase in systolic blood pressure (SBP) (PD>30), a positive pressor response was defined as a PD>30 index (pretreatment/treatment ratio of PD>30) of > or = 2. There were 8/10, 11/11, and 1/10 responders with linezolid, moclobemide, and placebo, respectively. Responses returned to baseline within 2 days of drug discontinuation. The ratio of mean greatest SBP and heart rate at the time of greatest SBP (GSBP/HR) increased linearly with tyramine dose both pretreatment and during treatment with linezolid and moclobemide. During treatment, responses to tyramine when subjects took linezolid or moclobemide were significantly different from placebo. Both drugs significantly decreased tyramine oral clearance compared with placebo. Urinary excretion of catecholamines and metabolites was consistent with MAOI activity of the drugs, but results were variable. The MAOI activity of linezolid is similar to that of moclobemide, a drug used clinically without food restrictions. Restrictions to normal dietary intake of tyramine-containing foods are not warranted when taking linezolid.

  12. Monoamine Oxidase A: A Novel Target for Progression and Metastasis of Prostate Cancer

    Science.gov (United States)

    2015-12-01

    217–31. [PubMed: 22034868] 8. Gao X, Cui Y, Levenson RM, et al. In vivo cancer targeting and imaging with semiconductor quantum dots. Nat Biotechnol...16285907] 11. Wu X, Liu H, Liu J, et al. Immunofluorescent labeling of cancer marker Her2 and other cellular targets with semiconductor quantum dots...containing the reaction products was extracted, and radioactivity was determined by liquid scintillation spectroscopy. Microarray data sets. Two PCa

  13. Design and synthesis of novel chalcones as potent selective monoamine oxidase-B inhibitors.

    Science.gov (United States)

    Hammuda, Arwa; Shalaby, Raed; Rovida, Stefano; Edmondson, Dale E; Binda, Claudia; Khalil, Ashraf

    2016-05-23

    A novel series of substituted chalcones were designed and synthesized to be evaluated as selective human MAO-B inhibitors. A combination of either methylsulfonyl or trifluoromethyl substituents on the aromatic ketone moiety with a benzodioxol ring on the other end of the chalcone scaffold was investigated. The compounds were tested for their inhibitory activities on both human MAO-A and B. All compounds appeared to be selective MAO-B inhibitors with Ki values in the micromolar to submicromolar range. Molecular modeling studies have been performed to get insight into the binding mode of the synthesized compounds to human MAO-B active site.

  14. Inventory control: cytochrome c oxidase assembly regulates mitochondrial translation.

    Science.gov (United States)

    Mick, David U; Fox, Thomas D; Rehling, Peter

    2011-01-01

    Mitochondria maintain genome and translation machinery to synthesize a small subset of subunits of the oxidative phosphorylation system. To build up functional enzymes, these organellar gene products must assemble with imported subunits that are encoded in the nucleus. New findings on the early steps of cytochrome c oxidase assembly reveal how the mitochondrial translation of its core component, cytochrome c oxidase subunit 1 (Cox1), is directly coupled to the assembly of this respiratory complex.

  15. 一种来源于克劳氏芽孢杆菌的高碱性尿酸氧化酶的异源表达及重组酶性质分析%Heterologous expression of a high alkaline urate oxidase from Bacillus clausii and characterization of the recombinant enzyme

    Institute of Scientific and Technical Information of China (English)

    王一恬; 沈微; 陈献忠; 樊游; 王正祥

    2013-01-01

    以碱性蛋白酶生产菌克劳氏芽孢杆菌(Bacillus clausii)基因组DNA为模板PCR扩增获得尿酸氧化酶基因(BcU),插入原核表达载体pET28α中,构建表达载体pET-BcU,并转化大肠杆菌BL21(DE3)获得重组大肠杆菌BL21(DE3)/pET-BcU.经IPTG诱导,重组菌BL21(DE3)/pET-BcU表达出有活性的尿酸氧化酶,含空质粒的重组菌在同样条件下没有酶活.酶学性质分析显示,重组酶最适pH值为9.0,在pH值9.0~11范围内酶活几乎不变,是一种高碱性尿酸氧化酶.%The BcU gene encoding urate oxidase was amplified by PCR with genome DNA of Bacillus clausii as template. The gene BcU was cloned into pET28α resulting in the recombinant plasmid pET-BcU. The recombiant plasmid was transformed into Escherichia coli BL21(DE3). Induced with IPTG, the recombinant strain BL21 ( DE3 )/pET-BcU expressed active urate oxidase, while the control BL21 ( DE3 )/pET did not. The optimum pH for recombinant enzyme was 9. 0 and the enzymatic activity showed almost no difference between pH 9. 0 ~ 11. The recombinant enzyme is a kind of high alkaline urate oxidase.

  16. Monoamine transporters: insights from molecular dynamics simulations

    Science.gov (United States)

    Grouleff, Julie; Ladefoged, Lucy Kate; Koldsø, Heidi; Schiøtt, Birgit

    2015-01-01

    The human monoamine transporters (MATs) facilitate the reuptake of the neurotransmitters serotonin, dopamine, and norepinephrine from the synaptic cleft. Imbalance in monoaminergic neurotransmission is linked to various diseases including major depression, attention deficit hyperactivity disorder, schizophrenia, and Parkinson’s disease. Inhibition of the MATs is thus an important strategy for treatment of such diseases. The MATs are sodium-coupled transport proteins belonging to the neurotransmitter/Na+ symporter (NSS) family, and the publication of the first high-resolution structure of a NSS family member, the bacterial leucine transporter LeuT, in 2005, proved to be a major stepping stone for understanding this family of transporters. Structural data allows for the use of computational methods to study the MATs, which in turn has led to a number of important discoveries. The process of substrate translocation across the membrane is an intrinsically dynamic process. Molecular dynamics simulations, which can provide atomistic details of molecular motion on ns to ms timescales, are therefore well-suited for studying transport processes. In this review, we outline how molecular dynamics simulations have provided insight into the large scale motions associated with transport of the neurotransmitters, as well as the presence of external and internal gates, the coupling between ion and substrate transport, and differences in the conformational changes induced by substrates and inhibitors. PMID:26528185

  17. NADH/NADPH Oxidase and Vascular Function.

    Science.gov (United States)

    Griendling, K K; Ushio-Fukai, M

    1997-11-01

    The vascular NADH/NADPH oxidase has been shown to be the major source of superoxide in the vessel wall. Recent work has provided insight into its structure and activity in vascular cells. This enzyme is involved in both vascular smooth muscle hypertrophy and in some forms of impaired endothelium-dependent relaxation. Because oxidative stress in general participates in the pathogenesis of hypertension and atherosclerosis, the enzymes that produce reactive oxygen species may be important determinants of the course of vascular disease. (Trends Cardiovasc Med 1997;7:301-307). © 1997, Elsevier Science Inc.

  18. Characterization of wheat germin (oxalate oxidase) expressed by Pichia pastoris

    Science.gov (United States)

    Pan, Heng-Yen; Whittaker, Mei M.; Bouveret, Romaric; Berna, Anne; Bernier, François; Whittaker, James W.

    2007-01-01

    High-level secretory expression of wheat (Triticum aestivum) germin/oxalate oxidase was achieved in Pichia pastoris fermentation cultures as an α-mating factor signal peptide fusion, based on the native wheat cDNA coding sequence. The oxalate oxidase activity of the recombinant enzyme is substantially increased (7-fold) by treatment with sodium periodate, followed by ascorbate reduction. Using these methods, approximately 1 g (4×104 U) of purified, activated enzyme was obtained following eight days of induction of a high density Pichia fermentation culture, demonstrating suitability for large-scale production of oxalate oxidase for biotechnological applications. Characterization of the recombinant protein shows that it is glycosylated, with N-linked glycan attached at Asn47. For potential biomedical applications, a nonglycosylated (S49A) variant was also prepared which retains essentially full enzyme activity, but exhibits altered protein-protein interactions. PMID:17399681

  19. Glucose oxidase immobilization onto carbon nanotube networking

    CERN Document Server

    Karachevtsev, V A; Zarudnev, E S; Karachevtsev, M V; Leontiev, V S; Linnik, A S; Lytvyn, O S; Plokhotnichenko, A M; Stepanian, S G

    2012-01-01

    When elaborating the biosensor based on single-walled carbon nanotubes (SWNTs), it is necessary to solve such an important problem as the immobilization of a target biomolecule on the nanotube surface. In this work, the enzyme (glucose oxidase (GOX)) was immobilized on the surface of a nanotube network, which was created by the deposition of nanotubes from their solution in 1,2-dichlorobenzene by the spray method. 1-Pyrenebutanoic acid succinimide ester (PSE) was used to form the molecular interface, the bifunctional molecule of which provides the covalent binding with the enzyme shell, and its other part (pyrene) is adsorbed onto the nanotube surface. First, the usage of such a molecular interface leaves out the direct adsorption of the enzyme (in this case, its activity decreases) onto the nanotube surface, and, second, it ensures the enzyme localization near the nanotube. The comparison of the resonance Raman (RR) spectrum of pristine nanotubes with their spectrum in the PSE environment evidences the creat...

  20. Characterization of Glucose Oxidase from Penicillium notatum

    Directory of Open Access Journals (Sweden)

    Nabeela Saleem

    2009-01-01

    Full Text Available In the present study glucose oxidase (GOD has been isolated from a culture filtrate of Penicillium notatum. The enzyme was purified by ammonium sulphate precipitation, diethylaminoethyl (DEAE cellulose ion-exchange chromatography and Sephadex gel filtration. This protocol gave 16.47-fold purification and 25 % recovery of the enzyme. The optimum pH and temperature for the activity were 5.4 and 45 °C, respectively. The Km and vmax values for the enzyme were 10.5 mM and 456 U/mg, respectively. A detailed kinetic study of thermal inactivation was carried out. Both enthalpy of activation (ΔH* and entropy of activation (ΔS* decreased at higher temperatures. Moreover, free energy of denaturation (ΔG* increased at higher temperature, making the enzyme thermally stable. A possible explanation for the thermal inactivation of GOD at higher temperatures is also discussed.

  1. Structural insights into electron transfer in caa 3-type cytochrome oxidase

    OpenAIRE

    Lyons, Joseph A.; Aragão, David; Slattery, Orla; Pisliakov, Andrei V.; Soulimane, Tewfik; Caffrey, Martin

    2012-01-01

    Summary Paragraph Cytochrome c oxidase is a member of the heme copper oxidase superfamily (HCO) 1 . HCOs function as the terminal enzymes in the respiratory chain of mitochondria and aerobic prokaryotes, coupling molecular oxygen reduction to transmembrane proton pumping. Integral to the enzyme’s function is the transfer of electrons from cytochrome c to the oxidase via a transient association of the two proteins. Electron entry and exit are proposed to occur from the same site on cytochrome ...

  2. Peripheral and CNS effects of the pineal gland: target enzymes common to tissues and species

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, L.C.

    1976-01-01

    Specific endocrine rhythms are affected by alterations in trophic hormone secretion by the hypothalamus-pituitary complex, direct effects on biochemical transformations within target organs, or by alterations in metabolism and excretion of hormones by the liver. Target enzymes common to endocrine organ for melatonin and arginine vasotocin (AVT) are 5..cap alpha..-reductase, monoamine oxidase (MAO), and smooth muscle enzymes. Melatonin selectively inhibited 17 ..beta.. ol-dehydrogenase acivity and 5..cap alpha..-reductase activity while 17..beta.. ol-dehydrogenase was stimulated by serotonin (5-HT). Other steroid biotransformations were inhibited by both 5-HT and melatonin. Evidence from the pancreas and insulin secretion, liver and glucuronosyl transferase activity, and hypothalamic and pituitary studies indicate that melatonin mediated some of its effects on these organs through MAO activity and 5-HT levels. There were some species and tissue differences with respect to the effects of melatonin and AVT on MAO activity and steroid biotransformations. Melatonin stimulated steroid biotransformations in the duck, while MAO activity and 5..cap alpha..-reductase activity in the hamster responded differently to melatonin than did similar preparations from the rat.

  3. Bioelectrochemical Response and Kinetics of Choline Oxidase Entrapped in Polyaniline-Polyacrylonitrile Composite Film

    Institute of Scientific and Technical Information of China (English)

    XUE,Huai-Guo(薛怀国); SHEN,Zhi-Quan(沈之荃)

    2002-01-01

    A novel choline oxidase electrode was constructed by entrapping choline oxidase into polyaniline-polyacrylonitrile composite film. The enzyme film was prepared by in situ electropolymerization of aniline into porous polyacrylonitrile-coated platinum electrode in the presence of choline oxidase. The enzyme electrode exhibited sensitive and stable electrochemical response to choline. The kinetics analysis showed that the mass transport is partially rate-limiting. The influences of pH, applied potential and temperature on the response of the enzyme electrode were also described.

  4. Long-term exposure to xenoestrogens alters some brain monoamines and both serum thyroid hormones and cortisol levels in adult male rats

    Directory of Open Access Journals (Sweden)

    Nashwa M. Saied

    2014-10-01

    Full Text Available The present study was designed to examine the effect of long-term treatment with the phytoestrogen soy isoflavone [(SIF; 43 mg/kg body weight/day] and/or the plastics component bisphenol-A [(BPA; 3 mg/kg body weight/day] on some monoamines in the forebrain and both serum thyroid hormones and cortisol levels of adult rats. Significant increases in serotonin (5-HT and norepinephrine (NE level, and significant decreases in 5-hydroxyindoleacetic acid (5-HIAA level and 5-HIAA/5-HT ratio, were observed after treatment with SIF or BPA. Level of dopamine (DA was increased in SIF-treated group and decreased in BPA-treated group. Activity of monoamine oxidase (MAO was decreased in all treated groups. The level of serum thyroid hormones (fT3 and fT4 was increased after treatment with SIF and decreased after exposure to BPA, while cortisol level was increased in all treated groups. It may be concluded that long-term exposure to SIF or BPA disrupts monoamine levels in the forebrain of adult rats through alteration in the metabolic pathways of amines and disorders of thyroid hormones and cortisol levels.

  5. Treatment with the MAO-A inhibitor clorgyline elevates monoamine neurotransmitter levels and improves affective phenotypes in a mouse model of Huntington disease.

    Science.gov (United States)

    Garcia-Miralles, Marta; Ooi, Jolene; Ferrari Bardile, Costanza; Tan, Liang Juin; George, Maya; Drum, Chester L; Lin, Rachel Yanping; Hayden, Michael R; Pouladi, Mahmoud A

    2016-04-01

    Abnormal monoamine oxidase A and B (MAO-A/B) activity and an imbalance in monoamine neurotransmitters have been suggested to underlie the pathobiology of depression, a major psychiatric symptom observed in patients with neurodegenerative diseases, such as Huntington disease (HD). Increased MAO-A/B activity has been observed in brain tissue from patients with HD and in human and rodent HD neural cells. Using the YAC128 mouse model of HD, we studied the effect of an irreversible MAO-A inhibitor, clorgyline, on the levels of select monoamine neurotransmitters associated with affective function. We observed a decrease in striatal levels of the MAO-A/B substrates, dopamine and norepinephrine, in YAC128 HD mice compared with wild-type mice, which was accompanied by increased anxiety- and depressive-like behaviour at five months of age. Treatment for 26 days with clorgyline restored dopamine, serotonin, and norepinephrine neurotransmitter levels in the striatum and reduced anxiety- and depressive-like behaviour in YAC128 HD mice. This study supports a potential therapeutic use for MAO-A inhibitors in the treatment of depression and anxiety in patients with HD.

  6. Antidepressant like effects of hydrolysable tannins of Terminalia catappa leaf extract via modulation of hippocampal plasticity and regulation of monoamine neurotransmitters subjected to chronic mild stress (CMS).

    Science.gov (United States)

    Chandrasekhar, Y; Ramya, E M; Navya, K; Phani Kumar, G; Anilakumar, K R

    2017-02-01

    Terminalia catappa L. belonging to Combretaceae family is a folk medicine, known for its multiple pharmacological properties, but the neuro-modulatory effect of TC against chronic mild stress was seldom explored. The present study was designed to elucidate potential antidepressant-like effect of Terminalia cattapa (leaf) hydro-alcoholic extract (TC) by using CMS model for a period of 7 weeks. Identification of hydrolysable tannins was done by using LC-MS. After the CMS exposure, mice groups were administered with imipramine (IMP, 10mg/kg, i.p.) and TC (25, 50 and 100mg/kg of TC, p.o.). Behavioural paradigms used for the study included forced swimming test (FST), tail suspension test (TST) and sucrose preference test (SPT). After behavioural tests, monoamine neurotransmitter, cortisol, AchE, oxidative stress levels and mRNA expression studies relevant to depression were assessed. TC supplementation significantly reversed CMS induced immobility time in FST and other behavioural paradigms. Moreover, TC administration significantly restored CMS induced changes in concentrations of hippocampal neurotransmitters (5-HT, DA and NE) as well as levels of acetyl cholinesterase, cortisol, monoamine oxidases (MAO-A, MAO-B), BDNF, CREB, and p-CREB. It suggests that TC supplementation could supress stress induced depression by regulating monoamine neurotransmitters, CREB, BDNF, cortisol, AchE level as well as by amelioration of oxidative stress. Hence TC can be used as a complementary medicine against depression-like disorder.

  7. On the structure and function of the phytoene desaturase CRTI from Pantoea ananatis, a membrane-peripheral and FAD-dependent oxidase/isomerase.

    Directory of Open Access Journals (Sweden)

    Patrick Schaub

    Full Text Available CRTI-type phytoene desaturases prevailing in bacteria and fungi can form lycopene directly from phytoene while plants employ two distinct desaturases and two cis-tans isomerases for the same purpose. This property renders CRTI a valuable gene to engineer provitamin A-formation to help combat vitamin A malnutrition, such as with Golden Rice. To understand the biochemical processes involved, recombinant CRTI was produced and obtained in homogeneous form that shows high enzymatic activity with the lipophilic substrate phytoene contained in phosphatidyl-choline (PC liposome membranes. The first crystal structure of apo-CRTI reveals that CRTI belongs to the flavoprotein superfamily comprising protoporphyrinogen IX oxidoreductase and monoamine oxidase. CRTI is a membrane-peripheral oxidoreductase which utilizes FAD as the sole redox-active cofactor. Oxygen, replaceable by quinones in its absence, is needed as the terminal electron acceptor. FAD, besides its catalytic role also displays a structural function by enabling the formation of enzymatically active CRTI membrane associates. Under anaerobic conditions the enzyme can act as a carotene cis-trans isomerase. In silico-docking experiments yielded information on substrate binding sites, potential catalytic residues and is in favor of single half-site recognition of the symmetrical C(40 hydrocarbon substrate.

  8. Xanthine oxidase biosensor for monitoring meat spoilage

    Science.gov (United States)

    Vanegas, D. C.; Gomes, C.; McLamore, E. S.

    2014-05-01

    In this study, we have designed an electrochemical biosensor for real-time detection of specific biomarkers of bacterial metabolism related to meat spoilage (hypoxanthine and xanthine). The selective biosensor was developed by assembling a `sandwich' of nanomaterials and enzymes on a platinum-iridium electrode (1.6 mm tip diameter). The materials deposited on the sensor tip include amorphous platinum nanoclusters (i.e. Pt black), reduced graphene oxide, nanoceria, and xanthine oxidase. Xanthine oxidase was encapsulated in laponite hydrogel and used for the biorecognition of hypoxanthine and xanthine (two molecules involved in the rotting of meat by spoilage microorganisms). The developed biosensor demonstrated good electrochemical performance toward xanthine with sensitivity of 2.14 +/- 1.48 μA/mM, response time of 5.2 +/- 1.5 sec, lower detection limit of 150 +/- 39 nM, and retained at least 88% of its activity after 7 days of continuous use.

  9. Mechanism of Flavoprotein l-6-Hydroxynicotine Oxidase: pH and Solvent Isotope Effects and Identification of Key Active Site Residues.

    Science.gov (United States)

    Fitzpatrick, Paul F; Chadegani, Fatemeh; Zhang, Shengnan; Dougherty, Vi

    2017-02-14

    The flavoenzyme l-6-hydroxynicotine oxidase is a member of the monoamine oxidase family that catalyzes the oxidation of (S)-6-hydroxynicotine to 6-hydroxypseudooxynicotine during microbial catabolism of nicotine. While the enzyme has long been understood to catalyze oxidation of the carbon-carbon bond, it has recently been shown to catalyze oxidation of a carbon-nitrogen bond [Fitzpatrick, P. F., et al. (2016) Biochemistry 55, 697-703]. The effects of pH and mutagenesis of active site residues have now been utilized to study the mechanism and roles of active site residues. Asn166 and Tyr311 bind the substrate, while Lys287 forms a water-mediated hydrogen bond with flavin N5. The N166A and Y311F mutations result in ∼30- and ∼4-fold decreases in kcat/Km and kred for (S)-6-hydroxynicotine, respectively, with larger effects on the kcat/Km value for (S)-6-hydroxynornicotine. The K287M mutation results in ∼10-fold decreases in these parameters and a 6000-fold decrease in the kcat/Km value for oxygen. The shapes of the pH profiles are not altered by the N166A and Y311F mutations. There is no solvent isotope effect on the kcat/Km value for amines. The results are consistent with a model in which both the charged and neutral forms of the amine can bind, with the former rapidly losing a proton to a hydrogen bond network of water and amino acids in the active site prior to the transfer of hydride to the flavin.

  10. The Oxidation of Thiols by Flavoprotein Oxidases : a Biocatalytic Route to Reactive Thiocarbonyls

    NARCIS (Netherlands)

    Ewing, Tom A.; Dijkman, Willem P.; Vervoort, Jacques M.; Fraaije, Marco W.; van Berkel, Willem J. H.

    2014-01-01

    Flavoprotein oxidases are a diverse class of biocatalysts, most of which catalyze the oxidation of C-O, C-N, or C-C bonds. Flavoprotein oxidases that are known to catalyze the oxidation of C-S bonds are rare, being limited to enzymes that catalyze the oxidative cleavage of thioethers. Herein, we rep

  11. The Oxidation of Thiols by Flavoprotein Oxidases: a Biocatalytic Route to Reactive Thiocarbonyls.

    NARCIS (Netherlands)

    Ewing, T.A.; Dijkman, W.P.; Vervoort, J.J.M.; Fraaije, M.W.; Berkel, van W.J.H.

    2014-01-01

    Flavoprotein oxidases are a diverse class of biocatalysts, most of which catalyze the oxidation of C[BOND]O, C[BOND]N, or C[BOND]C bonds. Flavoprotein oxidases that are known to catalyze the oxidation of C[BOND]S bonds are rare, being limited to enzymes that catalyze the oxidative cleavage of thioet

  12. Analysis of cellulase and polyphenol oxidase production by southern pine beetle associated fungi

    Science.gov (United States)

    Abduvali Valiev; Zumrut B. Ogel; Dier D. Klepzig

    2009-01-01

    In this study, the production of extracellular enzymes by fungi associated with southern pine beetle was investigated for the first time. Cellulase and polyphenol oxidase production were analyzed for three beetle associated fungi. Only the mutualistic symbiont Entomocorticium sp. A was found to produce cellulases and polyphenol oxidase....

  13. Structural analysis of the catalytic mechanism and stereo selectivity in Streptomyces coelicolor alditol oxidase

    NARCIS (Netherlands)

    Forneris, Federico; Heuts, Dominic P. H. M.; Delvecchio, Manuela; Rovida, Stefano; Fraaije, Marco W.; Mattevi, Andrea

    2008-01-01

    Alditol oxidase (AldO) from Streptomyces coelicolor A3(2) is a soluble monomeric flavin-dependent oxidase that performs selective oxidation of the terminal primary hydroxyl group of several alditols. Here, we report the crystal structure of the recombinant enzyme in its native state and in complex w

  14. Spectral and catalytic properties of aryl-alcohol oxidase, a fungal flavoenzyme acting on polyunsaturated alcohols

    NARCIS (Netherlands)

    Ferreira, P.; Medina, M.; Guillén, F.; Martínez, M.J.; Berkel, van W.J.H.; Martínez, A.T.

    2005-01-01

    Spectral and catalytic properties of the flavoenzyme AAO (aryl-alcohol oxidase) from Pleurotus eryngii were investigated using recombinant enzyme. Unlike most flavoprotein oxidases, AAO does not thermodynamically stabilize a flavin semiquinone radical and forms no sulphite adduct. AAO catalyses the

  15. Biodegradation of phenolic compounds with oxidases from sorghum and non-defined mixed bacterium media

    Energy Technology Data Exchange (ETDEWEB)

    Obame, C. E. L.; Savadogo, P. W.; Mamoudou, D. H.; Dembele, R. H.; Traore, A. S.

    2009-07-01

    The biodegradation of the phenolic compounds is performed using oxidative enzymes, e. g. polyphenol oxidases (PPOs) and peroxidases (POXs). These oxidases displaying a wide spectrum for the oxidation of phenolic compounds were isolated either from sorghum or mixed bacteria. Spectrophotometric methods were used to assess the monophenolase and diphenolase activities of PPOs as well as the hydrogen-dependant oxidation of POXs. (Author)

  16. Enzyme Analysis to Determine Glucose Content

    Science.gov (United States)

    Carpenter, Charles; Ward, Robert E.

    Enzyme analysis is used for many purposes in food science and technology. Enzyme activity is used to indicate adequate processing, to assess enzyme preparations, and to measure constituents of foods that are enzyme substrates. In this experiment, the glucose content of corn syrup solids is determined using the enzymes, glucose oxidase and peroxidase. Glucose oxidase catalyzes the oxidation of glucose to form hydrogen peroxide (H2O2), which then reacts with a dye in the presence of peroxidase to give a stable colored product.

  17. Stimulation of vesicular monoamine transporter 2 activity by DJ-1 in SH-SY5Y cells

    OpenAIRE

    Ishikawa, Shizuma; Tanaka, Yuki; Takahashi-Niki, Kazuko; Niki, Takeshi; Ariga, Hiroyoshi; Iguchi-Ariga, Sanae M. M.

    2012-01-01

    Loss-of-functional mutation in the DJ-1 gene causes a subset of familial Parkinson's disease. The mechanism underlying DJ-1-related selective vulnerability in the dopaminergic pathway is, however, not known. Dopamine is synthesized by two enzymes and then packed into synaptic vesicles by vesicular monoamine transporter 2 (VMAT2). In this study, we found that knockdown of DJ-1 expression reduced the levels of mRNA and protein of VMAT2, resulting in reduced VMAT2 activity. Co-immunoprecipitatio...

  18. In vivo oxalate degradation by liposome encapsulated oxalate oxidase in rat model of hyperoxaluria

    Directory of Open Access Journals (Sweden)

    Tulika Dahiya

    2013-01-01

    Interpretation & conclusions: EMA-oxalate oxidase encapsulated liposome caused oxalate degradation in experimental hyperoxaluria indicating that the enzyme could be used as a therapeutic agent in hyperoxaluria leading to urinary stones.

  19. Inhibitory activity of xanthine oxidase by fractions Crateva adansonii

    Directory of Open Access Journals (Sweden)

    A Abdullahi

    2012-01-01

    Conclusions: Enzyme inhibition mechanism indicated that the mode of inhibition was of a mixed type. Our findings suggest that the therapeutic use of these plants may be due to the observed Xanthine oxidase inhibition, thereby supporting their use in traditional folk medicine against inflammatory-related diseases, in particular, gout.

  20. Semicarbazide-sensitive amine oxidase (SSAO): from cell to circulation

    NARCIS (Netherlands)

    F. Boomsma (Frans); H. Hut; U. Bagghoe; A.H. van den Meiracker (Anton)

    2005-01-01

    textabstractSemicarbazide-sensitive amine oxidase (SSAO) is a multi-functional enzyme widely present in nature. It converts primary amines into their corresponding aldehydes, while generating H(2)O(2) and NH(3). In mammals, SSAO circulates in plasma, while a membrane-bound form (of

  1. Semicarbazide-sensitive amine oxidase (SSAO): from cell to circulation

    NARCIS (Netherlands)

    F. Boomsma (Frans); H. Hut; U. Bagghoe; A.H. van den Meiracker (Anton)

    2005-01-01

    textabstractSemicarbazide-sensitive amine oxidase (SSAO) is a multi-functional enzyme widely present in nature. It converts primary amines into their corresponding aldehydes, while generating H(2)O(2) and NH(3). In mammals, SSAO circulates in plasma, while a membrane-bound form

  2. Subcellular localization of vanillyl-alcohol oxidase in Penicillium simplicissimum

    NARCIS (Netherlands)

    Fraaije, MW; Sjollema, KA; Veenhuis, M; van Berkel, WJH; Berkel, Willem J.H. van

    1998-01-01

    Growth of Penicillium simplicissimum on anisyl alcohol, veratryl alcohol or 3-(methoxymethyl)phenol, is associated with the synthesis of relatively large amounts of the hydrogen peroxide producing flavoprotein vanillyl-alcohol oxidase (VAO), Immunocytochemistry revealed that the enzyme has a dual lo

  3. ADP competes with FAD binding in putrescine oxidase

    NARCIS (Netherlands)

    van Hellemond, Erik W.; Mazon, Hortense; Heck, Albert J.; van den Heuvel, Robert H. H.; Heuts, Dominic P. H. M.; Janssen, Dick B.; Fraaije, Marco W.

    2008-01-01

    Putrescine oxidase from Rhodococcus erythropolis NCIMB 11540 (PuORh) is a soluble homodimeric flavoprotein of 100 kDa, which catalyzes the oxidative deamination of putrescine and some other aliphatic amines. The initial characterization of PuORh uncovered an intriguing feature: the enzyme appeared t

  4. Cloning and expression of DNA encoding a ripening from a polypeptide having sulfhydryl oxidase activity.

    NARCIS (Netherlands)

    Maat, J.; Musters, W.; Stam, H.; Schaap, P.J.; Vondervoort, van de P.J.J.; Visser, J.; Verbakel, J.M.A.

    1993-01-01

    The invention relates to recombinant DNA technology for the production of an enzyme having sulfhydryl oxidase ("SOX") activity. This SOX-enzyme can be used where the oxidation of free sulfhydryl groups (thio compounds) to the corresponding disulfides is desirable. SOX enzyme may be used for treatmen

  5. A predicted structure of the cytochrome c oxidase from Burkholderia pseudomallei

    OpenAIRE

    Mohd. Raih,Mohd. Firdaus; Sailan,Ahmad Tarmidi; Zamrod,Zulkeflie; Embi,Mohd. Noor; Mohamed, Rahmah

    2003-01-01

    Cytochrome c oxidase, the terminal enzyme of the respiratory chains of mitochondria and aerobic bacteria, catalyzes electron transfer from cytochrome c to molecular oxygen. The enzyme belongs to the haem-copper-containing oxidases superfamily. A recombinant plasmid carrying a 2.0 kb insert from a Burkholderia pseudomallei genomic library was subjected to automated DNA sequencing utilizing a primer walking strategy. Analysis of the 2002 bp insert revealed a 1536 bp open reading frame predicted...

  6. The role of lysyl oxidase in SRC-dependent proliferation and metastasis of colorectal cancer

    DEFF Research Database (Denmark)

    Baker, Ann-Marie; Cox, Thomas Robert; Bird, Demelza;

    2011-01-01

    Emerging evidence implicates lysyl oxidase (LOX), an extracellular matrix-modifying enzyme, in promoting metastasis of solid tumors. We investigated whether LOX plays an important role in the metastasis of colorectal cancer (CRC).......Emerging evidence implicates lysyl oxidase (LOX), an extracellular matrix-modifying enzyme, in promoting metastasis of solid tumors. We investigated whether LOX plays an important role in the metastasis of colorectal cancer (CRC)....

  7. PHARMACOLOGICAL EFFECTS OF SNAKE VENOM L- AMINO ACID OXIDASES

    OpenAIRE

    Joseph Baby; Rajan Sheeja S; M.V Jeevitha; S.U Ajisha

    2011-01-01

    L-Amino acid oxidases are flavoenzymes which catalyze the stereospecific oxidative deamination of an L-amino acid substrate to a corresponding a-ketoacid with hydrogen peroxide and ammonia production. These enzymes, which are widely distributed in many different organisms, exhibit a marked affinity for hydrophobic amino acids, including phenylalanine, tryptophan, tyrosine, and leucine. Snake venom LAAO induces platelet aggregation and cytotoxicity in various cancer cell lines. The enzyme has ...

  8. Cyanobacterial lactate oxidases serve as essential partners of N2-fixation and evolved to photorespiratory glycolate oxidases in plants

    NARCIS (Netherlands)

    Hackenberg, C.; Kern, R.; Hüge, J.; Stal, L.J.; Tsuji, Y.; Kopka, J.; Shiraiwa, Y.; Bauwe, H.; Hagemann, M.

    2011-01-01

    Glycolate oxidase (GOX) is an essential enzyme involved in photorespiratory metabolism in plants. In cyanobacteria and green algae, the corresponding reaction is catalyzed by glycolate dehydrogenases (GlcD). The genomes of N2-fixing cyanobacteria, such as Nostoc PCC 7120 and green algae, appear to h

  9. Cyanobacterial lactate oxidases serve as essential partners in N2-fixation and evolved into photorespiratory glycolate oxidases in plants.

    NARCIS (Netherlands)

    Hackenberg, C.; Kern, R.; Hüge, J; Stal, L.J.; Tsuji, Y.; Kopka, J.; Shiraiwa, Y.; Bauwe, H.; Hagemann, M.

    2011-01-01

    Glycolate oxidase (GOX) is an essential enzyme involved in photorespiratory metabolism in plants. In cyanobacteria and green algae, the corresponding reaction is catalyzed by glycolate dehydrogenases (GlcD). The genomes of N2-fixing cyanobacteria, such as Nostoc PCC 7120 and green algae, appear to

  10. Cyanobacterial lactate oxidases serve as essential partners of N2-fixation and evolved to photorespiratory glycolate oxidases in plants

    NARCIS (Netherlands)

    Hackenberg, C.; Kern, R.; Hüge, J.; Stal, L.J.; Tsuji, Y.; Kopka, J.; Shiraiwa, Y.; Bauwe, H.; Hagemann, M.

    2011-01-01

    Glycolate oxidase (GOX) is an essential enzyme involved in photorespiratory metabolism in plants. In cyanobacteria and green algae, the corresponding reaction is catalyzed by glycolate dehydrogenases (GlcD). The genomes of N2-fixing cyanobacteria, such as Nostoc PCC 7120 and green algae, appear to

  11. Cyanobacterial lactate oxidases serve as essential partners in N2-fixation and evolved into photorespiratory glycolate oxidases in plants.

    NARCIS (Netherlands)

    Hackenberg, C.; Kern, R.; Hüge, J; Stal, L.J.; Tsuji, Y.; Kopka, J.; Shiraiwa, Y.; Bauwe, H.; Hagemann, M.

    2011-01-01

    Glycolate oxidase (GOX) is an essential enzyme involved in photorespiratory metabolism in plants. In cyanobacteria and green algae, the corresponding reaction is catalyzed by glycolate dehydrogenases (GlcD). The genomes of N2-fixing cyanobacteria, such as Nostoc PCC 7120 and green algae, appear to h

  12. Cytochemical Studies on the Localization of Methanol Oxidase and Other Oxidases in Peroxisomes of Methanol-Grown Hansenula polyrnorpha

    NARCIS (Netherlands)

    Veenhuis, M.; Dijken, J.P. van; Harder, W.

    1976-01-01

    The localization of methanol oxidase activity in cells of methanol-limited chemostat cultures of the yeast Hansenula polymorpha has been studied with different cytochemical staining techniques. The methods were based on enzymatic or chemical trapping of the hydrogen peroxide produced by the enzyme d

  13. Cox26 is a novel stoichiometric subunit of the yeast cytochrome c oxidase.

    Science.gov (United States)

    Levchenko, Maria; Wuttke, Jan-Moritz; Römpler, Katharina; Schmidt, Bernhard; Neifer, Klaus; Juris, Lisa; Wissel, Mirjam; Rehling, Peter; Deckers, Markus

    2016-07-01

    The cytochrome c oxidase (COX) is the terminal enzyme of the respiratory chain. The complex accepts electrons from cytochrome c and passes them onto molecular oxygen. This process contributes to energy capture in the form of a membrane potential across the inner membrane. The enzyme complex assembles in a stepwise process from the three mitochondria-encoded core subunits Cox1, Cox2 and Cox3, which associate with nuclear-encoded subunits and cofactors. In the yeast Saccharomyces cerevisiae, the cytochrome c oxidase associates with the bc1-complex into supercomplexes, allowing efficient energy transduction. Here we report on Cox26 as a protein found in respiratory chain supercomplexes containing cytochrome c oxidase. Our analyses reveal Cox26 as a novel stoichiometric structural subunit of the cytochrome c oxidase. A loss of Cox26 affects cytochrome c oxidase activity and respirasome organization.

  14. Cation binding site of cytochrome c oxidase: progress report.

    Science.gov (United States)

    Vygodina, Tatiana V; Kirichenko, Anna; Konstantinov, Alexander A

    2014-07-01

    Cytochrome c oxidase from bovine heart binds Ca(2+) reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca(2+) shifts the absorption spectrum of heme a, which allowed earlier the determination of the kinetic and equilibrium characteristics of the binding, and, as shown recently, the binding of calcium to the site inhibits cytochrome oxidase activity at low turnover rates of the enzyme [Vygodina, Т., Kirichenko, A., Konstantinov, A.A (2013). Direct Regulation of Cytochrome c Oxidase by Calcium Ions. PloS ONE 8, e74436]. This paper summarizes further progress in the studies of the Cation Binding Site in this group presenting the results to be reported at 18th EBEC Meeting in Lisbon, 2014. The paper revises specificity of the bovine oxidase Cation Binding Site for different cations, describes dependence of the Ca(2+)-induced inhibition on turnover rate of the enzyme and reports very high affinity binding of calcium with the "slow" form of cytochrome oxidase. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference. Guest Editors: Manuela Pereira and Miguel Teixeira.

  15. Phenolic compounds and related enzymes as determinants of sorghum for food use

    NARCIS (Netherlands)

    Dicko, M.H.; Gruppen, H.; Traore, A.S.; Voragen, A.G.J.; Berkel, van W.J.H.

    2006-01-01

    Phenolic compounds and related enzymes such as phenol biosynthesizing enzymes (phenylalanine ammonia lyase) and phenol catabolizing enzymes (polyphenol oxidase and peroxidase) are determinants for sorghum utilization as human food because they influence product properties during and after sorghum pr

  16. Structures and functions of insect arylalkylamine N-acetyltransferase (iaaNAT; a key enzyme for physiological and behavioral switch in arthropods

    Directory of Open Access Journals (Sweden)

    Susumu eHiragaki

    2015-04-01

    Full Text Available The evolution of N-acetyltransfeases (NATs seems complex. Vertebrate arylalkylamine N-acetyltransferase (aaNAT has been extensively studied since it Leads to the synthesis of melatonin, a multifunctional neurohormone prevalent in photoreceptor cells, and is known as as a chemical token of the night. Melatonin also serves as a scavenger for reactive oxygen species. This is also true with invertebrates. NAT therefore has distinct functional implications in circadian function, as timezymes (aaNAT, and also xenobiotic reactions (arylamine NAT or simply NAT. NATs belong to a broader enzyme group, the GCN5-related N-acetyltransferase superfamily. Due to low sequence homology and a seemingly fast rate of structural differentiation, the nomenclature for NATs can be confusing. The advent of bioinformatics, however, has helped to classify this group of enzymes; vertebrates have two distinct subgroups, the timezyme type and the xenobiotic type, which has a wider substrate range including imidazolamine, pharmacological drugs, environmental toxicants and even histone. Insect aaNAT (iaaNAT form their own clade in the phylogeny, distinct from vertebrate aaNATs. Arthropods are unique, since the phylum has exoskeleton in which quinones derived from N-acetylated monoamines function in coupling chitin and arthropodins. Monoamine oxidase (MAO activity is limited in insects, but NAT-mediated degradation prevails. However, unexpectedly iaaNAT occurs not only among arthropods but also among basal deuterostomia, and is therefore more apomorphic. Our analyses illustrate that iaaNATs has unique physiological roles but at the same time it plays a role in a timezyme function, at least in photoperiodism. Photoperiodism has been considered as a function of circadian system but the detailed molecular mechanism is not well understood. We propose a molecular hypothesis for photoperiodism in Antheraea pernyi based on the transcription regulation of NAT interlocked by the

  17. Metabolite Profile Resulting from the Activation/Inactivation of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine and 2-Methyltetrahydro-β-carboline by Oxidative Enzymes

    Directory of Open Access Journals (Sweden)

    Tomás Herraiz

    2013-01-01

    Full Text Available Metabolic enzymes are involved in the activation/deactivation of the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyiridine (MPTP neurotoxin and its naturally occurring analogs 2-methyltetrahydro-β-carbolines. The metabolic profile and biotransformation of these protoxins by three enzymes, monoamine oxidase (MAO, cytochrome P450, and heme peroxidases (myeloperoxidase and lactoperoxidase, were investigated and compared. The metabolite profile differed among the enzymes investigated. MAO and heme peroxidases activated these substances to toxic pyridinium and β-carbolinium species. MAO catalyzed the oxidation of MPTP to 1-methyl-4-phenyl-2,3-dihydropyridinium cation (MPDP+, whereas heme peroxidases catalyzed the oxidation of MPDP+ to 1-methyl-4-phenylpyridinium (MPP+ and of 2-methyltetrahydro-β-carboline to 2-methyl-3,4-dihydro-β-carbolinium cation (2-Me-3,4-DHβC+. These substances were inactivated by cytochrome P450 2D6 through N-demethylation and aromatic hydroxylation (MPTP and aromatic hydroxylation (2-methyltetrahydro-β-carboline. In conclusion, the toxicological effects of these protoxins might result from a balance between the rate of their activation to toxic products (i.e., N-methylpyridinium-MPP+ and MPDP+- and N-methyl-β-carbolinium—βC+— by MAO and heme peroxidases and the rate of inactivation (i.e., N-demethylation, aromatic hydroxylation by cytochrome P450 2D6.

  18. Fermentation Condition of Glycerol Oxidase Producing Strain and Studies on the Properties of the Enzyme%甘油氧化酶发酵条件及酶学性质的研究

    Institute of Scientific and Technical Information of China (English)

    李明春; 任勇; 张琦; 张颖慧; 邢来君

    2004-01-01

    日本曲霉(Aspergillus japonicus Aj113)发酵生产甘油氧化酶(Glycerol Oxidase EC 1.1.3.-)的最适产酶条件:初始pH 6.0-6.5,温度29±1℃,培养时间36h,500ml三角瓶发酵液的装量为100ml;酶的最适作用pH为5.0,该酶在pH9.5,温度30℃以下时稳定性较好;0.05mol/L的硼砂-碳酸钠缓冲液(pH9.5)对酶有较好的保存效果,Zn2+、Cu2+、Fe3+、Ca2+离子对酶有激活作用,Hg2+离子对酶有强烈的抑制作用.

  19. Kinetics of Inhibition of Polyphenol Oxidase Obtained from Tobacco Nicotiana Tobacum

    Institute of Scientific and Technical Information of China (English)

    刘卫群; 饶学明; 潘继承; 周海梦

    2004-01-01

    In this study, the kinetics of inhibition of polyphenol oxidase by L-cysteine has been investigated.The inhibition of tobacco polyphenol oxidase was studied using the progress-of-substrate-reaction method proposed by Tsou, following the substrate reaction during irreversible inhibition of the enzyme activity. Analysis of the inhibition kinetics shows that inhibition occurs by an irreversible and non-complexation reaction. The microscopic rate constants were determined for reaction of the inhibitor both with the free enzyme and with the enzyme-substrate complex. The results show that the presence of the substrate has a significant protective effect of the enzyme against inactivation by L-cysteine.

  20. Human liver enzymes responsible for metabolic elimination of tyramine; a vasopressor agent from daily food.

    Science.gov (United States)

    Niwa, Toshiro; Murayama, Norie; Umeyama, Hiromi; Shimizu, Makiko; Yamazaki, Hiroshi

    2011-08-01

    Dietary tyramine is associated with hypertensive crises because of its ability to induce the release of catecholamines. The roles of monoamine oxidase (MAO); flavin-containing monooxygenase (FMO); and cytochrome P450 2D6 (CYP2D6) were studied in terms of the enzymatic elimination of tyramine in vitro at a substrate concentration of 1.0 µM; which is relevant to in vivo serum concentrations. Tyramine elimination by human liver supernatant fractions was decreased by ˜70% in the absence of NADPH. Pargyline; an MAO inhibitor; decreased tyramine elimination rates by ˜30%. Among recombinant P450 and FMO enzymes; CYP2D6 had a high activity in terms of tyramine elimination. Tyramine elimination rates were inhibited by quinidine and significantly correlated with bufuralol 1'-hydroxylation activities (a CYP2D6 marker). Liver microsomes genotyped for CYP2D6*10/*10 and CYP2D6*4/*4 showed low and undetectable activities; respectively; compared with the wild-type CYP2D6*1/*1. The present results suggest that tyramine is eliminated mainly by polymorphic CYP2D6. Tyramine toxicity resulting from differences in individual metabolic elimination is thus genetically determined.

  1. Multicopper oxidase-1 orthologs from diverse insect species have ascorbate oxidase activity.

    Science.gov (United States)

    Peng, Zeyu; Dittmer, Neal T; Lang, Minglin; Brummett, Lisa M; Braun, Caroline L; Davis, Lawrence C; Kanost, Michael R; Gorman, Maureen J

    2015-04-01

    Members of the multicopper oxidase (MCO) family of enzymes can be classified by their substrate specificity; for example, ferroxidases oxidize ferrous iron, ascorbate oxidases oxidize ascorbate, and laccases oxidize aromatic substrates such as diphenols. Our previous work on an insect multicopper oxidase, MCO1, suggested that it may function as a ferroxidase. This hypothesis was based on three lines of evidence: RNAi-mediated knock down of Drosophila melanogaster MCO1 (DmMCO1) affects iron homeostasis, DmMCO1 has ferroxidase activity, and DmMCO1 has predicted iron binding residues. In our current study, we expanded our focus to include MCO1 from Anopheles gambiae, Tribolium castaneum, and Manduca sexta. We verified that MCO1 orthologs have similar expression profiles, and that the MCO1 protein is located on the basal surface of cells where it is positioned to oxidize substrates in the hemolymph. In addition, we determined that RNAi-mediated knock down of MCO1 in A. gambiae affects iron homeostasis. To further characterize the enzymatic activity of MCO1 orthologs, we purified recombinant MCO1 from all four insect species and performed kinetic analyses using ferrous iron, ascorbate and two diphenols as substrates. We found that all of the MCO1 orthologs are much better at oxidizing ascorbate than they are at oxidizing ferrous iron or diphenols. This result is surprising because ascorbate oxidases are thought to be specific to plants and fungi. An analysis of three predicted iron binding residues in DmMCO1 revealed that they are not required for ferroxidase or laccase activity, but two of the residues (His374 and Asp380) influence oxidation of ascorbate. These two residues are conserved in MCO1 orthologs from insects and crustaceans; therefore, they are likely to be important for MCO1 function. The results of this study suggest that MCO1 orthologs function as ascorbate oxidases and influence iron homeostasis through an unknown mechanism.

  2. A Conserved Steroid Binding Site in Cytochrome c Oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Ling; Mills, Denise A.; Buhrow, Leann; Hiser, Carrie; Ferguson-Miller, Shelagh (Michigan)

    2010-09-02

    Micromolar concentrations of the bile salt deoxycholate are shown to rescue the activity of an inactive mutant, E101A, in the K proton pathway of Rhodobacter sphaeroides cytochrome c oxidase. A crystal structure of the wild-type enzyme reveals, as predicted, deoxycholate bound with its carboxyl group at the entrance of the K path. Since cholate is a known potent inhibitor of bovine oxidase and is seen in a similar position in the bovine structure, the crystallographically defined, conserved steroid binding site could reveal a regulatory site for steroids or structurally related molecules that act on the essential K proton path.

  3. Inhibition of chickpea seedling copper amine oxidases by tetraethylenepentamine

    Directory of Open Access Journals (Sweden)

    Sona Talaei

    2012-01-01

    Full Text Available Copper amine oxidases are important enzymes, which contribute to the regulation of mono- and polyamine levels. Each monomer contains one Cu(II ion and 2,4,5-trihydroxyphenylalanine (TPQ as cofactors. They catalyze the oxidative deamination of primary amines to aldehydes with a ping-pong mechanism consisting of a transamination. The mechanism is followed by the transfer of two electrons to molecular oxygen which is reduced to hydrogen peroxide. Inhibitors are important tools in the study of catalytic properties of copper amine oxidases and they also have a wide application in physiological research. In this study, purification of the chickpea seedling amine oxidase, was done via salting out by ammonium sulfate and dialysis, followed by DEAE-cellulose column chromatography. By using the Lineweaver - Burk plot, the Km and Vm of the enzyme were found to be 3.3 mM and 0.95 mmol/min/mg, respectively. In this study, the interaction of chickpea diamino oxidase with tetraethylene- pentamine was studied. Analysis of kinetic data indicated that tetraethylenepentamine (with Ki=0.1 mM inhibits the enzyme by linear mixed inhibitory effect.

  4. Specific responses of monoamine neurotransmitters to various acute stressors

    Institute of Scientific and Technical Information of China (English)

    Rongrong He; Guanyu Lin; Yifang Li; Keiich Abe; Xinsheng Yao; Hiroshi Kurihara

    2011-01-01

    This study determined the composition of histamine, serotonin and dopamine using high performance liquid chromatography and electrochemical detection, and compared the changes in monoamine levels in plasma, the cortex and midbrain of mice exposed to acute stressors, such as blood-drawing stimulation or restraint. Results demonstrated that plasma histamine levels were markedly increased when mice were exposed to blood-drawing stimulation and restraint stress. However, serotonin levels decreased in plasma of mice treated with restraint stress, and dopamine levels in plasma had no significant response to the two acute stressors. The three monoamines (histamine, serotonin and dopamine) increased at different degrees in restraint mice, but not in brain regions of blood-drawing stressed mice. Results indicated that histaminergic, serotonergic or dopaminergic systems have their own specific response to different acute stressors.

  5. Designing Modulators of Monoamine Transporters using Virtual Screening Techniques

    Directory of Open Access Journals (Sweden)

    Ole Valente Mortensen

    2015-09-01

    Full Text Available The plasma-membrane monoamine transporters (MATs, including the serotonin (SERT, norepinephrine (NET and dopamine (DAT transporters, serve a pivotal role in limiting monoamine-mediated neurotransmission through the reuptake of their respective monoamine neurotransmitters. The transporters are the main target of clinically used psychostimulants and antidepressants. Despite the availability of several potent and selective MAT substrates and inhibitors the continuing need for therapeutic drugs to treat brain disorders involving aberrant monoamine signaling provides a compelling reason to identify novel ways of targeting and modulating the MATs. Designing novel modulators of MAT function have been limited by the lack of three dimensional structure information of the individual MATs. However, crystal structures of LeuT, a bacterial homologue of MATs, in a substrate-bound occluded, substrate-free outward-open, and an apo inward-open state and also with competitive and noncompetitive inhibitors have been determined. In addition, several structures of the drosophila DAT have also been resolved. Together with computational modeling and experimental data gathered over the past decade, these structures have dramatically advanced our understanding of several aspects of SERT, NET, and DAT transporter function, including some of the molecular determinants of ligand interaction at orthosteric substrate and inhibitor binding pockets. In addition progress has been made in the understanding of how allosteric modulation of MAT function can be achieved. Here we will review all the efforts up to date that has been made through computational approaches employing structural models of MATs to design small molecule modulators to the orthosteric and allosteric sites using virtual screening techniques.

  6. Designing modulators of monoamine transporters using virtual screening techniques

    Science.gov (United States)

    Mortensen, Ole V.; Kortagere, Sandhya

    2015-01-01

    The plasma-membrane monoamine transporters (MATs), including the serotonin (SERT), norepinephrine (NET) and dopamine (DAT) transporters, serve a pivotal role in limiting monoamine-mediated neurotransmission through the reuptake of their respective monoamine neurotransmitters. The transporters are the main target of clinically used psychostimulants and antidepressants. Despite the availability of several potent and selective MAT substrates and inhibitors the continuing need for therapeutic drugs to treat brain disorders involving aberrant monoamine signaling provides a compelling reason to identify novel ways of targeting and modulating the MATs. Designing novel modulators of MAT function have been limited by the lack of three dimensional structure information of the individual MATs. However, crystal structures of LeuT, a bacterial homolog of MATs, in a substrate-bound occluded, substrate-free outward-open, and an apo inward-open state and also with competitive and non-competitive inhibitors have been determined. In addition, several structures of the Drosophila DAT have also been resolved. Together with computational modeling and experimental data gathered over the past decade, these structures have dramatically advanced our understanding of several aspects of SERT, NET, and DAT transporter function, including some of the molecular determinants of ligand interaction at orthosteric substrate and inhibitor binding pockets. In addition progress has been made in the understanding of how allosteric modulation of MAT function can be achieved. Here we will review all the efforts up to date that has been made through computational approaches employing structural models of MATs to design small molecule modulators to the orthosteric and allosteric sites using virtual screening techniques. PMID:26483692

  7. Construction of Mutant Glucose Oxidases with Increased Dye-Mediated Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Koji Sode

    2012-11-01

    Full Text Available Mutagenesis studies on glucose oxidases (GOxs were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe and Aspergillus niger GOx (PDB ID; 1cf3. We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor.

  8. Purification and characterization of methylamine oxidase induced in Aspergillus niger AKU 3302.

    Science.gov (United States)

    Frébort, I; Matsushita, K; Toyama, H; Lemr, K; Yamada, M; Adachi, O

    1999-01-01

    Crude extract of Aspergillus niger AKU 3302 mycelia incubated with methylamine showed a single amine oxidase activity band in a developed polyacrylamide gel that weakly cross-reacted with the antibody against a copper/topa quinone-containing amine oxidase (AO-II) from the same strain induced by n-butylamine. Since the organism cannot grow on methylamine and the already known quinoprotein amine oxidases of the organism cannot catalyze oxidation of methylamine, the organism was forced to produce another enzyme that could oxidize methylamine when the mycelia were incubated with methylamine. The enzyme was separated and purified from the already known two quinoprotein amine oxidases formed in the same mycelia. The purified enzyme showed a sharp symmetric sedimentation peak in analytical ultracentrifugation showing S20,w0 of 6.5s. The molecular mass of 133 kDa estimated by gel chromatography and 66.6 kDa found by SDS-PAGE confirmed the dimeric structure of the enzyme. The purified enzyme was pink in color with an absorption maximum at 494 nm. The enzyme readily oxidized methylamine, n-hexylamine, and n-butylamine, but not benzylamine, histamine, or tyramine, favorite substrates for the already known two quinoprotein amine oxidases. Inactivation by carbonyl reagents and copper chelators suggested the presence of a copper/topa quinone cofactor. Spectrophotometric titration by p-nitrophenylhydrazine showed one reactive carbonyl group per subunit and redox-cyclic quinone staining confirmed the presence of a quinone cofactor. pH-dependent shift of the absorption spectrum of the enzyme-p-nitrophenylhydrazone (469 nm at neutral to 577 nm at alkaline pH) supported the identity of the cofactor with topaquinone. Nothern blot analysis indicated that the methylamine oxidase encoding gene is largely different from the already known amine oxidase in the organism.

  9. NAD(P)H oxidase associated superoxide production in human placenta from normotensive and pre-eclamptic women

    NARCIS (Netherlands)

    Raijmakers, M.; Peters, W.H.M.; Steegers, E.A.P.; Poston, L.

    2004-01-01

    Oxidative stress plays an important role in the development of pre-eclampsia. Recently, the superoxide producing enzyme NAD(P)H oxidase was shown to be present in placental trophoblast. In this pilot-study we investigated the NAD(P)H oxidase associated superoxide production as modulator of placental

  10. Crystal Structure of Alcohol Oxidase from Pichia pastoris.

    Directory of Open Access Journals (Sweden)

    Christian Koch

    Full Text Available FAD-dependent alcohol oxidases (AOX are key enzymes of methylotrophic organisms that can utilize lower primary alcohols as sole source of carbon and energy. Here we report the crystal structure analysis of the methanol oxidase AOX1 from Pichia pastoris. The crystallographic phase problem was solved by means of Molecular Replacement in combination with initial structure rebuilding using Rosetta model completion and relaxation against an averaged electron density map. The subunit arrangement of the homo-octameric AOX1 differs from that of octameric vanillyl alcohol oxidase and other dimeric or tetrameric alcohol oxidases, due to the insertion of two large protruding loop regions and an additional C-terminal extension in AOX1. In comparison to other alcohol oxidases, the active site cavity of AOX1 is significantly reduced in size, which could explain the observed preference for methanol as substrate. All AOX1 subunits of the structure reported here harbor a modified flavin adenine dinucleotide, which contains an arabityl chain instead of a ribityl chain attached to the isoalloxazine ring.

  11. Inactivation of nitric oxide by cytochrome c oxidase under steady-state oxygen conditions.

    Science.gov (United States)

    Unitt, David C; Hollis, Veronica S; Palacios-Callender, Miriam; Frakich, Nanci; Moncada, Salvador

    2010-03-01

    We have developed a respiration chamber that allows intact cells to be studied under controlled oxygen (O(2)) conditions. The system measures the concentrations of O(2) and nitric oxide (NO) in the cell suspension, while the redox state of cytochrome c oxidase is continuously monitored optically. Using human embryonic kidney cells transfected with a tetracycline-inducible NO synthase we show that the inactivation of NO by cytochrome c oxidase is dependent on both O(2) concentration and electron turnover of the enzyme. At a high O(2) concentration (70 microM), and while the enzyme is in turnover, NO generated by the NO synthase upon addition of a given concentration of l-arginine is partially inactivated by cytochrome c oxidase and does not affect the redox state of the enzyme or consumption of O(2). At low O(2) (15 microM), when the cytochrome c oxidase is more reduced, inactivation of NO is decreased. In addition, the NO that is not inactivated inhibits the cytochrome c oxidase, further reducing the enzyme and lowering O(2) consumption. At both high and low O(2) concentrations the inactivation of NO is decreased when sodium azide is used to inhibit cytochrome c oxidase and decrease electron turnover.

  12. Origin and evolution of lysyl oxidases.

    Science.gov (United States)

    Grau-Bové, Xavier; Ruiz-Trillo, Iñaki; Rodriguez-Pascual, Fernando

    2015-05-29

    Lysyl oxidases (LOX) are copper-dependent enzymes that oxidize primary amine substrates to reactive aldehydes. The best-studied role of LOX enzymes is the remodeling of the extracellular matrix (ECM) in animals by cross-linking collagens and elastin, although intracellular functions have been reported as well. Five different LOX enzymes have been identified in mammals, LOX and LOX-like (LOXL) 1 to 4, showing a highly conserved catalytic carboxy terminal domain and more divergence in the rest of the sequence. Here we have surveyed a wide selection of genomes in order to infer the evolutionary history of LOX. We identified LOX proteins not only in animals, but also in many other eukaryotes, as well as in bacteria and archaea - which reveals a pre-metazoan origin for this gene family. LOX genes expanded during metazoan evolution resulting in two superfamilies, LOXL2/L3/L4 and LOX/L1/L5. Considering the current knowledge on the function of mammalian LOX isoforms in ECM remodeling, we propose that LOXL2/L3/L4 members might have preferentially been involved in making cross-linked collagen IV-based basement membrane, whereas the diversification of LOX/L1/L5 forms contributed to chordate/vertebrate-specific ECM innovations, such as elastin and fibronectin. Our work provides a novel view on the evolution of this family of enzymes.

  13. Retinal ganglion cells of high cytochrome oxidase activity in the rat

    Institute of Scientific and Technical Information of China (English)

    JENLS; CHAURMW

    1990-01-01

    Retinal ganglion cells in the rat were studied using the heavy metal intensified cytochrome oxidase and horseradish peroxidase histochemical methods.The results show that a population of large retinal ganglion cells was consistently observed with the cytochrome oxidase staining method in retinas of normal rats or rats which received unilateral thalamotomy at birth.These cytochrome oxidase rich ganglion cells appeared to have large somata,3-6 primary dendrites and extensive dendritic arbors,and are comparable to ganglion cells labeled by the wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP).However,the morphological details of some of the cells revealed by the cytochrome oxidase staining method are frequently better than those shown by the HRP histochemical method.These results suggest that the mitochondrial enzyme cytochrome oxidase can be used as a simple but reliable marker for identifying and studying a population of retinal genglion cells with high metabolic rate in the rat.

  14. Layer-by-Layer Assembly of Enzymes on Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun; Liu, Guodong; Lin, Yuehe

    2008-06-01

    The use of Layer-by-layer techniques for immobilizing several types of enzymes, e.g. glucose oxidase (GOx), horse radish oxidases(HRP), and choline oxidase(CHO) on carbon nanotubes and their applications for biosenseing are presented. The enzyme is immobilized on the negatively charged CNT surface by alternatively assembling a cationic polydiallyldimethyl-ammonium chloride (PDDA) layer and a enzyme layer. The sandwich-like layer structure (PDDA/enzyme/PDDA/CNT) formed by electrostatic assembling provides a favorable microenvironment to keep the bioactivity of enzyme and to prevent enzyme molecule leakage. The morphologies and electrocatalytic acitivity of the resulted enzyme film were characterized using TEM and electrochemical techniques, respectively. It was found that these enzyme-based biosensors are very sensitive, selective for detection of biomolecules, e.g. glucose, choline.

  15. Generation of proton-motive force by an archaeal terminal quinol oxidase from Sulfolobus acidocaldarius

    NARCIS (Netherlands)

    Gleissner, Michael; Elferink, Maria; Driessen, Arnold J.M.; Konings, Wilhelmus; Anemüller, Stefan; Schäfer, Günter

    1994-01-01

    The terminal quinol oxidase of the cytochrome aa3 type was isolated from the extreme thermo-acidophilic archaeon Sulfolobus acidocaldarius. In micellar solution, the enzyme oxidized various quinols and exerted the highest activity with the physiological substrate caldariella quinol. The enzyme was f

  16. Neuronal monoamine reuptake inhibitors enhance in vitro susceptibility to chloroquine in resistant Plasmodium falciparum.

    OpenAIRE

    Coutaux, A F; Mooney, J. J.; Wirth, D. F.

    1994-01-01

    Chloroquine resistance in Plasmodium falciparum was reversed in vitro by the neuronal monoamine reuptake inhibitors and antidepressants desipramine, sertraline, fluoxetine, and norfluoxetine but not by carbamazepine, an antiseizure and mood-stabilizing tricyclic drug resembling desipramine which only weakly inhibits neuronal monoamine reuptake. These findings have important clinical implications for drug combination therapy.

  17. Properties of purified recombinant human polyamine oxidase, PAOh1/SMO.

    Science.gov (United States)

    Wang, Yanlin; Murray-Stewart, Tracy; Devereux, Wendy; Hacker, Amy; Frydman, Benjamin; Woster, Patrick M; Casero, Robert A

    2003-05-16

    The discovery of an inducible oxidase whose apparent substrate preference is spermine indicates that polyamine catabolism is more complex than that originally proposed. To facilitate the study of this enzyme, the purification and characterization of the recombinant human PAOh1/SMO polyamine oxidase are reported. Purified PAOh1/SMO oxidizes both spermine (K(m)=1.6 microM) and N(1)-acetylspermine (K(m)=51 microM), but does not oxidize spermidine. The purified human enzyme also does not oxidize eight representative antitumor polyamine analogues; however, specific oligamine analogues were found to be potent inhibitors of the oxidation of spermine by PAOh1/SMO. The results of these studies are consistent with the hypothesis that PAOh1/SMO represents a new addition to the polyamine metabolic pathway that may represent a new target for antineoplastic drug development.

  18. Intramolecular electron transfer in ascorbate oxidase is enhanced in the presence of oxygen

    DEFF Research Database (Denmark)

    Farver, O; Wherland, S; Pecht, I

    1994-01-01

    Intramolecular electron transfer from the type 1 copper center to the type 3 copper(II) pair is induced in the multi-copper enzyme, ascorbate oxidase, following pulse radiolytic reduction of the type 1 Cu(II) ion. In the presence of a slight excess of dioxygen over ascorbate oxidase, interaction...... between the trinuclear copper center and O2 is observed even with singly reduced ascorbate oxidase molecules. Under these conditions, the rate constant for intramolecular electron transfer from type 1 Cu(I) to type 3 Cu(II) increases 5-fold to 1100 +/- 300 s-1 (20 degrees C, pH 5.8) as compared...

  19. Inventory control: cytochrome oxidase assembly regulates mitochondrial translation

    Science.gov (United States)

    Mick, David U.; Fox, Thomas D.; Rehling, Peter

    2012-01-01

    Mitochondria maintain a genome and translation-machinery to synthesize a small subset of subunits of the oxidative phosphorylation system. These organellar gene products must assemble with imported subunits that are encoded in the nucleus to build up functional enzymes. New findings on the early steps in cytochrome oxidase assembly reveal how the mitochondrial translation of its core component Cox1 is directly coupled to the assembly of this respiratory complex. PMID:21179059

  20. Artificial Enzymes, "Chemzymes"

    DEFF Research Database (Denmark)

    Bjerre, Jeannette; Rousseau, Cyril Andre Raphaël; Pedersen, Lavinia Georgeta M

    2008-01-01

    Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models that successf......Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models...... that successfully perform Michaelis-Menten catalysis under enzymatic conditions (i.e., aqueous medium, neutral pH, ambient temperature) and for those that do, very high rate accelerations are seldomly seen. This review will provide a brief summary of the recent developments in artificial enzymes, so called...... "Chemzymes", based on cyclodextrins and other molecules. Only the chemzymes that have shown enzyme-like activity that has been quantified by different methods will be mentioned. This review will summarize the work done in the field of artificial glycosidases, oxidases, epoxidases, and esterases, as well...

  1. NADPH Oxidases in Chronic Liver Diseases

    Directory of Open Access Journals (Sweden)

    Joy X. Jiang

    2014-01-01

    Full Text Available Oxidative stress is a common feature observed in a wide spectrum of chronic liver diseases including viral hepatitis, alcoholic, and nonalcoholic steatohepatitis. The nicotinamide adenine dinucleotide phosphate (NADPH oxidases (NOXs are emerging as major sources of reactive oxygen species (ROS. Several major isoforms are expressed in the liver, including NOX1, NOX2, and NOX4. While the phagocytic NOX2 has been known to play an important role in Kupffer cell and neutrophil phagocytic activity and inflammation, the nonphagocytic NOX homologues are increasingly recognized as key enzymes in oxidative injury and wound healing. In this review, we will summarize the current advances in knowledge on the regulatory pathways of NOX activation, their cellular distribution, and their role in the modulation of redox signaling in liver diseases.

  2. Inhibitory activity of xanthine oxidase by fractions Crateva adansonii

    Institute of Scientific and Technical Information of China (English)

    Abdullahi A; Kolo MZ; Hamzah RU; Jigam AA; Yahya A; Kabiru AY; Muhammad H; Sakpe S; Adefolalu FS; Isah MC

    2012-01-01

    Objective: To study the inhibitory effect of various extracts from Crateva adansonii (C. adansonii) used traditionally against several inflammatory diseases such as rheumatism, arthritis, and gout, was investigated on purified bovine milk xanthine oxidase (XO) activity. Methods:Xanthine oxidase inhibitory activity was assayed spectrophotometrically and the degree of enzyme inhibition was determined by measuring the increase in absorbance at 295 nm associated with uric acid formation. Enzyme kinetics was carried out using Lineweaver-Burk plots using xanthine as the substrate. Results: Among the fractions tested, the chloroform fraction exhibited highest potency (IC50 20.2±1.6 μg/mL) followed by the petroleum ether (IC50 30.1±2.2 μg/mL), ethyl acetate (IC50 43.9±1.4 μg/mL) and residual (IC50 98.0±3.3 μg/mL) fractions. The IC50 value of allopurinol used, as the standard was 5.7±0.3 μg/mL. Conclusions: Enzyme inhibition mechanism indicated that the mode of inhibition was of a mixed type. Our findings suggest that the therapeutic use of these plants may be due to the observed Xanthine oxidase inhibition, thereby supporting their use in traditional folk medicine against inflammatory-related diseases, in particular, gout.

  3. Surface characterization and direct bioelectrocatalysis of multicopper oxidases

    Energy Technology Data Exchange (ETDEWEB)

    Ivnitski, Dmitri M., E-mail: ivnitski@unm.ed [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States)] [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States); Khripin, Constantine [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States); Luckarift, Heather R. [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States)] [Universal Technology Corporation, 1270 N. Fairfield Road, Dayton, OH 45432 (United States); Johnson, Glenn R. [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States); Atanassov, Plamen, E-mail: plamen@unm.ed [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States)

    2010-10-01

    Multicopper oxidases (MCO) have been extensively studied as oxygen reduction catalysts for cathodic reactions in biofuel cells. Theoretically, direct electron transfer between an enzyme and electrode offers optimal energy conversion efficiency providing that the enzyme/electrode interface can be engineered to establish efficient electrical communication. In this study, the direct bioelectrocatalysis of three MCO (Laccase from Trametes versicolor, bilirubin oxidase (BOD) from the fungi Myrothecium verrucaria and ascorbate oxidase (AOx) from Cucurbita sp.) was investigated and compared as oxygen reduction catalysts. Protein film voltammetry and electrochemical characterization of the MCO electrodes showed that DET had been successfully established in all cases. Atomic force microscopy imaging and force measurements indicated that enzyme was immobilized as a monolayer on the electrode surface. Evidence for three clearly separated anodic and cathodic redox events related to the Type 1 (T1) and the trinculear copper centers (T2, T3) of various MCO was observed. The redox potential of the T1 center was strongly modulated by physiological factors including pH, anaerobic and aerobic conditions and the presence of inhibitors.

  4. Catecholamines and their enzymes in discrete brain areas of rats after space flight on biosatellites Cosmos.

    Science.gov (United States)

    Kvetnansky, R; Culman, J; Serova, L V; Tigranjan, R A; Torda, T; Macho, L

    1983-01-01

    The activity of the catecholaminergic system was measured in the hypothalamus of rats which had experienced an 18.5-19.5-day-long stay in the state of weightlessness during space flights on board Soviet biosatellites of the type Cosmos. In the first two experiments, Cosmos 782 and 936, the concentration of norepinephrine and the activities of synthesizing enzymes tyrosine hydroxylase and dopamine-beta-hydroxylase and of the degrading enzyme monoamine oxidase were measured in the total hypothalamus. None of the given parameters was changed after space flight. In the light of the changes of these parameters recorded after exposure to acute stress on Earth, this finding indicates that long-term state of weightlessness does not represent an intensive stressogenic stimulus for the system studied. In the space experiment Cosmos 1129, the concentration of norepinephrine, epinephrine, and dopamine was studied in isolated nuclei of the hypothalamus of rats within 6-10 hr following return from space. Norepinephrine was found to be significantly reduced in the arcuate nucleus, median eminence and periventricular nucleus, epinephrine in the median eminence, periventricular and suprachiasmatic nuclei, whereas dopamine was not significantly changed after space flight. The decreased catecholamine levels found in some hypothalamic nuclei of rats which had undergone space flight indicate that no chronic intensive stressor could have acted during the flight, otherwise the catecholamine concentration would have been increased in the nuclei. The decreased levels must have been induced by the effect of a stressogenic factor acting for a short time only, and that either during the landing maneuver or immediately after landing. Thus long-term exposure of the organism to the state of weightlessness does not represent a stressogenic stimulus for the catecholaminergic system in the hypothalamus, which is one of the regulators of the activation of neuroendocrine reactions under stress.

  5. CotA, a multicopper oxidase from Bacillus pumilus WH4, exhibits manganese-oxidase activity.

    Directory of Open Access Journals (Sweden)

    Jianmei Su

    Full Text Available Multicopper oxidases (MCOs are a family of enzymes that use copper ions as cofactors to oxidize various substrates. Previous research has demonstrated that several MCOs such as MnxG, MofA and MoxA can act as putative Mn(II oxidases. Meanwhile, the endospore coat protein CotA from Bacillus species has been confirmed as a typical MCO. To study the relationship between CotA and the Mn(II oxidation, the cotA gene from a highly active Mn(II-oxidizing strain Bacillus pumilus WH4 was cloned and overexpressed in Escherichia coli strain M15. The purified CotA contained approximately four copper atoms per molecule and showed spectroscopic properties typical of blue copper oxidases. Importantly, apart from the laccase activities, the CotA also displayed substantial Mn(II-oxidase activities both in liquid culture system and native polyacrylamide gel electrophoresis. The optimum Mn(II oxidase activity was obtained at 53°C in HEPES buffer (pH 8.0 supplemented with 0.8 mM CuCl2. Besides, the addition of o-phenanthroline and EDTA both led to a complete suppression of Mn(II-oxidizing activity. The specific activity of purified CotA towards Mn(II was 0.27 U/mg. The Km, Vmax and kcat values towards Mn(II were 14.85±1.17 mM, 3.01×10(-6±0.21 M·min(-1 and 0.32±0.02 s(-1, respectively. Moreover, the Mn(II-oxidizing activity of the recombinant E. coli strain M15-pQE-cotA was significantly increased when cultured both in Mn-containing K liquid medium and on agar plates. After 7-day liquid cultivation, M15-pQE-cotA resulted in 18.2% removal of Mn(II from the medium. Furthermore, the biogenic Mn oxides were clearly observed on the cell surfaces of M15-pQE-cotA by scanning electron microscopy. To our knowledge, this is the first report that provides the direct observation of Mn(II oxidation with the heterologously expressed protein CotA, Therefore, this novel finding not only establishes the foundation for in-depth study of Mn(II oxidation mechanisms, but also offers

  6. Partial purification and characterization of polyphenol oxidase from persimmon.

    Science.gov (United States)

    Navarro, José L; Tárrega, Amparo; Sentandreu, Miguel A; Sentandreu, Enrique

    2014-08-15

    Activity of polyphenol oxidase (PPO) from "Rojo Brillante" persimmon (Diospyros kaki L.) fruits was characterized. Crude extracts were used for characterization of enzyme activity and stability at different temperatures (60, 70 and 80 °C), pHs (from 3.5 to 7.5) and substrate concentrations (catechol from 0 to 0.5M). Maximum enzyme activity was reached at pH 5.5 and 55 °C. Enzyme stability was higher than PPO activities found in other natural sources, since above pH 5.5 the minimum time needed to achieve an enzyme inactivation of 90% was 70 min at 80 °C. However, at pH 4.0 the enzyme stability decreased, reaching inactivation levels above 90% after 10 min even at 60 °C. Thus it was concluded that acidification can circumvent browning problems caused by PPO activity. Moreover, polyacrylamide gel electrophoresis of the enriched extract revealed the presence of at least four bands with strong oxidase activity, suggesting the existence of different PPO isoforms.

  7. Inhibition of in vivo histamine metabolism in rats by foodborne and pharmacologic inhibitors of diamine oxidase, histamine N-methyltransferase, and monoamine oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Hui, J.Y.; Taylor, S.L.

    1985-11-01

    When (/sup 14/C)histamine was administered orally to rats, an average of 80% of the administered radioactivity was recovered in the urine at the end of 24 hr. About 10% of the total dose was excreted via the feces. Analysis of 4-hr urine samples found imidazoleacetic acid to be the predominant metabolite (60.6%), with N tau-methylimidazoleacetic acid (8.6%), N tau-methylhistamine (7.3%), and N-acetylhistamine (4.5%) to be the minor metabolites. Histamine metabolism was inhibited by simultaneous oral administration of aminoguanidine, isoniazid, quinacrine, cadaverine, putrescine, tyramine, and beta-phenylethylamine. The administration of inhibitors resulted in an increased amount of unmetabolized histamine and a decreased amount of metabolites reaching the urine. Pharmacologic inhibitors were found to be more potent and have a longer duration of action than foodborne ones. The inhibitors could potentiate food poisoning caused by histamine by inhibiting its metabolism.

  8. Conductometric transducers for enzyme-based biosensors.

    Science.gov (United States)

    Mikkelsen, S R; Rechnitz, G A

    1989-08-01

    The use of alternating current conductometric transducers in biosensing devices has been investigated for urea and D-amino acid sensors using the enzyme systems urease and D-amino acid oxidase/catalase. Transducers with copper and platinum electrodes were constructed and characterized, and two enzyme immobilization methods were tested. Detection limits of 1 x 10(-6)M and linear ranges of 2 orders of magnitude were routinely achieved for these model sensors with enzymes covalently immobilized on collagen films.

  9. Enzymatic characterization and in vivo function of five terminal oxidases in Pseudomonas aeruginosa.

    Science.gov (United States)

    Arai, Hiroyuki; Kawakami, Takuro; Osamura, Tatsuya; Hirai, Takehiro; Sakai, Yoshiaki; Ishii, Masaharu

    2014-12-01

    The ubiquitous opportunistic pathogen Pseudomonas aeruginosa has five aerobic terminal oxidases: bo(3)-type quinol oxidase (Cyo), cyanide-insensitive oxidase (CIO), aa3-type cytochrome c oxidase (aa3), and two cbb(3)-type cytochrome c oxidases (cbb(3)-1and cbb(3)-2). These terminal oxidases are differentially regulated under various growth conditions and are thought to contribute to the survival of this microorganism in a wide variety of environmental niches. Here, we constructed multiple mutant strains of P. aeruginosa that express only one aerobic terminal oxidase to investigate the enzymatic characteristics and in vivo function of each enzyme. The Km values of Cyo, CIO, and aa3 for oxygen were similar and were 1 order of magnitude higher than those of cbb(3)-1 and cbb(3)-2, indicating that Cyo, CIO, and aa3 are low-affinity enzymes and that cbb(3)-1 and cbb(3)-2 are high-affinity enzymes. Although cbb(3)-1 and cbb(3)-2 exhibited different expression patterns in response to oxygen concentration, they had similar Km values for oxygen. Both cbb(3)-1 and cbb(3)-2 utilized cytochrome c4 as the main electron donor under normal growth conditions. The electron transport chains terminated by cbb(3)-1 and cbb(3)-2 generate a proton gradient across the cell membrane with similar efficiencies. The electron transport chain of aa3 had the highest proton translocation efficiency, whereas that of CIO had the lowest efficiency. The enzymatic properties of the terminal oxidases reported here are partially in agreement with their regulatory patterns and may explain the environmental adaptability and versatility of P. aeruginosa.

  10. Purification of gibberellin sub 53 -oxidase from spinach

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, T.M.; Zeevaart, J.A.D. (Michigan State Univ., East Lansing (USA))

    1989-04-01

    Spinach is a long-day rosette plants, in which stem growth is mediated by gibberellins. It has been shown that two enzymatic steps, GA{sub 53}-oxidase and GA{sub 19}-oxidase, are controlled by light. To develop an understanding into this light regulation, purification of GA{sub 53}-oxidase has been undertaken. The original assay relied on the HPLC separation of the product and substrate, but was considered too slow for the development of a purification scheme. A TLC system was developed which in conjunction with improvements to the assay conditions was sensitive and gave rapid results. The partial purification of the GA{sub 53}-oxidase is achieved by a high speed centrifugation, 40-55% ammonium sulfate precipitation, an hydroxyapatite column, Sephadex G-100 column and an anion exchange FPLC column, Mono Q HR10/10, yielding 1000-fold purification and 15% recovery. Monoclonal antibodies to the protein will be raised and used to further characterize the enzyme.

  11. Molecular dynamics in cytochrome c oxidase Moessbauer spectra deconvolution

    Energy Technology Data Exchange (ETDEWEB)

    Bossis, Fabrizio [Department of Medical Biochemistry, Medical Biology and Medical Physics (DIBIFIM), University of Bari ' Aldo Moro' , Bari (Italy); Palese, Luigi L., E-mail: palese@biochem.uniba.it [Department of Medical Biochemistry, Medical Biology and Medical Physics (DIBIFIM), University of Bari ' Aldo Moro' , Bari (Italy)

    2011-01-07

    Research highlights: {yields} Cytochrome c oxidase molecular dynamics serve to predict Moessbauer lineshape widths. {yields} Half height widths are used in modeling of Lorentzian doublets. {yields} Such spectral deconvolutions are useful in detecting the enzyme intermediates. -- Abstract: In this work low temperature molecular dynamics simulations of cytochrome c oxidase are used to predict an experimentally observable, namely Moessbauer spectra width. Predicted lineshapes are used to model Lorentzian doublets, with which published cytochrome c oxidase Moessbauer spectra were simulated. Molecular dynamics imposed constraints to spectral lineshapes permit to obtain useful information, like the presence of multiple chemical species in the binuclear center of cytochrome c oxidase. Moreover, a benchmark of quality for molecular dynamic simulations can be obtained. Despite the overwhelming importance of dynamics in electron-proton transfer systems, limited work has been devoted to unravel how much realistic are molecular dynamics simulations results. In this work, molecular dynamics based predictions are found to be in good agreement with published experimental spectra, showing that we can confidently rely on actual simulations. Molecular dynamics based deconvolution of Moessbauer spectra will lead to a renewed interest for application of this approach in bioenergetics.

  12. Functional characterization of gibberellin oxidases from cucumber, Cucumis sativus L.

    Science.gov (United States)

    Pimenta Lange, Maria João; Liebrandt, Anja; Arnold, Linda; Chmielewska, Sara-Miriam; Felsberger, André; Freier, Eduard; Heuer, Monika; Zur, Doreen; Lange, Theo

    2013-06-01

    Cucurbits have been used widely to elucidate gibberellin (GA) biosynthesis. With the recent availability of the genome sequence for the economically important cucurbit Cucumis sativus, sequence data became available for all genes potentially involved in GA biosynthesis for this species. Sixteen cDNAs were cloned from root and shoot of 3-d to 7-d old seedlings and from mature seeds of C. sativus. Two cDNAs code for GA 7-oxidases (CsGA7ox1, and -2), five for GA 20-oxidases (CsGA20ox1, -2, -3, -4, and -5), four for GA 3-oxidases (CsGA3ox1, -2, -3, and -4), and another five for GA 2-oxidases (CsGA2ox1, -2, -3, -4, and -5). Their enzymatic activities were investigated by heterologous expression of the cDNAs in Escherichia coli and incubation of the cell lysates with (14)C-labelled, D2-labelled, or unlabelled GA-substrates. The two GA 7-oxidases converted GA12-aldehyde to GA12 efficiently. CsGA7ox1 converted GA12 to GA14, to 15α-hydroxyGA12, and further to 15α-hydroxyGA14. CsGA7ox2 converted GA12 to its 12α-hydroxylated analogue GA111. All five GA 20-oxidases converted GA12 to GA9 as a major product, and to GA25 as a minor product. The four GA 3-oxidases oxidized the C19-GA GA9 to GA4 as the only product. In addition, three of them (CsGA3ox2, -3, and -4) converted the C20-GA GA12 to GA14. The GA 2-oxidases CsGA2ox1, -2, -3, and -4 oxidized the C19-GAs GA9 and GA4 to GA34 and GA51, respectively. CsGA2ox2, -3, and -4 converted GA51 and GA34 further to respective GA-catabolites. In addition to C19-GAs, CsGA2ox4 also converted the C20-GA GA12 to GA110. In contrast, CsGA2ox5 oxidized only the C20 GA12 to GA110 as the sole product. As shown for CsGA20ox1 and CsGA3ox1, similar reactions were catalysed with 13-hydroxlyated GAs as substrates. It is likely that these enzymes are also responsible for the biosynthesis of 13-hydroxylated GAs in vivo that occur at low levels in cucumber.

  13. Expression of alternative oxidase in tomato

    Energy Technology Data Exchange (ETDEWEB)

    Kakefuda, M.; McIntosh, L. (Michigan State Univ., East Lansing (USA))

    1990-05-01

    Tomato fruit ripening is characterized by an increase in ethylene biosynthesis, a burst in respiration (i.e. the climacteric), fruit softening and pigmentation. As whole tomatoes ripened from mature green to red, there was an increase in the alternative oxidase capacity. Aging pink tomato slices for 24 and 48 hrs also showed an increase of alternative oxidase and cytochrome oxidase capacities. Monoclonal antibodies prepared to the Sauromatum guttatum alternative oxidase were used to follow the appearance of alternative oxidase in tomato fruits. There is a corresponding increase in a 36kDa protein with an increase in alternative oxidase capacity. Effects of ethylene and norbornadiene on alternative oxidase capacity were also studied. We are using an alternative oxidase cDNA clone from potato to study the expression of mRNA in ripening and wounded tomatoes to determine if the gene is transcriptionally regulated.

  14. Phenol oxidase activity in secondary transformed peat-moorsh soils

    Science.gov (United States)

    Styła, K.; Szajdak, L.

    2009-04-01

    The chemical composition of peat depends on the geobotanical conditions of its formation and on the depth of sampling. The evolution of hydrogenic peat soils is closely related to the genesis of peat and to the changes in water conditions. Due to a number of factors including oscillation of ground water level, different redox potential, changes of aerobic conditions, different plant communities, and root exudes, and products of the degradation of plant remains, peat-moorsh soils may undergo a process of secondary transformation conditions (Sokolowska et al. 2005; Szajdak et al. 2007). Phenol oxidase is one of the few enzymes able to degrade recalcitrant phenolic materials as lignin (Freeman et al. 2004). Phenol oxidase enzymes catalyze polyphenol oxidation in the presence of oxygen (O2) by removing phenolic hydrogen or hydrogenes to from radicals or quinines. These products undergo nucleophilic addition reactions in the presence or absence of free - NH2 group with the eventual production of humic acid-like polymers. The presence of phenol oxidase in soil environments is important in the formation of humic substances a desirable process because the carbon is stored in a stable form (Matocha et al. 2004). The investigations were carried out on the transect of peatland 4.5 km long, located in the Agroecological Landscape Park host D. Chlapowski in Turew (40 km South-West of Poznań, West Polish Lowland). The sites of investigation were located along Wyskoć ditch. The following material was taken from four chosen sites marked as Zbechy, Bridge, Shelterbelt and Hirudo in two layers: cartel (0-50cm) and cattle (50-100cm). The object of this study was to characterize the biochemical properties by the determination of the phenol oxidize activity in two layers of the four different peat-moors soils used as meadow. The phenol oxidase activity was determined spectrophotometrically by measuring quinone formation at λmax=525 nm with catechol as substrate by method of Perucci

  15. A novel terminal oxidase, cytochrome baa3 purified from aerobically grown Pseudomonas aeruginosa: it shows a clear difference between resting state and pulsed state.

    Science.gov (United States)

    Fujiwara, T; Fukumori, Y; Yamanaka, T

    1992-08-01

    A novel type of cytochrome c oxidase was purified to homogeneity from Pseudomonas aeruginosa which was grown aerobically. The purified oxidase contained two molecules of heme a, two atoms of copper, and one molecule of protoheme per molecule. One of the two heme a molecules in the oxidase reacted with carbon monoxide, so that the enzyme was of baa3-type. The oxidase molecule was composed of three subunits with molecular weights of 38,000, 57,000, and 82,000. Although the oxidase oxidized ferrocytochrome c-550 obtained from the bacterial cells grown aerobically, the oxidizing activity was not high. The "resting form" and the "pulsed form" of the oxidase were observed clearly with this enzyme, and the transition from the resting form to the pulsed form was accompanied by a distinct change of the enzymatic activity. The difference in the kinetics of the catalytic reactions between the two forms is discussed.

  16. Association of a Monoamine Oxidase-A Gene Promoter Polymorphism with ADHD and Anxiety in Boys with Autism Spectrum Disorder

    Science.gov (United States)

    Roohi, Jasmin; DeVincent, Carla J.; Hatchwell, Eli; Gadow, Kenneth D.

    2009-01-01

    The aim of the present study was to examine the association between a variable number tandem repeat (VNTR) functional polymorphism in the promoter region of the MAO-A gene and severity of ADHD and anxiety in boys with ASD. Parents and teachers completed a DSM-IV-referenced rating scale for 5- to 14-year-old boys with ASD (n = 43). Planned…

  17. Cognitive aspects of congenital learned helplessness and its reversal by the monoamine oxidase (MAO)-B inhibitor deprenyl

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, D.; Schulz, D.; Mirrione, M.; Henn, F.A.

    2009-11-29

    Cognitive processes are assumed to change with learned helplessness, an animal model of depression, but little is known about such deficits. Here we investigated the role of cognitive and related functions in selectively bred helpless (cLH, n = 10), non-helpless (cNLH, n = 12) and wild type (WT, n = 8) Sprague Dawley rats. The animals were exposed to an open field for 10 min on each of two test days. On the third day, an object exploration paradigm was carried out. The animals were later tested for helplessness. Both cLH and cNLH rats were more active than WTs on the first day in the open field. Over trials, cNLH and WT rats lowered their activity less than cLH rats. This resistance-to-habituation co-varied with a resistance to develop helplessness. In cLH rats, higher 'anxiety' or less time spent in the center of the open field co-varied with severe helplessness. In WTs, a greater reactivity to novel objects and to a spatially relocated object predicted lower levels of helplessness. In cLH rats (n = 4-5 per group), chronic treatment with a high dose of the monoamineoxidase (MAO)-Binhibitordeprenyl (10 mg/kg; i.p.), an anti-Parkinson, nootropic and antidepressant drug, attenuated helplessness. Remarkably, helplessness reversal required the experience of repeated test trials, reminiscent of a learning process. Chronic deprenyl (10 mg/kg; i.p.) did not alter locomotion/exploration or 'anxiety' in the open field. In conclusion, helplessness may be related to altered mechanisms of reinforcement learning and working memory, and to abnormalities in MAO-A and/or MAO-B functioning.

  18. The plasma membrane monoamine transporter (PMAT): Structure, function, and role in organic cation disposition.

    Science.gov (United States)

    Wang, J

    2016-11-01

    Plasma membrane monoamine transporter (PMAT) is a new polyspecific organic cation transporter that transports a variety of biogenic amines and xenobiotic cations. Highly expressed in the brain, PMAT represents a major uptake2 transporter for monoamine neurotransmitters. At the blood-cerebrospinal fluid (CSF) barrier, PMAT is the principal organic cation transporter for removing neurotoxins and drugs from the CSF. Here I summarize our latest understanding of PMAT and its roles in monoamine uptake and xenobiotic disposition. © 2016 American Society for Clinical Pharmacology and Therapeutics.

  19. Spectroscopic studies of copper enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, D.M.; Moog, R.; Zumft, W.; Koenig, S.H.; Scott, R.A.; Cote, C.E.; McGuirl, M.

    1986-05-01

    Several spectroscopic methods, including absorption, circular dichroism (CD), magnetic CD (MCD), X-ray absorption, resonance Raman, EPR, NMR, and quasi-elastic light-scattering spectroscopy, have been used to probe the structures of copper-containing amine oxidases, nitrite reductase, and nitrous oxide reductase. The basic goals are to determine the copper site structure, electronic properties, and to generate structure-reactivity correlations. Collectively, the results on the amine oxidases permit a detailed model for the Cu(II) sites in these enzymes to be constructed that, in turn, rationalizes the ligand-binding chemistry. Resonance Raman spectra of the phenylhydrazine and 2,4-dinitrophenyl-hydrazine derivatives of bovine plasma amine oxidase and models for its organic cofactor, e.g. pyridoxal, methoxatin, are most consistent with methoxatin being the intrinsic cofactor. The structure of the Cu(I) forms of the amine oxidases have been investigated by X-ray absorption spectroscopy (XAS); the copper coordination geometry is significantly different in the oxidized and reduced forms. Some anomalous properties of the amine oxidases in solution are explicable in terms of their reversible aggregation, which the authors have characterized via light scattering. Nitrite and nitrous oxide reductases display several novel spectral properties. The data suggest that new types of copper sites are present.

  20. In silico docking studies and in vitro xanthine oxidase inhibitory activity of commercially available terpenoids

    Directory of Open Access Journals (Sweden)

    MUTHUSWAMY UMAMAHESWARI

    2012-11-01

    Full Text Available Objective Xanthine oxidase is a highly versatile enzyme that is widely distributed among different species. The hydroxylation of purines is catalysed by xanthine oxidase and especially the conversion of xanthine to uric acid. Xanthine oxidase inhibitors are much useful, since they possess lesser side effects compared to uricosuric and anti-inflammatory agents. The present study deals with in silico and in vitro xanthine oxidase inhibitory analysis of commercially available terpenoids (bisabolol, β-caryophyllene, limonene, and α- terpinene. Methods Molecular docking studies were performed using AutoDock 4.2 and in vitro xanthine oxidase inhibitory activity was carried out using xanthine as the substrate. In addition, enzyme kinetics was performed using Lineweaver Burkplot analysis. Allopurinol, a known xanthine oxidase inhibitor was used as the standard. Results The results revealed that bisabolol exhibited a lowest binding energy value of about -7.33 kcal/mol. All other compounds showed binding energy values ranging between -7.33 to -5.87 kcal/mol which was less than the standard (-4.78 kcal/mol. In the xanthine oxidase assay, IC50 value of bisabolol was found to be 34.70 µg/ml, whereas that of allopurinol was 8.48 µg/ml. All the remaining compounds exhibited IC50 values ranging between 34.70 to 68.45 µg/ml.  In the enzyme kinetic studies, bisabolol, β-caryophyllene showed non competitive and Limonene, α- terpinene and allopurinol showed competitive type of enzyme inhibition. Conclusion It can be concluded that terpenoids could be a promising remedy for the treatment of gout and related inflammatory disorders. Further in vivo studies are required to develop potential compounds with lesser side effects.

  1. Purification and characterization of a novel caffeine oxidase from Alcaligenes species.

    Science.gov (United States)

    Mohapatra, B R; Harris, N; Nordin, R; Mazumder, A

    2006-09-18

    Alcaligenes species CF8 isolated from surface water of a lake produced a novel serine type metallo-caffeine oxidase. The optimal medium for caffeine oxidase production by this strain was (w/v) NaNO(3), 0.4%; KH(2)PO(4), 0.15%; Na(2)HPO(4), 0.05%; FeCl(3).6H(2)O, 0.0005%; CaCl(2).2H(2)O, 0.001%; MgSO(4).7H(2)O, 0.02%; glucose, 0.2%; caffeine, 0.05%, pH 7.5. The enzyme was purified to 63-fold by using ammonium sulfate precipitation, dialysis, ion exchange (diethylaminoethyl-cellulose) and gel filtration (Sephadex G-100) chromatographic techniques. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified caffeine oxidase was monomeric with a molecular mass of 65 kDa. The purified caffeine oxidase with a half-life of 20 min at 50 degrees C had maximal activity at pH 7.5 and 35 degrees C. The purified caffeine oxidase had strict substrate specificity towards caffeine (K(m) 8.94 microM and V(max) 47.62 U mg protein(-1)) and was not able to oxidize xanthine and hypoxanthine. The enzyme activity was not inhibited by para-chloromercuribenzoic acid, iodoacetamide, n-methylmaleimide, salicylic acid and sodium arsenite indicating the enzyme did not belong to xanthine oxidase family. The enzyme was not affected by Ca(+2), Mg(+2) and Na(+), but was completely inhibited by Co(+2), Cu(+2) and Mn(+2) at 1mM level. The novel caffeine oxidase isolated here from Alcaligenes species CF8 may be useful in biotechnological processes including waste treatment and biosensor development.

  2. Amphetamines, new psychoactive drugs and the monoamine transporter cycle.

    Science.gov (United States)

    Sitte, Harald H; Freissmuth, Michael

    2015-01-01

    In monoaminergic neurons, the vesicular transporters and the plasma membrane transporters operate in a relay. Amphetamine and its congeners target this relay to elicit their actions: most amphetamines are substrates, which pervert the relay to elicit efflux of monoamines into the synaptic cleft. However, some amphetamines act as transporter inhibitors. Both compound classes elicit profound psychostimulant effects, which render them liable to recreational abuse. Currently, a surge of new psychoactive substances occurs on a global scale. Chemists bypass drug bans by ingenuous structural variations, resulting in a rich pharmacology. A credible transport model must account for their distinct mode of action and link this to subtle differences in activity and undesired, potentially deleterious effects.

  3. Amphetamines, new psychoactive drugs and the monoamine transporter cycle

    Science.gov (United States)

    Sitte, Harald H.; Freissmuth, Michael

    2015-01-01

    In monoaminergic neurons, the vesicular transporters and the plasma membrane transporters operate in a relay. Amphetamine and its congeners target this relay to elicit their actions: most amphetamines are substrates, which pervert the relay to elicit efflux of monoamines into the synaptic cleft. However, some amphetamines act as transporter inhibitors. Both compound classes elicit profound psychostimulant effects, which render them liable to recreational abuse. Currently, a surge of new psychoactive substances occurs on a global scale. Chemists bypass drug bans by ingenuous structural variations, resulting in a rich pharmacology. A credible transport model must account for their distinct mode of action and link this to subtle differences in activity and undesired, potentially deleterious effects. PMID:25542076

  4. Real-Time kinetic studies of Bacillus subtilis oxalate decarboxylase and Ceriporiopsis subvermispora oxalate oxidase using a luminescent oxygen sensor

    Directory of Open Access Journals (Sweden)

    Laura Molina

    2014-12-01

    Full Text Available Oxalate decarboxylase (OxDC, an enzyme of the bicupinsuperfamily, catalyzes the decomposition of oxalate into carbondioxide and formate at an optimal pH of 4.3 in the presence ofoxygen. However, about 0.2% of all reactions occur through anoxidase mechanism that consumes oxygen while producing twoequivalents of carbon dioxide and one equivalent of hydrogenperoxide. The kinetics of oxidase activity were studied bymeasuring the consumption of dissolved oxygen over time using a luminescent oxygen sensor. We describe the implementation of and improvements to the oxygen consumption assay. The oxidase activity of wild type OxDC was compared to that of the T165V OxDC mutant, which contains an impaired flexible loop covering the active site. The effects of various carboxylic acid-based buffers on the rate of oxidase activity were also studied. These results were compared to the oxidase activity of oxalate oxidase (OxOx, a similar bicupin enzyme that only carries out oxalate oxidation. Thetemperature dependence of oxidase activity was analyzed, andpreliminary results offer an estimate for the overall activationenergy of the oxidase reaction within OxDC. The data reported here thus provide insights into the mechanism of the oxidase activity of OxDC.

  5. Induction of reactive oxygen species and the potential role of NADPH oxidase in hyperhydricity of garlic plantlets in vitro.

    Science.gov (United States)

    Tian, Jie; Cheng, Yaqi; Kong, Xiangyu; Liu, Min; Jiang, Fangling; Wu, Zhen

    2017-01-01

    Hyperhydricity is a physiological disorder associated with oxidative stress. Reactive oxygen species (ROS) generation in plants is initiated by various enzymatic sources, including plasma membrane-localized nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, cell wall-bound peroxidase (POD), and apoplastic polyamine oxidase (PAO). The origin of the oxidative burst associated with hyperhydricity remains unknown. To investigate the role of NADPH oxidases, POD, and PAO in ROS production and hyperhydricity, exogenous hydrogen peroxide (H2O2) and inhibitors of each ROS-producing enzyme were applied to explore the mechanism of oxidative stress induction in garlic plantlets in vitro. A concentration of 1.5 mM H2O2 increased endogenous ROS production and hyperhydricity occurrence and enhanced the activities of NADPH oxidases, POD, and PAO. During the entire treatment period, NADPH oxidase activity increased continuously, whereas POD and PAO activities exhibited a transient increase and subsequently declined. Histochemical and cytochemical visualization demonstrated that specific inhibitors of each enzyme effectively suppressed ROS accumulation. Moreover, superoxide anion generation, H2O2 content, and hyperhydric shoot frequency in H2O2-stressed plantlets decreased significantly. The NADPH oxidase inhibitor was the most effective at suppressing superoxide anion production. The results suggested that NADPH oxidases, POD, and PAO were responsible for endogenous ROS induction. NADPH oxidase activation might play a pivotal role in the oxidative burst in garlic plantlets in vitro during hyperhydricity.

  6. Oxidative coupling of aromatic pesticide intermediates by a fungal phenol oxidase.

    Science.gov (United States)

    Sjoblad, R D; Bollag, J M

    1977-04-01

    The soil fungus Rhizoctonia praticola produced an enzyme that accumulated in the growth medium and caused the polymerization of phenolic and naphtholic intermediates of various pesticides. The dialyzed crude enzyme was purified by ion-exhange column chromatography with diethylaminoethyl-cellulose, followed by gel filtration with Sephadex G-200. The enzyme, a phenol oxidase, was capable of polymerizing 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, and 4-bromo-2-chlorophenol. 1-Naphthol, 2-naphthol, and some of their derivatives formed oligomers or polymers when incubated with the enzyme, but 4-nitrophenol and 2,4-dinitriphenol were not oxidized. Chlorinated and brominated anilines, which are derivatives of herbicides, were not altered by the phenol oxidase from R. praticola, but 4-methoxyaniline was transformed by the enzyme to 2-amino-5-p-anisidinobenzoquinone-di-p-methoxyphenylimine. The formation of polymeric products was determined by mass spectrometric analysis.

  7. Involvement of NADH Oxidase in Biofilm Formation in Streptococcus sanguinis.

    Directory of Open Access Journals (Sweden)

    Xiuchun Ge

    Full Text Available Biofilms play important roles in microbial communities and are related to infectious diseases. Here, we report direct evidence that a bacterial nox gene encoding NADH oxidase is involved in biofilm formation. A dramatic reduction in biofilm formation was observed in a Streptococcus sanguinis nox mutant under anaerobic conditions without any decrease in growth. The membrane fluidity of the mutant bacterial cells was found to be decreased and the fatty acid composition altered, with increased palmitic acid and decreased stearic acid and vaccenic acid. Extracellular DNA of the mutant was reduced in abundance and bacterial competence was suppressed. Gene expression analysis in the mutant identified two genes with altered expression, gtfP and Idh, which were found to be related to biofilm formation through examination of their deletion mutants. NADH oxidase-related metabolic pathways were analyzed, further clarifying the function of this enzyme in biofilm formation.

  8. Molecular Dynamic Studies of the Complex Polyethylenimine and Glucose Oxidase

    Directory of Open Access Journals (Sweden)

    Beata Szefler

    2016-10-01

    Full Text Available Glucose oxidase (GOx is an enzyme produced by Aspergillus, Penicillium and other fungi species. It catalyzes the oxidation of β-d-glucose (by the molecular oxygen or other molecules, like quinones, in a higher oxidation state to form d-glucono-1,5-lactone, which hydrolyses spontaneously to produce gluconic acid. A coproduct of this enzymatic reaction is hydrogen peroxide (H2O2. GOx has found several commercial applications in chemical and pharmaceutical industries including novel biosensors that use the immobilized enzyme on different nanomaterials and/or polymers such as polyethylenimine (PEI. The problem of GOx immobilization on PEI is retaining the enzyme native activity despite its immobilization onto the polymer surface. Therefore, the molecular dynamic (MD study of the PEI ligand (C14N8_07_B22 and the GOx enzyme (3QVR was performed to examine the final complex PEI-GOx stabilization and the affinity of the PEI ligand to the docking sites of the GOx enzyme. The docking procedure showed two places/regions of major interaction of the protein with the polymer PEI: (LIG1 of −5.8 kcal/mol and (LIG2 of −4.5 kcal/mol located inside the enzyme and on its surface, respectively. The values of enthalpy for the PEI-enzyme complex, located inside of the protein (LIG1 and on its surface (LIG2 were computed. Docking also discovered domains of the GOx protein that exhibit no interactions with the ligand or have even repulsive characteristics. The structural data clearly indicate some differences in the ligand PEI behavior bound at the two places/regions of glucose oxidase.

  9. Molecular Dynamic Studies of the Complex Polyethylenimine and Glucose Oxidase

    Science.gov (United States)

    Szefler, Beata; Diudea, Mircea V.; Putz, Mihai V.; Grudzinski, Ireneusz P.

    2016-01-01

    Glucose oxidase (GOx) is an enzyme produced by Aspergillus, Penicillium and other fungi species. It catalyzes the oxidation of β-d-glucose (by the molecular oxygen or other molecules, like quinones, in a higher oxidation state) to form d-glucono-1,5-lactone, which hydrolyses spontaneously to produce gluconic acid. A coproduct of this enzymatic reaction is hydrogen peroxide (H2O2). GOx has found several commercial applications in chemical and pharmaceutical industries including novel biosensors that use the immobilized enzyme on different nanomaterials and/or polymers such as polyethylenimine (PEI). The problem of GOx immobilization on PEI is retaining the enzyme native activity despite its immobilization onto the polymer surface. Therefore, the molecular dynamic (MD) study of the PEI ligand (C14N8_07_B22) and the GOx enzyme (3QVR) was performed to examine the final complex PEI-GOx stabilization and the affinity of the PEI ligand to the docking sites of the GOx enzyme. The docking procedure showed two places/regions of major interaction of the protein with the polymer PEI: (LIG1) of −5.8 kcal/mol and (LIG2) of −4.5 kcal/mol located inside the enzyme and on its surface, respectively. The values of enthalpy for the PEI-enzyme complex, located inside of the protein (LIG1) and on its surface (LIG2) were computed. Docking also discovered domains of the GOx protein that exhibit no interactions with the ligand or have even repulsive characteristics. The structural data clearly indicate some differences in the ligand PEI behavior bound at the two places/regions of glucose oxidase. PMID:27801788

  10. Molecular Dynamic Studies of the Complex Polyethylenimine and Glucose Oxidase.

    Science.gov (United States)

    Szefler, Beata; Diudea, Mircea V; Putz, Mihai V; Grudzinski, Ireneusz P

    2016-10-27

    Glucose oxidase (GOx) is an enzyme produced by Aspergillus, Penicillium and other fungi species. It catalyzes the oxidation of β-d-glucose (by the molecular oxygen or other molecules, like quinones, in a higher oxidation state) to form d-glucono-1,5-lactone, which hydrolyses spontaneously to produce gluconic acid. A coproduct of this enzymatic reaction is hydrogen peroxide (H₂O₂). GOx has found several commercial applications in chemical and pharmaceutical industries including novel biosensors that use the immobilized enzyme on different nanomaterials and/or polymers such as polyethylenimine (PEI). The problem of GOx immobilization on PEI is retaining the enzyme native activity despite its immobilization onto the polymer surface. Therefore, the molecular dynamic (MD) study of the PEI ligand (C14N8_07_B22) and the GOx enzyme (3QVR) was performed to examine the final complex PEI-GOx stabilization and the affinity of the PEI ligand to the docking sites of the GOx enzyme. The docking procedure showed two places/regions of major interaction of the protein with the polymer PEI: (LIG1) of -5.8 kcal/mol and (LIG2) of -4.5 kcal/mol located inside the enzyme and on its surface, respectively. The values of enthalpy for the PEI-enzyme complex, located inside of the protein (LIG1) and on its surface (LIG2) were computed. Docking also discovered domains of the GOx protein that exhibit no interactions with the ligand or have even repulsive characteristics. The structural data clearly indicate some differences in the ligand PEI behavior bound at the two places/regions of glucose oxidase.

  11. 1-Aminocyclopropane-1-Carboxylate Oxidase Activity Limits Ethylene Biosynthesis in Rumex palustris during Submergence

    Science.gov (United States)

    Vriezen, Wim H.; Hulzink, Raymond; Mariani, Celestina; Voesenek, Laurentius A.C.J.

    1999-01-01

    Submergence strongly stimulates petiole elongation in Rumex palustris, and ethylene accumulation initiates and maintains this response in submerged tissues. cDNAs from R. palustris corresponding to a 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene (RP-ACO1) were isolated from elongating petioles and used to study the expression of the corresponding gene. An increase in RP-ACO1 messenger was observed in the petioles and lamina of elongating leaves 2 h after the start of submergence. ACC oxidase enzyme activity was measured in homogenates of R. palustris shoots, and a relevant increase was observed within 12 h under water with a maximum after 24 h. We have shown previously that the ethylene production rate of submerged shoots does not increase significantly during the first 24 h of submergence (L.A.C.J. Voesenek, M. Banga, R.H. Thier, C.M. Mudde, F.M. Harren, G.W.M. Barendse, C.W.P.M. Blom [1993] Plant Physiol 103: 783–791), suggesting that under these conditions ACC oxidase activity is inhibited in vivo. We found evidence that this inhibition is caused by a reduction of oxygen levels. We hypothesize that an increased ACC oxidase enzyme concentration counterbalances the reduced enzyme activity caused by low oxygen concentration during submergence, thus sustaining ethylene production under these conditions. Therefore, ethylene biosynthesis seems to be limited at the level of ACC oxidase activity rather than by ACC synthase in R. palustris during submergence. PMID:10482674

  12. Urate oxidase purification by salting-in crystallization: towards an alternative to chromatography.

    Directory of Open Access Journals (Sweden)

    Marion Giffard

    Full Text Available BACKGROUND: Rasburicase (Fasturtec® or Elitek®, Sanofi-Aventis, the recombinant form of urate oxidase from Aspergillus flavus, is a therapeutic enzyme used to prevent or decrease the high levels of uric acid in blood that can occur as a result of chemotherapy. It is produced by Sanofi-Aventis and currently purified via several standard steps of chromatography. This work explores the feasibility of replacing one or more chromatography steps in the downstream process by a crystallization step. It compares the efficacy of two crystallization techniques that have proven successful on pure urate oxidase, testing them on impure urate oxidase solutions. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigate the possibility of purifying urate oxidase directly by crystallization from the fermentation broth. Based on attractive interaction potentials which are known to drive urate oxidase crystallization, two crystallization routes are compared: a by increased polymer concentration, which induces a depletion attraction and b by decreased salt concentration, which induces attractive interactions via a salting-in effect. We observe that adding polymer, a very efficient way to crystallize pure urate oxidase through the depletion effect, is not an efficient way to grow crystals from impure solution. On the other hand, we show that dialysis, which decreases salt concentration through its strong salting-in effect, makes purification of urate oxidase from the fermentation broth possible. CONCLUSIONS: The aim of this study is to compare purification efficacy of two crystallization methods. Our findings show that crystallization of urate oxidase from the fermentation broth provides purity comparable to what can be achieved with one chromatography step. This suggests that, in the case of urate oxidase, crystallization could be implemented not only for polishing or concentration during the last steps of purification, but also as an initial capture step, with minimal

  13. Lysyl oxidase in cancer research.

    Science.gov (United States)

    Perryman, Lara; Erler, Janine T

    2014-01-01

    Metastasis is the main reason for cancer-associated deaths and therapies are desperately needed to target the progression of cancer. Lysyl oxidase (LOX) plays a pivotal role in cancer progression, including metastasis, and is therefore is an attractive therapeutic target. In this review we will breakdown the process of cancer progression and the various roles that LOX plays has in the advancement of cancer. We will highlight why LOX is an exciting therapeutic target for the future.

  14. Process requirements of galactose oxidase catalyzed oxidation of alcohols

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard; R. Birmingham, William; Rehn, Gustav

    2015-01-01

    biocatalyst for the oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. However, GOase requires a number of additives to sustain its catalytic function, such as the enzyme catalase for degradation of the byproduct hydrogen peroxide as well as single......-electron oxidants to reactivate the enzyme upon loss of the amino acid radical in its active site. In this work, the addition of catalase, single-electron oxidants, and copper ions was investigated systematically in order to find the minimum concentrations required to obtain a fully active GOase. Furthermore......, it was found that the concentration and type of buffer is essential for the activity of GOase, which was significantly more active in sodium phosphate buffer than in other buffers investigated. Enzyme stability and oxygen requirements are of crucial importance for the implementation of oxidase based processes...

  15. Purification and spectroscopic studies on catechol oxidase from lemon balm (Melissa officinalis).

    Science.gov (United States)

    Rompel, Annette; Büldt-Karentzopoulos, Klaudia; Molitor, Christian; Krebs, Bernt

    2012-09-01

    A catechol oxidase from lemon balm (Melissa officinalis) moCO which only catalyzes the oxidation of catechols to quinones without hydroxylating tyrosine was purified. The molecular mass of the M. officinalis enzyme of 39,370 Da was obtained by MALDI mass spectrometry and the isoelectric point was determined to be 3.4. Addition of 2 eq. H(2)O(2) to the enzyme leads to oxy catechol oxidase. In the UV/Vis spectrum two new absorption bands occur at 343 nm (ε=8510 M(-1)cm(-1)) and 580 nm (ε=580 M(-1)cm(-1)) due to O(2)(2-)Cu (II) charge transfer transitions in accordance with the oxy forms of other type 3 copper proteins. The N-terminal sequence has been determined by Edman degradation to NPVQAPELDKCGTAT, exhibiting a proline at the second and sixth position conserved in other polyphenol oxidases. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Crystallization of recombinant 1-amino cyclo propane-1-carboxylate (Acc) oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, L.; Arni, R.K. [UNESP, Sao Jose do Rio Preto, SP (Brazil). Dept. de Fisica; Dilley, D. [Michigan State Univ., East Lansing, MI (United States). Dept. of Biophysics

    1996-12-31

    Full text. Ethylene is an important harmone in plant biology because it activates gene expression with consequences at all phases of plant growth and development spanning seed germination to fruit ripening and senesense of plant organs. In climacteric fruits, the sharp increase in ethylene production at the onset of ripening is throught to trigger the changes in colour, aroma, texture and flavour. The final step in ethylene biosynthesis is catalyzed by ACC oxidase. Biothechnological methods have been used to inhibit ethylene biosynthesis and ripening in tomato by down-regulating ACC synthase and ACC oxidase gene expression using the antisense RNA strategy. A similar goal has been achieved by overexpressing a bacterial ACC deaminase or a viral-S-adenosylmethionine hydrolase gene, which reduces the availability of the ethylene precursors., ACC and S-adenosylmethionine, respectively. C0{sub 2} at concentrations commonly found in the intracellular space of plant tissues is required to active ACC oxidase to produce ethylene and can elevate enzyme activity 20-fold in a concentration dependent manner. Consequently, the intracellular ethylene level is modulated from low inactive levels when C0{sub 2} is not limiting and this may alter gene expression. ACC oxidase undergoes catalytic inactivation as the reaction to make ethylene procedes and this too may involve CO{sub 2}. It has been suggested that CO{sub 2}acts as a modulator of ACC oxidase activity and therby helps regulate ethylene levels in the cell and thus may explain many ethylene related phenomena in plant biology. CO{sub 2} is know to affect O{sub 2} binding in hemoglobin and ribulose bisphosphate carboxylase-oxygenase (Rubisco). Catalytic inactivation is a common phenomena in enzyme turnover, ACC oxidase is a Fe{sup +2}/ascorbate requiring enzyme and this makes it a prime candidate for metal ion oxidation-based inactivation. Charentais melon with an antisense ACC oxidase cDNA. A trangenic line exhibits reduction

  17. Effects of Yulangsan polysaccharide on monoamine neurotransmitters, adenylate cyclase activity and brain-derived neurotrophic factor expression in a mouse model of depression induced by unpredictable chronic mild stress

    Institute of Scientific and Technical Information of China (English)

    Shuang Liang; Renbin Huang; Xing Lin; Jianchun Huang; Zhongshi Huang; Huagang Liu

    2012-01-01

    The present study established a mouse model of depression induced by unpredictable chronic mild stress. The model mice were treated with Yulangsan polysaccharide (YLSPS; 150, 300 and 600 mg/kg) for 21 days, and compared with fluoxetine-treated and normal control groups. Enzyme-linked immunosorbent assay, radioimmunity and immunohistochemical staining showed that following treatment with YLSPS (300 and 600 mg/kg), monoamine neurotransmitter levels, prefrontal cortex adenylate cyclase activity and hippocampal brain-derived neurotrophic factor expression were significantly elevated, and depression-like behaviors were improved. Open-field and novelty-suppressed feeding tests showed that mouse activity levels were increased and feeding latency was shortened following treatment. Our results indicate that YLSPS inhibits depression by upregulating monoamine neurotransmitters, prefrontal cortex adenylate cyclase activity and hippocampal brain-derived neurotrophic factor expression.

  18. Gold Nanoparticles Like A Matrix For Covalent Immobilization Of Cholesterol Oxidase – Application For Biosensing

    Directory of Open Access Journals (Sweden)

    Wojnarowska R.

    2015-09-01

    Full Text Available Gold nanoparticles are emerging as promising agents for various areas of material science as well as nanotechnology, electronics and medicine. The interest in this material is provided due to its unique optical, electronic and molecular-recognition properties. This paper presents results of preparation, characterization and biofunctionalization of gold nanoparticles. Nanoparticles have been conjugated with the cholesterol oxidase enzyme in order to prepare the active element for biosensors. Cholesterol oxidase is one of the most important analytical enzyme, used for cholesterol assay in clinical diagnostics, and there is still a necessity in improvement of existing analytical techniques, including bio-nanotechnological approaches based on modern nanosystems. The prepared bio-nanosystem was characterized by the enzyme activity test. Obtained results showed a stable binding of the enzyme with nanoparticles and preserved the bioactivity approves which gives possibility to use the prepared bio-nanosystems for analytical purposes.

  19. Modification of flavin adenine dinucleotide in alcohol oxidase of the yeast Hansenula polymorpha

    NARCIS (Netherlands)

    Bystrykh, Leonid V.; Dijkhuizen, Lubbert; Harder, Willem

    1991-01-01

    Alcohol oxidase, a major peroxisomal protein of methanol-utilizing yeasts, may possess two different forms of flavin adenine dinucleotide, classical FAD and so-called modified FAD (mFAD). Conversion of FAD into mFAD was observed both in purified preparations of the enzyme and in cells grown in batch

  20. Lysyl Oxidase Plays a Critical Role in Endothelial Cell Stimulation to Drive Tumor Angiogenesis

    DEFF Research Database (Denmark)

    Baker, Ann-Marie; Bird, Demelza; Welti, Jonathan C

    2013-01-01

    Identification of key molecules that drive angiogenesis is critical for the development of new modalities for the prevention of solid tumor progression. Using multiple models of colorectal cancer, we show that activity of the extracellular matrix-modifying enzyme lysyl oxidase (LOX) is essential ...

  1. Isolation of mutants of Hansenula polymorpha defective in the assembly of octameric alcohol oxidase

    NARCIS (Netherlands)

    Dijk, Ralf van; Lahchev, Kancho L.; Kram, Anita M.; Klei, Ida J. van der; Veenhuis, Marten

    2002-01-01

    Alcohol oxidase (AO) is a peroxisomal enzyme that catalyses the first step in methanol metabolism in yeast. Monomeric, inactive AO protein is synthesised in the cytosol and subsequently imported into peroxisomes, where the enzymatically active, homo-octameric form is found. The mechanisms involved i

  2. Are colorimetric assays appropriate for measuring phenol oxidase activity in peat soils?

    Science.gov (United States)

    Magdalena M. Wiedermann; Evan S. Kane; Timothy J. Veverica; Erik A. Lilleskov

    2017-01-01

    The activity of extracellular phenol oxidases is believed to play a critical role in decomposition processes in peatlands. The water logged, acidic conditions, and recalcitrant litter from the peatland vegetation, lead to exceptionally high phenolics in the peat. In order to quantify the activity of oxidative enzymes involved in the modification and break down of...

  3. Placental NAD(P)H oxidase mediated superoxide generation in early pregnancy.

    NARCIS (Netherlands)

    Raijmakers, M.; Burton, G.J.; Jauniaux, E.; Seed, P.T.; Peters, W.H.M.; Steegers, E.A.P.; Poston, L.

    2006-01-01

    Early placental development is characterised by rapid cell differentiation and migration, matrix remodelling and angiogenesis. The enzyme NAD(P)H oxidase is a major source of superoxide anions implicated in signalling pathways regulating these processes in other systems. It is also thought to be

  4. The caa(3) terminal oxidase of Bacillus stearothermophilus - Transient spectroscopy of electron transfer and ligand binding

    NARCIS (Netherlands)

    Giuffre, A; DItri, E; Giannini, S; Brunori, M; UbbinkKok, T; Konings, WN; Antonini, G

    1996-01-01

    The thermophilic bacterium Bacillus stearothermophilus possesses a caa(3)-type terminal oxidase, which was previously purified (De Vrij, W., Heyne, R. I. HL, and Konings, W. N. (1989) Ear. J. Biochem. 178, 763-770). We have carried out extensive kinetic experiments on the purified enzyme by stopped-

  5. The reaction of Pseudomonas aeurginosa cytochrome c oxidase with sodium metabisulphite.

    Science.gov (United States)

    Parr, S R; Wilson, M T; Greenwood, C

    1974-04-01

    Spectrophotometric evidence is presented for the formation of a complex between metabisulphite and reduced Pseudomonas aeruginosa cytochrome c oxidase. The effects of metabisulphite on the recombination of CO with the reduced enzyme are discussed in terms of alternate binding sites for S(2)O(5) (2-) and CO.

  6. Discovery and characterization of a putrescine oxidase from Rhodococcus erythropolis NCIMB 11540

    NARCIS (Netherlands)

    van Hellemond, Erik W.; van Dijk, Marianne; Heuts, Dominic P. H. M.; Janssen, Dick B.; Fraaije, Marco W.

    2008-01-01

    A gene encoding a putrescine oxidase (PuORh, EC 1.4.3.10) was identified from the genome of Rhodococcus erythropolis NCIMB 11540. The gene was cloned in the pBAD vector and overexpressed at high levels in Escherichia coli. The purified enzyme was shown to be a soluble dimeric flavoprotein consisting

  7. Discovery and characterization of a putrescine oxidase from Rhodococcus erythropolis NCIMB 11540

    NARCIS (Netherlands)

    van Hellemond, Erik W.; van Dijk, Marianne; Heuts, Dominic P. H. M.; Janssen, Dick B.; Fraaije, Marco W.

    A gene encoding a putrescine oxidase (PuORh, EC 1.4.3.10) was identified from the genome of Rhodococcus erythropolis NCIMB 11540. The gene was cloned in the pBAD vector and overexpressed at high levels in Escherichia coli. The purified enzyme was shown to be a soluble dimeric flavoprotein consisting

  8. Tissue Printing to Visualize Polyphenol Oxidase and Peroxidase in Vegetables, Fruits, and Mushrooms

    Science.gov (United States)

    Melberg, Amanda R.; Flurkey, William H.; Inlow, Jennifer K.

    2009-01-01

    A simple tissue-printing procedure to determine the tissue location of the endogenous enzymes polyphenol oxidase and peroxidase in a variety of vegetables, fruits, and mushrooms is described. In tissue printing, cell contents from the surface of a cut section of the tissue are transferred to an adsorptive surface, commonly a nitrocellulose…

  9. Kinetic mechanism of vanillyl-alcohol oxidase with short-chain 4-alkylphenols

    NARCIS (Netherlands)

    Fraaije, Marco W.; Heuvel, Robert H.H. van den; Roelofs, Jules C.A.A.; Berkel, Willem J.H. van

    1998-01-01

    The kinetic mechanism of vanillyl-alcohol oxidase with 4-methylphenol, 4-ethylphenol, 4-propylphenol and their Cα-deuterated analogs has been studied at pH 7.5 and 25°C. Conversion of 4-methylphenol is extremely slow (0.005 s-1) while the enzyme is largely in the reduced form during turnover.

  10. Isolation of liver aldehyde oxidase containing fractions from different animals and determination of kinetic parameters for benzaldehyde

    Directory of Open Access Journals (Sweden)

    Kadam R

    2008-01-01

    Full Text Available Aldehyde oxidase activity containing fractions from rabbit, guinea pig, rat and mouse livers were obtained by heat treatment and ammonium sulfate precipitation. Aldehyde oxidase activity was observed in rabbit and guinea pig livers, while aldehyde oxidase activity was absent in rat and mouse liver fractions. Enzyme kinetic parameters, K m and V max , were determined for the oxidation of benzaldehyde to benzoic acid by rabbit and guinea pig liver fractions, by spectrophotometric method, with potassium ferricyanide as the electron acceptor. The K m values obtained for both animal liver fractions were in the range of 10.3-19.1 µM.

  11. Molecular Basis of Reduced Pyridoxine 5′-Phosphate Oxidase Catalytic Activity in Neonatal Epileptic Encephalopathy Disorder*

    OpenAIRE

    2009-01-01

    Mutations in pyridoxine 5′-phosphate oxidase are known to cause neonatal epileptic encephalopathy. This disorder has no cure or effective treatment and is often fatal. Pyridoxine 5′-phosphate oxidase catalyzes the oxidation of pyridoxine 5′-phosphate to pyridoxal 5′-phosphate, the active cofactor form of vitamin B6 required by more than 140 different catalytic activities, including enzymes involved in amino acid metabolism and biosynthesis of neurotransmitters. Our aim is to elucidate the mec...

  12. Modified Active Site Coordination in a Clinical Mutant of Sulfite Oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Doonan, C.J.; Wilson, H.L.; Rajagopalan, K.V.; Garrett, R.M.; Bennett, B.; Prince, R.C.; George, G.N.

    2009-06-02

    The molybdenum site of the Arginine 160 {yields} Glutamine clinical mutant of the physiologically vital enzyme sulfite oxidase has been investigated by a combination of X-ray absorption spectroscopy and density functional theory calculations. We conclude that the mutant enzyme has a six-coordinate pseudo-octahedral active site with coordination of Glutamine O{sup {epsilon}} to molybdenum. This contrasts with the wild-type enzyme which is five-coordinate with approximately square-based pyramidal geometry. This difference in the structure of the molybdenum site explains many of the properties of the mutant enzyme which have previously been reported.

  13. Graphene modified electrospun poly(vinyl alcohol nanofibrous membranes for glucose oxidase immobilization

    Directory of Open Access Journals (Sweden)

    C. M. Wu

    2014-08-01

    Full Text Available In this study, poly(vinyl alcohol (PVA/Glucose oxidase (GOx/graphene biocomposite membranes were prepared using an electrospinning technique and used for enzyme immobilization. The PVA/GOx/graphene membrane’s morphology was examined by scanning electron microscopy (SEM and transmission electron microscopy (TEM, while its electrochemical sensitivity was studied by chronoamperometry. Kinetic parameters were determined to clarify the role of graphene in enzyme immobilization, while a spectrophotometric assay was used to quantify the active enzyme. The results indicated that the presence of graphene helps to stabilize the enzyme’s conformation, facilitate the catalytic reaction, and increase the survivability of the enzyme.

  14. The effects of two chronic intermittent stressors on brain monoamines.

    Science.gov (United States)

    Campmany, L; Pol, O; Armario, A

    1996-03-01

    The effects of chronic exposure (27 days) to two different stressors on brain monoaminergic activity was studied in adult male rats. The stressors used were restraint in tubes (RES) and immobilization in wooden boards (IMO). Both chronically stressed and stress naive (control) rats were subjected to 0, 15, and 60 min of the same stressor to which they were chronically exposed. Previous chronic exposure to either RES or IMO significantly reduced ACTH response to the same stressor. Monoaminergic response to these stressors was studied by measuring the levels of noradrenaline (NA), serotonin (5-HT) and their metabolites: 3-methoxy,4-hydroxyphenyletileneglycol sulfate (MHPG-SO4) and 5-hydroxyindoleacetic acid (5-HIAA), respectively. The regions studied were: pons plus medulla, midbrain, hypothalamus, hippocampus, and frontal cortex. Previous chronic exposure to the stressors induced only few changes in the resting levels of the monoamines and their metabolites. In addition, monoaminergic response to the same stressor to which they were chronically exposed was always similar in control and chronically stressed rats. These data indicate that brain NA and 5-HT metabolism is less sensitive than ACTH to the process of habituation to a repeated stressor, at least in the gross areas of the brain analyzed in the present study.

  15. Activation of thiamin diphosphate in enzymes.

    Science.gov (United States)

    Hübner, G; Tittmann, K; Killenberg-Jabs, M; Schäffner, J; Spinka, M; Neef, H; Kern, D; Kern, G; Schneider, G; Wikner, C; Ghisla, S

    1998-06-29

    Activation of the coenzyme ThDP was studied by measuring the kinetics of deprotonation at the C2 carbon of thiamin diphosphate in the enzymes pyruvate decarboxylase, transketolase, pyruvate dehydrogenase complex, pyruvate oxidase, in site-specific mutant enzymes and in enzyme complexes containing coenzyme analogues by proton/deuterium exchange detected by 1H-NMR spectroscopy. The respective deprotonation rate constant is above the catalytic constant in all enzymes investigated. The fast deprotonation requires the presence of an activator in pyruvate decarboxylase from yeast, showing the allosteric regulation of this enzyme to be accomplished by an increase in the C2-H dissociation rate of the enzyme-bound thiamin diphosphate. The data of the thiamin diphosphate analogues and of the mutant enzymes show the N1' atom and the 4'-NH2 group to be essential for the activation of the coenzyme and a conserved glutamate involved in the proton abstraction mechanism of the enzyme-bound thiamin diphosphate.

  16. Marked and variable inhibition by chemical fixation of cytochrome oxidase and succinate dehydrogenase in single motoneurons

    Science.gov (United States)

    Chalmers, G. R.; Edgerton, V. R.

    1989-01-01

    The effect of tissue fixation on succinate dehydrogenase and cytochrome oxidase activity in single motoneurons of the rat was demonstrated using a computer image processing system. Inhibition of enzyme activity by chemical fixation was variable, with some motoneurons being affected more than others. It was concluded that quantification of enzymatic activity in chemically fixed tissue provides an imprecise estimate of enzyme activities found in fresh-frozen tissues.

  17. Antidepressant stimulation of CDP-diacylglycerol synthesis does not require monoamine reuptake inhibition

    Directory of Open Access Journals (Sweden)

    Aboukhatwa Marwa A

    2010-01-01

    Full Text Available Abstract Background Recent studies demonstrate that diverse antidepressant agents increase the cellular production of the nucleolipid CDP-diacylglycerol and its synthetic derivative, phosphatidylinositol, in depression-relevant brain regions. Pharmacological blockade of downstream phosphatidylinositide signaling disrupted the behavioral antidepressant effects in rats. However, the nucleolipid responses were resistant to inhibition by serotonin receptor antagonists, even though antidepressant-facilitated inositol phosphate accumulation was blocked. Could the neurochemical effects be additional to the known effects of the drugs on monoamine transmitter transporters? To examine this question, we tested selected agents in serotonin-depleted brain tissues, in PC12 cells devoid of serotonin transporters, and on the enzymatic activity of brain CDP-diacylglycerol synthase - the enzyme that catalyzes the physiological synthesis of CDP-diacylglycerol. Results Imipramine, paroxetine, and maprotiline concentration-dependently increased the levels of CDP-diacylglycerol and phosphatidylinositides in PC12 cells. Rat forebrain tissues depleted of serotonin by pretreatment with p-chlorophenylalanine showed responses to imipramine or maprotiline that were comparable to respective responses from saline-injected controls. With fluoxetine, nucleolipid responses in the serotonin-depleted cortex or hippocampus were significantly reduced, but not abolished. Each drug significantly increased the enzymatic activity of CDP-diacylglycerol synthase following incubations with cortical or hippocampal brain tissues. Conclusion Antidepressants probably induce the activity of CDP-diacylglycerol synthase leading to increased production of CDP-diacylglycerol and facilitation of downstream phosphatidylinositol synthesis. Phosphatidylinositol-dependent signaling cascades exert diverse salutary effects in neural cells, including facilitation of BDNF signaling and neurogenesis. Hence

  18. Myeloid-derived suppressor cells modulate immune responses independently of NADPH oxidase in the ovarian tumor microenvironment in mice.

    Directory of Open Access Journals (Sweden)

    Heidi E Godoy

    Full Text Available The phagocyte NADPH oxidase generates superoxide anion and downstream reactive oxidant intermediates in response to infectious threat, and is a critical mediator of antimicrobial host defense and inflammatory responses. Myeloid-derived suppressor cells (MDSCs are a heterogeneous population of immature myeloid cells that are recruited by cancer cells, accumulate locally and systemically in advanced cancer, and can abrogate anti-tumor immunity. Prior studies have implicated the phagocyte NADPH oxidase as being an important component promoting MDSC accumulation and immunosuppression in cancer. We therefore used engineered NADPH oxidase-deficient (p47 (phox-/- mice to delineate the role of this enzyme complex in MDSC accumulation and function in a syngeneic mouse model of epithelial ovarian cancer. We found that the presence of NADPH oxidase did not affect tumor progression. The accumulation of MDSCs locally and systemically was similar in tumor-bearing wild-type (WT and p47 (phox-/- mice. Although MDSCs from tumor-bearing WT mice had functional NADPH oxidase, the suppressive effect of MDSCs on ex vivo stimulated T cell proliferation was NADPH oxidase-independent. In contrast to other tumor-bearing mouse models, our results show that MDSC accumulation and immunosuppression in syngeneic epithelial ovarian cancer is NADPH oxidase-independent. We speculate that factors inherent to the tumor, tumor microenvironment, or both determine the specific requirement for NADPH oxidase in MDSC accumulation and function.

  19. Stepwise engineering of a Pichia pastoris D-amino acid oxidase whole cell catalyst

    Directory of Open Access Journals (Sweden)

    Speight Robert

    2010-04-01

    Full Text Available Abstract Background Trigonopsis variabilis D-amino acid oxidase (TvDAO is a well characterized enzyme used for cephalosporin C conversion on industrial scale. However, the demands on the enzyme with respect to activity, operational stability and costs also vary with the field of application. Processes that use the soluble enzyme suffer from fast inactivation of TvDAO while immobilized oxidase preparations raise issues related to expensive carriers and catalyst efficiency. Therefore, oxidase preparations that are more robust and active than those currently available would enable a much broader range of economically viable applications of this enzyme in fine chemical syntheses. A multi-step engineering approach was chosen here to develop a robust and highly active Pichia pastoris TvDAO whole-cell biocatalyst. Results As compared to the native T. variabilis host, a more than seven-fold enhancement of the intracellular level of oxidase activity was achieved in P. pastoris through expression optimization by codon redesign as well as efficient subcellular targeting of the enzyme to peroxisomes. Multi copy integration further doubled expression and the specific activity of the whole cell catalyst. From a multicopy production strain, about 1.3 × 103 U/g wet cell weight (wcw were derived by standard induction conditions feeding pure methanol. A fed-batch cultivation protocol using a mixture of methanol and glycerol in the induction phase attenuated the apparent toxicity of the recombinant oxidase to yield final biomass concentrations in the bioreactor of ≥ 200 g/L compared to only 117 g/L using the standard methanol feed. Permeabilization of P. pastoris using 10% isopropanol yielded a whole-cell enzyme preparation that showed 49% of the total available intracellular oxidase activity and was notably stabilized (by three times compared to a widely used TvDAO expressing Escherichia coli strain under conditions of D-methionine conversion using vigorous

  20. Pectic enzymes

    NARCIS (Netherlands)

    Benen, J.A.E.; Voragen, A.G.J.; Visser, J.

    2003-01-01

    The pectic enzymes comprise a diverse group of enzymes. They consist of main-chain depolymerases and esterases active on methyl- and acetylesters of galacturonosyl uronic acid residues. The depolymerizing enzymes comprise hydrolases as wel as lyases

  1. Pectic enzymes

    NARCIS (Netherlands)

    Benen, J.A.E.; Voragen, A.G.J.; Visser, J.

    2003-01-01

    The pectic enzymes comprise a diverse group of enzymes. They consist of main-chain depolymerases and esterases active on methyl- and acetylesters of galacturonosyl uronic acid residues. The depolymerizing enzymes comprise hydrolases as wel as lyases

  2. Spatiotemporal localization of D-amino acid oxidase and D-aspartate oxidases during development in Caenorhabditis elegans.

    Science.gov (United States)

    Saitoh, Yasuaki; Katane, Masumi; Kawata, Tomonori; Maeda, Kazuhiro; Sekine, Masae; Furuchi, Takemitsu; Kobuna, Hiroyuki; Sakamoto, Taro; Inoue, Takao; Arai, Hiroyuki; Nakagawa, Yasuhito; Homma, Hiroshi

    2012-05-01

    Recent investigations have shown that a variety of D-amino acids are present in living organisms and that they possibly play important roles in physiological functions in the body. D-Amino acid oxidase (DAO) and D-aspartate oxidase (DDO) are degradative enzymes stereospecific for D-amino acids. They have been identified in various organisms, including mammals and the nematode Caenorhabditis elegans, although the significance of these enzymes and the relevant functions of D-amino acids remain to be elucidated. In this study, we investigated the spatiotemporal localization of C. elegans DAO and DDOs (DDO-1, DDO-2, and DDO-3) and measured the levels of several D- and L-amino acids in wild-type C. elegans and four mutants in which each gene for DAO and the DDOs was partially deleted and thereby inactivated. Furthermore, several phenotypes of these mutant strains were characterized. The results reported in this study indicate that C. elegans DAO and DDOs are involved in egg-laying events and the early development of C. elegans. In particular, DDOs appear to play important roles in the development and maturation of germ cells. This work provides novel and useful insights into the physiological functions of these enzymes and D-amino acids in multicellular organisms.

  3. Enzyme conductometric biosensor for maltose determination

    OpenAIRE

    2009-01-01

    Aim. To develop enzyme conductometric biosensor for maltose determination. Methods. A conductometric transducer consisting of two gold pairs of electrodes was applied. Three-enzyme membrane (glucose oxidase, mutarotase, -glucosidase) immobilized on the surface of the conductometric transducer was used as a bioselective element. Results. A linear range of maltose conductometric biosensor was from 0,002 mM to 1 mM for glucose and maltose detection. The time of maltose analysis in solution was 1...

  4. Enzyme assays.

    Science.gov (United States)

    Reymond, Jean-Louis; Fluxà, Viviana S; Maillard, Noélie

    2009-01-07

    Enzyme assays are analytical tools to visualize enzyme activities. In recent years a large variety of enzyme assays have been developed to assist the discovery and optimization of industrial enzymes, in particular for "white biotechnology" where selective enzymes are used with great success for economically viable, mild and environmentally benign production processes. The present article highlights the aspects of fluorogenic and chromogenic substrates, sensors, and enzyme fingerprinting, which are our particular areas of interest.

  5. Mechanisms for suppressing NADPH oxidase in the vascular wall

    Directory of Open Access Journals (Sweden)

    Gregory J Dusting

    2005-03-01

    Full Text Available Oxidative stress underlies many forms of vascular disease as well as tissue injury following ischemia and reperfusion. The major source of oxidative stress in the artery wall is an NADPH oxidase. This enzyme complex as expressed in vascular cells differs from that in phagocytic leucocytes both in biochemical structure and functions. The crucial flavin-containing catalytic subunits, Nox1 and Nox4, are not found in leucocytes, but are highly expressed in vascular cells and upregulated with vascular remodeling, such as that found in hypertension and atherosclerosis. The difference in catalytic subunits offers the opportunity to develop "vascular specific" NADPH oxidase inhibitors that do not compromise the essential physiological signaling and phagocytic functions carried out by reactive oxygen and nitrogen species. Nitric oxide and targeted inhibitors of NADPH oxidase that block the source of oxidative stress in the vasculature are more likely to prevent the deterioration of vascular function that leads to stroke and heart attack, than are conventional antioxidants. The roles of Nox isoforms in other inflammatory conditions are yet to be explored.

  6. The terminal oxidases of Paracoccus denitrificans

    OpenAIRE

    de Gier, Jan-Willem L.; Lübben, Mathias; Reijnders, Willem N.M.; Tipker, Corinne A.; Slotboom, Dirk-Jan; Van Spanning, Rob J. M.; Stouthamer, Adriaan H.; van der Oost, John

    1994-01-01

    Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit I of the aa3-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to complement a double mutant (ΔctaDI, ΔctaDII), indicating that they are isoforms of subunit I of the aa3-type oxidase. The genomic locus of a quinol oxidase has been isolated: cyoABC. This protohaem...

  7. NADPH Oxidase as a Therapeutic Target for Neuroprotection against Ischaemic Stroke: Future Perspectives

    Directory of Open Access Journals (Sweden)

    Carli L. Roulston

    2013-04-01

    Full Text Available Oxidative stress caused by an excess of reactive oxygen species (ROS is known to contribute to stroke injury, particularly during reperfusion, and antioxidants targeting this process have resulted in improved outcomes experimentally. Unfortunately these improvements have not been successfully translated to the clinical setting. Targeting the source of oxidative stress may provide a superior therapeutic approach. The NADPH oxidases are a family of enzymes dedicated solely to ROS production and pre-clinical animal studies targeting NADPH oxidases have shown promising results. However there are multiple factors that need to be considered for future drug development: There are several homologues of the catalytic subunit of NADPH oxidase. All have differing physiological roles and may contribute differentially to oxidative damage after stroke. Additionally, the role of ROS in brain repair is largely unexplored, which should be taken into consideration when developing drugs that inhibit specific NADPH oxidases after injury. This article focuses on the current knowledge regarding NADPH oxidase after stroke including in vivo genetic and inhibitor studies. The caution required when interpreting reports of positive outcomes after NADPH oxidase inhibition is also discussed, as effects on long term recovery are yet to be investigated and are likely to affect successful clinical translation.

  8. Cytochrome oxidase as an indicator of ice storage and frozen storage

    DEFF Research Database (Denmark)

    Godiksen, Helene; Jessen, Flemming

    2001-01-01

    The potential of cytochrome oxidase as an indicator of ice storage and frozen storage of fish was investigated. Optimal assay conditions for cytochrome oxidase in a crude homogenate from cod muscle were studied. Maximal cytochrome oxidase activity was found at pH 6.5-7.5 and an assay temperature...... of 30 degreesC. Maximal activation by Triton X-100 was obtained in a range of 0.62-1.25 mM Triton X-100. The specificity of the assay was high, as cytochrome oxidase was inhibited 98% by 33 muM of the specific inhibitor sodium azide. The coefficient of variation of cytochrome oxidase activity...... in different cods was 21%, and the coefficient of variation of different analyses on the same homogenate was 5%. It was shown that ice storage of muscle samples before they were frozen and thawed resulted in a major freezing-induced activation of cytochrome oxidase activity. The enzyme may therefore be used...

  9. Involvement of phospholipase D and NADPH-oxidase in salicylic acid signaling cascade.

    Science.gov (United States)

    Kalachova, Tetiana; Iakovenko, Oksana; Kretinin, Sergii; Kravets, Volodymyr

    2013-05-01

    Salicylic acid is associated with the primary defense responses to biotic stress and formation of systemic acquired resistance. However, molecular mechanisms of early cell reactions to phytohormone application are currently undisclosed. The present study investigates the participation of phospholipase D and NADPH-oxidase in salicylic acid signal transduction cascade. The activation of lipid signaling enzymes within 15 min of salicylic acid application was shown in Arabidopsis thaliana plants by measuring the phosphatidic acid accumulation. Adding of primary alcohol (1-butanol) to the incubation medium led to phosphatidylbutanol accumulation as a result of phospholipase D (PLD) action in wild-type and NADPH-oxidase RbohD deficient plants. Salicylic acid induced rapid increase in NADPH-oxidase activity in histochemical assay with nitroblue tetrazolium but the reaction was not observed in presence of 1-butanol and NADPH-oxidase inhibitor diphenylene iodide (DPI). The further physiological effect of salicylic acid and inhibitory analysis of the signaling cascade were made in the guard cell model. Stomatal closure induced by salicylic acid was inhibited by 1-butanol and DPI treatment. rbohD transgenic plants showed impaired stomatal reaction upon phytohormone effect, while the reaction to H2O2 did not differ from that of wild-type plants. Thus a key role of NADPH-oxidase D-isoform in the process of stomatal closure in response to salicylic acid has been postulated. It has enabled to predict a cascade implication of PLD and NADPH oxidase to salicylic acid signaling pathway.

  10. Blockade of TGF-β 1 Signalling Inhibits Cardiac NADPH Oxidase Overactivity in Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    José Luis Miguel-Carrasco

    2012-01-01

    Full Text Available NADPH oxidases constitute a major source of superoxide anion (⋅O2 - in hypertension. Several studies suggest an important role of NADPH oxidases in different effects mediated by TGF-β 1. In this study we show that chronic administration of P144, a peptide synthesized from type III TGF-β 1 receptor, significantly reduced the cardiac NADPH oxidase expression and activity as well as in the nitrotyrosine levels observed in control spontaneously hypertensive rats (V-SHR to levels similar to control normotensive Wistar Kyoto rats. In addition, P144 was also able to reduce the significant increases in the expression of collagen type I protein and mRNA observed in hearts from V-SHR. In addition, positive correlations between collagen expression, NADPH oxidase activity, and nitrotyrosine levels were found in all animals. Finally, TGF-β 1-stimulated Rat-2 exhibited significant increases in NADPH oxidase activity that was inhibited in the presence of P144. It could be concluded that the blockade of TGF-β 1 with P144 inhibited cardiac NADPH oxidase in SHR, thus adding new data to elucidate the involvement of this enzyme in the profibrotic actions of TGF-β 1.

  11. Molecular evolution of the polyamine oxidase gene family in Metazoa

    Directory of Open Access Journals (Sweden)

    Polticelli Fabio

    2012-06-01

    Full Text Available Abstract Background Polyamine oxidase enzymes catalyze the oxidation of polyamines and acetylpolyamines. Since polyamines are basic regulators of cell growth and proliferation, their homeostasis is crucial for cell life. Members of the polyamine oxidase gene family have been identified in a wide variety of animals, including vertebrates, arthropodes, nematodes, placozoa, as well as in plants and fungi. Polyamine oxidases (PAOs from yeast can oxidize spermine, N1-acetylspermine, and N1-acetylspermidine, however, in vertebrates two different enzymes, namely spermine oxidase (SMO and acetylpolyamine oxidase (APAO, specifically catalyze the oxidation of spermine, and N1-acetylspermine/N1-acetylspermidine, respectively. Little is known about the molecular evolutionary history of these enzymes. However, since the yeast PAO is able to catalyze the oxidation of both acetylated and non acetylated polyamines, and in vertebrates these functions are addressed by two specialized polyamine oxidase subfamilies (APAO and SMO, it can be hypothesized an ancestral reference for the former enzyme from which the latter would have been derived. Results We analysed 36 SMO, 26 APAO, and 14 PAO homologue protein sequences from 54 taxa including various vertebrates and invertebrates. The analysis of the full-length sequences and the principal domains of vertebrate and invertebrate PAOs yielded consensus primary protein sequences for vertebrate SMOs and APAOs, and invertebrate PAOs. This analysis, coupled to molecular modeling techniques, also unveiled sequence regions that confer specific structural and functional properties, including substrate specificity, by the different PAO subfamilies. Molecular phylogenetic trees revealed a basal position of all the invertebrates PAO enzymes relative to vertebrate SMOs and APAOs. PAOs from insects constitute a monophyletic clade. Two PAO variants sampled in the amphioxus are basal to the dichotomy between two well supported

  12. Study of Drug Metabolism by Xanthine Oxidase

    Directory of Open Access Journals (Sweden)

    Lizhou Sun

    2012-04-01

    Full Text Available In this work, we report the studies of drug metabolism by xanthine oxidase (XOD with electrochemical techniques. Firstly, a pair of stable, well-defined and quasi-reversible oxidation/reduction peaks is obtained with the formal potential at −413.1 mV (vs. SCE after embedding XOD in salmon sperm DNA membrane on the surface of pyrolytic graphite electrode. Then, a new steady peak can be observed at −730 mV (vs. SCE upon the addition of 6-mercaptopurine (6-MP to the electrochemical system, indicating the metabolism of 6-MP by XOD. Furthermore, the chronoamperometric response shows that the current of the catalytic peak located at −730 mV increases with addition of 6-MP in a concentration-dependent manner, and the increase of the chronoamperometric current can be inhibited by an XOD inhibitor, quercetin. Therefore, our results prove that XOD/DNA modified electrode can be efficiently used to study the metabolism of 6-MP, which may provide a convenient approach for in vitro studies on enzyme-catalyzed drug metabolism.

  13. Cholesterol: A modulator of the phagocyte NADPH oxidase activity - A cell-free study

    Directory of Open Access Journals (Sweden)

    Rawand Masoud

    2014-01-01

    Full Text Available The NADPH oxidase Nox2, a multi-subunit enzyme complex comprising membrane and cytosolic proteins, catalyzes a very intense production of superoxide ions O2•−, which are transformed into other reactive oxygen species (ROS. In vitro, it has to be activated by addition of amphiphiles like arachidonic acid (AA. It has been shown that the membrane part of phagocyte NADPH oxidase is present in lipid rafts rich in cholesterol. Cholesterol plays a significant role in the development of cardio-vascular diseases that are always accompanied by oxidative stress. Our aim was to investigate the influence of cholesterol on the activation process of NADPH oxidase. Our results clearly show that, in a cell-free system, cholesterol is not an efficient activator of NADPH oxidase like arachidonic acid (AA, however it triggers a basal low superoxide production at concentrations similar to what found in neutrophile. A higher concentration, if present during the assembly process of the enzyme, has an inhibitory role on the production of O2•−. Added cholesterol acts on both cytosolic and membrane components, leading to imperfect assembly and decreasing the affinity of cytosolic subunits to the membrane ones. Added to the cytosolic proteins, it retains their conformations but still allows some conformational change induced by AA addition, indispensable to activation of NADPH oxidase.

  14. Dimer interface of bovine cytochrome c oxidase is influenced by local posttranslational modifications and lipid binding.

    Science.gov (United States)

    Liko, Idlir; Degiacomi, Matteo T; Mohammed, Shabaz; Yoshikawa, Shinya; Schmidt, Carla; Robinson, Carol V

    2016-07-19

    Bovine cytochrome c oxidase is an integral membrane protein complex comprising 13 protein subunits and associated lipids. Dimerization of the complex has been proposed; however, definitive evidence for the dimer is lacking. We used advanced mass spectrometry methods to investigate the oligomeric state of cytochrome c oxidase and the potential role of lipids and posttranslational modifications in its subunit interfaces. Mass spectrometry of the intact protein complex revealed that both the monomer and the dimer are stabilized by large lipid entities. We identified these lipid species from the purified protein complex, thus implying that they interact specifically with the enzyme. We further identified phosphorylation and acetylation sites of cytochrome c oxidase, located in the peripheral subunits and in the dimer interface, respectively. Comparing our phosphorylation and acetylation sites with those found in previous studies of bovine, mouse, rat, and human cytochrome c oxidase, we found that whereas some acetylation sites within the dimer interface are conserved, suggesting a role for regulation and stabilization of the dimer, phosphorylation sites were less conserved and more transient. Our results therefore provide insights into the locations and interactions of lipids with acetylated residues within the dimer interface of this enzyme, and thereby contribute to a better understanding of its structure in the natural membrane. Moreover dimeric cytochrome c oxidase, comprising 20 transmembrane, six extramembrane subunits, and associated lipids, represents the largest integral membrane protein complex that has been transferred via electrospray intact into the gas phase of a mass spectrometer, representing a significant technological advance.

  15. Forage Polyphenol Oxidase and Ruminant Livestock Nutrition

    Directory of Open Access Journals (Sweden)

    Michael Richard F. Lee

    2014-12-01

    Full Text Available Polyphenol oxidase (PPO is associated with the detrimental effect of browning fruit and vegetables, however interest within PPO containing forage crops has grown since the brownng reaction was associated with reduced nitrogen (N losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage increased the quality of protein, improving N-use efficiency (NUE when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalysing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP. If the protein is an enzyme the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase un-degraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated with entrapment within PBP reducing access to microbial lipases or differences in rumen digestion kinetics of red clover.

  16. Intracellular lysyl oxidase: Effect of a specific inhibitor on nuclear mass in proliferating cells

    Energy Technology Data Exchange (ETDEWEB)

    Saad, Fawzy A. [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Torres, Marie [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Wang, Hao [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States); Graham, Lila, E-mail: lilagraham@cs.com [Laboratory for the Study of Skeletal Disorders and Rehabilitation, Department of Orthopedics, Children' s Hospital Boston, 300 Longwood Avenue EN926, Boston, MA 02115 (United States); Harvard Medical School, Boston, MA 02115 (United States)

    2010-06-11

    LOX, the principal enzyme involved in crosslinking of collagen, was the first of several lysyl oxidase isotypes to be characterized. Its active form was believed to be exclusively extracellular. Active LOX was later reported to be present in cell nuclei; its function there is unknown. LOX expression opposes the effect of mutationally activated Ras, which is present in about 30% of human cancers. The mechanism of LOX in countering the action of Ras is also unknown. In the present work, assessment of nuclear protein for possible effects of lysyl oxidase activity led to the discovery that proliferating cells dramatically increase their nuclear protein content when exposed to BAPN ({beta}-aminopropionitrile), a highly specific lysyl oxidase inhibitor that reportedly blocks LOX inhibition of Ras-induced oocyte maturation. In three cell types (PC12 cells, A7r5 smooth muscle cells, and NIH 3T3 fibroblasts), BAPN caused a 1.8-, 1.7-, and 2.1-fold increase in total nuclear protein per cell, respectively, affecting all major components in both nuclear matrix and chromatin fractions. Since nuclear size is correlated with proliferative status, enzyme activity restricting nuclear growth may be involved in the lysyl oxidase tumor suppressive effect. Evidence is also presented for the presence of apparent lysyl oxidase isotype(s) containing a highly conserved LOX active site sequence in the nuclei of PC12 cells, which do not manufacture extracellular lysyl oxidase substrates. Results reported here support the hypothesis that nuclear lysyl oxidase regulates nuclear growth, and thereby modulates cell proliferation.

  17. Expression of a copper-containing amine oxidase by human ciliary body.

    Science.gov (United States)

    Howell, D N; Valnickova, Z; Oury, T D; Miller, S E; Sanfilippo, F P; Enghild, J J

    1998-09-08

    To examine the molecular structure and ultrastructural distribution of a novel amine oxidase in human ciliary body. Human ciliary bodies were solubilized with a nonionic detergent. The solubilized material was subjected to affinity chromatography with 2B4.14.1, a monoclonal antibody which recognizes a family of ciliary body glycoproteins. Proteins eluted from the affinity column were further separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Peptides produced from a 2B4.14. 1-reactive protein with an approximate molecular weight of 100 kDa were analyzed by Edman degradation. The protein thus identified was further examined by Western blotting and immunoelectron microscopy with anti-peptide antisera. Peptide sequences from the 100 kDa ciliary body protein were identical to the predicted protein sequence of an amine oxidase identified recently in a human placental cDNA library. The identity of the ciliary body protein was confirmed by Western blotting with rabbit antiserum generated against the predicted carboxy-terminal peptide of human placenta amine oxidase. Western blotting under nonreducing conditions and following glycosidase digestion indicated that the native enzyme is a disulfide-linked homodimer with multiple N-linked oligosaccharide side chains. By immunoelectron microscopy, the ciliary body amine oxidase was localized to the plasma membranes of inner epithelial cells. Human placenta amine oxidase is present on the plasma membranes of ciliary body inner epithelial cells. This finding provides a potential explanation for amine oxidase enzyme activity detected in previous studies of anterior segment tissues. Though the functional role of human placenta amine oxidase in the eye is unclear, it may contribute to the production of H2O2 in aqueous humor.

  18. PHARMACOLOGICAL EFFECTS OF SNAKE VENOM L- AMINO ACID OXIDASES

    Directory of Open Access Journals (Sweden)

    Joseph Baby

    2011-02-01

    Full Text Available L-Amino acid oxidases are flavoenzymes which catalyze the stereospecific oxidative deamination of an L-amino acid substrate to a corresponding a-ketoacid with hydrogen peroxide and ammonia production. These enzymes, which are widely distributed in many different organisms, exhibit a marked affinity for hydrophobic amino acids, including phenylalanine, tryptophan, tyrosine, and leucine. Snake venom LAAO induces platelet aggregation and cytotoxicity in various cancer cell lines. The enzyme has antibacterial activity inhibiting the growth of Gram-positive (Bacillus subtilis and Gram-negative (Escherichia coli bacteria. Specific substrates for the isolated protein are L-phenylalanine, L-tryptophan, L-methionine and L-leucine. The enzyme is stable at low temperatures (−20 ºC, −70 ºC and loses its activity by heating at 70 ºC. These enzymes are postulated to be toxins that may be involved in the allergic inflammatory response and specifically associated with mammalian endothelial cells damage. However, in the last decade these enzymes have become an interesting subject for pharmacological, structural and molecular characterizations. Structural and functional investigations of these enzymes can contribute to the advancement of toxinology and to the elaboration of novel therapeutic agents.

  19. Polyphenol Oxidase as a Biochemical Seed Defense Mechanism

    Directory of Open Access Journals (Sweden)

    E. Patrick Fuerst

    2014-12-01

    Full Text Available Seed dormancy and resistance to decay are fundamental survival strategies, which allow a population of seeds to germinate over long periods of time. Seeds have physical, chemical, and biological defense mechanisms that protect their food reserves from decay-inducing organisms and herbivores. Here, we hypothesize that seeds also possess enzyme-based biochemical defenses, based on induction of the plant defense enzyme, polyphenol oxidase (PPO, when wild oat (Avena fatua L. caryopses and seeds were challenged with seed-decaying Fusarium fungi. These studies suggest that dormant seeds are capable of mounting a defense response to pathogens. The pathogen-induced PPO activity from wild oat was attributed to a soluble isoform of the enzyme that appeared to result, at least in part, from proteolytic activation of a latent PPO isoform. PPO activity was also induced in wild oat hulls (lemma and palea, non-living tissues that cover and protect the caryopsis. These results are consistent with the hypothesis that seeds possess inducible enzyme-based biochemical defenses arrayed on the exterior of seeds and these defenses represent a fundamental mechanism of seed survival and longevity in the soil. Enzyme-based biochemical defenses may have broader implications since they may apply to other defense enzymes as well as to a diversity of plant species and ecosystems.

  20. The effects of non-medically used psychoactive drugs on monoamine neurotransmission in rat brain.

    Science.gov (United States)

    Nagai, Fumiko; Nonaka, Ryouichi; Satoh Hisashi Kamimura, Kanako

    2007-03-22

    We developed a reproducible, simple, and small-scale method for determining the re-uptake and release of monoamines (dopamine, serotonin (5-HT) and norepinephrine) using rat brain synaptosomes. These assays were then applied to study the effects of different kinds of non-medically used psychoactive drugs on monoamine re-uptake and release. The phenethylamine derivatives, 4-fluoroamphetamine, 2-methylamino-3,4-methylene-dioxy-propiophenone (methylone), 1-(1,3-benzodioxol-5-yl)-2-butanamine (BDB), and N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine (MBDB), had strong inhibitory effects on the re-uptake of dopamine, 5-HT and norepinephrine. 4-Fluoroamphetamine, methylone and BDB also strongly increased the release of the three monoamines, but MBDB increased 5-HT and norepinephrine release, but had little effect on dopamine release. However, 2,5-dimethoxy-4-iodophenethylamine (2C-I), 2,5-dimethoxy-4-ethylphenethylamine (2C-E), 2,5-dimethoxy-4-chlorophenethylamine (2C-C), 2,4,5-trimethoxyamphetamine (TMA-2) and 2,4,6-trimethoxyamphetamine (TMA-6), which are methoxylated phenethylamine derivatives, slightly influenced the re-uptake and release of monoamines. Alpha-metyltryptamine (AMT), a tryptamine derivative, was one of the strongest re-uptake inhibitors and releasers of the three monoamines. The tryptamine derivative, 5-methoxy-alpha-methyltryptamine (5-MeO-AMT), also strongly inhibited re-uptake and increased the release of the three monoamines. N,N-dipropyltryptamine (DPT), 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), 5-methoxy-N,N-methylisopropyltryptamine (5-MeO-MIPT), and 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) inhibited monoamine re-uptake, but had a few effects on monoamine release. 1-(3-Chlorophenyl)piperazine (3CPP) and 1-(methoxyphenyl)piperazine (4MPP), which are piperazine derivatives, inhibited monoamine re-uptake and accelerated their release. The results suggest that some designer drugs strongly act on the central nerve system to the same

  1. 漆黄素联合胡椒碱的抗抑郁作用及其机制研究%Antidepressant like effect of acute administration with fisetin combined with piperine and its monoamine mechanism

    Institute of Scientific and Technical Information of China (English)

    王钱东; 吴淑娟; 朱国文; 潘建春

    2014-01-01

    目的:探讨低剂量漆黄素(Fisetin)联合阈下剂量胡椒碱的抗抑郁作用是否涉及单胺机制。方法采用行为绝望抑郁模型,即小鼠强迫游泳实验和悬尾实验,观察低剂量漆黄素与阈下剂量胡椒碱急性给药对小鼠绝望模型不动时间的影响,同时观察两药联用对小鼠自主活动的影响。高效液相-电化学检测脑区中单胺递质的含量,荧光分光光度法检测单胺氧化酶(MAO)活性。结果漆黄素(1.25 mg/kg,2.5 mg/kg,5 mg/kg, ig)与阈下剂量胡椒碱2.5 mg/kg·ip联合应用能显著减少小鼠强迫游泳和悬尾实验中的不动时间,且实验剂量范围内药物不影响小鼠的自主活动。低剂量漆黄素与阈下剂量胡椒碱合用能升高海马、皮层和杏仁核中的单胺递质水平同时降低脑内的MAO活性,并且具有统计学意义。结论低剂量漆黄素与阈下剂量胡椒碱联合用药能改善抑郁症样行为,该机制可能是通过抑制单胺氧化酶的活性,从而增加相关的神经递质。%Objective To explore the antidepressant effects of low dose fisetin combined with piperine and its possible mechanism. Methods The tail suspension test and the forced swimming test were used to explore the antidepressant ef-fects of low dose fisetin combined with piperine. In addition, the locomotor activity test was used to exclude the false positive effect in behavioral despair tests. High performance liquid chromatography (HPLC) was used to determine the expression of monoamine. The monoamine oxidase activity in the mouse brain was also determined by fluorospec-trophotometry. Results The results showed that fisetin (1.25 mg/kg, 2.5 mg/kg and 5 mg/kg, ig) combined with piperine (2.5 mg/kg, ip) significantly reduced the duration of immobility in both tail suspension and forced swimming tests. The effective doses did not alter locomotor activity. Moreover, neurochemical assays showed that its produced an increase in monoamine levels in the

  2. Multiple controls affect arsenite oxidase gene expression in Herminiimonas arsenicoxydans

    Directory of Open Access Journals (Sweden)

    Coppée Jean-Yves

    2010-02-01

    Full Text Available Abstract Background Both the speciation and toxicity of arsenic are affected by bacterial transformations, i.e. oxidation, reduction or methylation. These transformations have a major impact on environmental contamination and more particularly on arsenic contamination of drinking water. Herminiimonas arsenicoxydans has been isolated from an arsenic- contaminated environment and has developed various mechanisms for coping with arsenic, including the oxidation of As(III to As(V as a detoxification mechanism. Results In the present study, a differential transcriptome analysis was used to identify genes, including arsenite oxidase encoding genes, involved in the response of H. arsenicoxydans to As(III. To get insight into the molecular mechanisms of this enzyme activity, a Tn5 transposon mutagenesis was performed. Transposon insertions resulting in a lack of arsenite oxidase activity disrupted aoxR and aoxS genes, showing that the aox operon transcription is regulated by the AoxRS two-component system. Remarkably, transposon insertions were also identified in rpoN coding for the alternative N sigma factor (σ54 of RNA polymerase and in dnaJ coding for the Hsp70 co-chaperone. Western blotting with anti-AoxB antibodies and quantitative RT-PCR experiments allowed us to demonstrate that the rpoN and dnaJ gene products are involved in the control of arsenite oxidase gene expression. Finally, the transcriptional start site of the aoxAB operon was determined using rapid amplification of cDNA ends (RACE and a putative -12/-24 σ54-dependent promoter motif was identified upstream of aoxAB coding sequences. Conclusion These results reveal the existence of novel molecular regulatory processes governing arsenite oxidase expression in H. arsenicoxydans. These data are summarized in a model that functionally integrates arsenite oxidation in the adaptive response to As(III in this microorganism.

  3. Sensing based on the motion of enzyme-modified nanorods

    DEFF Research Database (Denmark)

    Bunea, Ada-Ioana; Pavel, Ileana-Alexandra; David, Sorin;

    2015-01-01

    Asymmetric modification with an enzyme confers nanorods an enhanced diffusive motion that is dependent on the concentration of the enzyme substrate. In turn, such a motion opens the possibility of determining the concentration of the enzyme substrate by measuring the diffusion coefficient...... of nanorods modified with the appropriate enzyme. Nanorods, with a Pt and a polypyrrole (PPy) segment, were fabricated. The PPy segment of such nanorods was then modified with glucose oxidase (GOx), glutamate oxidase (GluOx), or xanthine oxidase (XOD). Calibration curves, linking the diffusion coefficient...... media. Based on the obtained results we are confident that our motion-based approach to sensing can be developed to the point where different nanorods in a mixture simultaneously report on the concentration of different compounds with good temporal and spatial resolution....

  4. Mesocorticolimbic monoamine correlates of methamphetamine sensitization and motivation

    Directory of Open Access Journals (Sweden)

    Kevin D Lominac

    2014-05-01

    Full Text Available Methamphetamine (MA is a highly addictive psychomotor stimulant, with life-time prevalence rates of abuse ranging from 5-10% world-wide. Yet, a paucity of research exists regarding MA addiction vulnerability/resiliency and neurobiological mediators of the transition to addiction that might occur upon repeated low-dose MA exposure, more characteristic of early drug use. As stimulant-elicited neuroplasticity within dopamine neurons innervating the nucleus accumbens (NAC and prefrontal cortex (PFC is theorized as central for addiction-related behavioral anomalies, we used a multi-disciplinary research approach in mice to examine the interactions between sub-toxic MA dosing, motivation for MA and mesocorticolimbic monoamines. Biochemical studies of C57BL/6J (B6 mice revealed short- (1 day, as well as longer-term (21 days, changes in extracellular dopamine, DAT and/or D2 receptors during withdrawal from 10, once daily, 2 mg/kg MA injections. Follow-up biochemical studies conducted in mice selectively bred for high versus low MA drinking (respectively, MAHDR vs. MALDR mice, provided novel support for anomalies in mesocorticolimbic dopamine as a correlate of genetic vulnerability to high MA intake. Finally, neuropharmacological targeting of NAC dopamine in MA-treated B6 mice demonstrated a bi-directional regulation of MA-induced place-conditioning. These results extend extant literature for MA neurotoxicity by demonstrating that even subchronic exposure to relatively low MA doses are sufficient to elicit relatively long-lasting changes in mesocorticolimbic dopamine and that drug-induced or idiopathic anomalies in mesocorticolimbic dopamine may underpin vulnerability/resiliency to MA addiction.

  5. H2O2-Forming NADH Oxidase with Diaphorase (Cytochrome) Activity from Archaeoglobus fulgidus

    OpenAIRE

    Reed, David W.; Millstein, Jack; Hartzell, Patricia L.

    2001-01-01

    An enzyme exhibiting NADH oxidase (diaphorase) activity was isolated from the hyperthermophilic sulfate-reducing anaerobe Archaeoglobus fulgidus. N-terminal sequence of the protein indicates that it is coded for by open reading frame AF0395 in the A. fulgidus genome. The gene AF0395 was cloned and its product was purified from Escherichia coli. Like the native NADH oxidase (NoxA2), the recombinant NoxA2 (rNoxA2) has an apparent molecular mass of 47 kDa, requires flavin adenine dinucleotide fo...

  6. Childhood encephalomyopathy with cytochrome c oxidase deficiency, ataxia, muscle wasting, and mental impairment.

    Science.gov (United States)

    Angelini, C; Bresolin, N; Pegolo, G; Bet, L; Rinaldo, P; Trevisan, C; Vergani, L

    1986-08-01

    The son of third cousins was normal until age 2 when he had difficulty walking. At age 8 there was limb weakness, ataxia, loss of tendon reflexes, dislalia, and he was mildly retarded. During fasting, urinary organic acid excretion was abnormally high. Cytochrome c oxidase activity in muscle was 7% of the normal mean. The enzyme in platelets was 16% of controls with a decreased cytochrome aa3 peak. These data suggest an autosomal recessive transmission of this variant of cytochrome c oxidase deficiency.

  7. Chronic Effect of Aspartame on Ionic Homeostasis and Monoamine Neurotransmitters in the Rat Brain.

    Science.gov (United States)

    Abhilash, M; Alex, Manju; Mathews, Varghese V; Nair, R Harikumaran

    2014-05-28

    Aspartame is one of the most widely used artificial sweeteners globally. Data concerning acute neurotoxicity of aspartame is controversial, and knowledge on its chronic effect is limited. In the current study, we investigated the chronic effects of aspartame on ionic homeostasis and regional monoamine neurotransmitter concentrations in the brain. Our results showed that aspartame at high dose caused a disturbance in ionic homeostasis and induced apoptosis in the brain. We also investigated the effects of aspartame on brain regional monoamine synthesis, and the results revealed that there was a significant decrease of dopamine in corpus striatum and cerebral cortex and of serotonin in corpus striatum. Moreover, aspartame treatment significantly alters the tyrosine hydroxylase activity and amino acids levels in the brain. Our data suggest that chronic use of aspartame may affect electrolyte homeostasis and monoamine neurotransmitter synthesis dose dependently, and this might have a possible effect on cognitive functions.

  8. Brain monoamine metabolism is altered in rats following spontaneous, long-distance running.

    Science.gov (United States)

    Elam, M; Svensson, T H; Thorén, P

    1987-06-01

    Brain monoamine metabolism in rats was studied during spontaneous, long-term running in a microprocessor-controlled wheel cage. Immediately after heavy spontaneous exercise, DOPA accumulation was decreased in dopamine-rich brain regions such as the limbic forebrain and corpus striatum, indicating a decreased rate of synthesis of dopamine in brain. In contrast, DOPA accumulation was increased in the noradrenaline-predominated region of the brain stem, indicating an increased synthesis of noradrenaline in this region. Alterations in brain monoamine metabolism were normalized in exercising animals analysed 24 h after the last running period. Changes in brain monoamine metabolism may be involved in the mechanisms underlying the clinically observed psychological effects of physical exercise.

  9. A kinome wide screen identifies novel kinases involved in regulation of monoamine transporter function

    DEFF Research Database (Denmark)

    Vuorenpää, Anne Elina; Ammendrup-Johnsen, Ina; Jorgensen, Trine N.

    2016-01-01

    cells (CAD) and rat chromocytoma (PC12) cells. Whereas SIK3 likely transcriptionally regulated expression of the three transfected transporters, depletion of PKA C-α was shown to decrease SERT function. Depletion of PrKX caused decreased surface expression and function of DAT without changing protein...... levels, suggesting that PrKX stabilizes the transporter at the cell surface. Summarized, our data provide novel insight into kinome regulation of the monoamine transporters and identifies PrKX as a yet unappreciated possible regulator of monoamine transporter function....... in regulation of monoamine transporter function and surface expression. A primary screen in HEK 293 cells stably expressing DAT or SERT with siRNAs against 573 human kinases revealed 93 kinases putatively regulating transporter function. All 93 hits, which also included kinases previously implicated...

  10. Inhibitory effects of Ruta graveolens L. extract on guinea pig liver aldehyde oxidase.

    Science.gov (United States)

    Pirouzpanah, Saieed; Saieed, Pirouzpanah; Rashidi, Mohammad Reza; Reza, Rashidi Mohammad; Delazar, Abbas; Abbas, Delazar; Razavieh, Seyyed-Vali; Seyyedvali, Razavieh; Hamidi, Aliasghar; Aliasghar, Hamidi

    2006-01-01

    Ruta graveolens L. is a flavonoid-containing medicinal plant with various biological properties. In the present study, the effects of R. graveolens extract on aldehyde oxidase, a molybdenum hydroxylase, are investigated. Aldehyde oxidase was partially purified from liver homogenates of mature male guinea pigs by heat treatment and ammonium sulphate precipitation. The total extract was obtained by macerating the aerial parts of R. graveolens in MeOH 70% and the effect of this extract on the enzyme activity was assayed using phenanthridine, vanillin and benzaldehyde as substrates. Quercetin and its glycoside form, rutin were isolated, purified and identified from the extract and their inhibitory effects on the enzyme were investigated. R. graveolens extract exhibited a high inhibition on aldehyde oxidase activity (89-96%) at 100 microg/ml which was comparable with 10 microM of menadione, a specific potent inhibitor of aldehyde oxidase. The IC50 values for the inhibitory effect of extract against the oxidation of benzaldehyde, vanillin and phenanthridine were 10.4, 10.1, 43.2 microg/ml, respectively. Both quercetin and rutin at 10 microM caused 70-96% and 27-52% inhibition on the enzyme activity, respectively. Quercetin was more potent inhibitor than rutin, but both flavonols exerted their inhibitory effects mostly in a linear mixed-type.

  11. Affinity chromatography purification of cytochrome c binding enzymes.

    OpenAIRE

    Azzi, A; Bill, K; Broger, C

    1982-01-01

    An efficient affinity chromatography procedure for the isolation of mitochondrial cytochrome c oxidase and reductase is described. Saccharomyces cerevisiae cytochrome c was used as a ligand, bound to a thiol-Sepharose 4B gel through cysteine-107. In this way, the site of interaction of cytochrome c with cytochrome oxidase and reductase remained unmodified and available for binding to a number of partner enzymes. The procedure is adequate for the purification of all those proteins having in co...

  12. Traumatic Brain Injury and NADPH Oxidase: A Deep Relationship

    Directory of Open Access Journals (Sweden)

    Cristina Angeloni

    2015-01-01

    Full Text Available Traumatic brain injury (TBI represents one of the major causes of mortality and disability in the world. TBI is characterized by primary damage resulting from the mechanical forces applied to the head as a direct result of the trauma and by the subsequent secondary injury due to a complex cascade of biochemical events that eventually lead to neuronal cell death. Oxidative stress plays a pivotal role in the genesis of the delayed harmful effects contributing to permanent damage. NADPH oxidases (Nox, ubiquitary membrane multisubunit enzymes whose unique function is the production of reactive oxygen species (ROS, have been shown to be a major source of ROS in the brain and to be involved in several neurological diseases. Emerging evidence demonstrates that Nox is upregulated after TBI, suggesting Nox critical role in the onset and development of this pathology. In this review, we summarize the current evidence about the role of Nox enzymes in the pathophysiology of TBI.

  13. Effects of gaseous hydrogen fluoride on oxidative enzymes of Pelargonium zonale leaves

    Energy Technology Data Exchange (ETDEWEB)

    Poovaiah, B.W.; Wiebe, H.H.

    1971-10-01

    Changes in peroxidase and cytochrome oxidase enzymes were established histochemically in hydrogen fluoride fumigated leaves of Pelargonium zonale. Highest peroxidase and cytochrome oxidase activities were localized near the injured areas of fumigated leaves, and the greatest increase was observed in the phloem region.