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Sample records for peroxidase enzyme activity

  1. Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

    Science.gov (United States)

    DeNichilo, Mark O; Panagopoulos, Vasilios; Rayner, Timothy E; Borowicz, Romana A; Greenwood, John E; Evdokiou, Andreas

    2015-05-01

    Myeloperoxidase and eosinophil peroxidase are heme-containing enzymes often physically associated with fibrotic tissue and cancer in various organs, without any direct involvement in promoting fibroblast recruitment and extracellular matrix (ECM) biosynthesis at these sites. We report herein novel findings that show peroxidase enzymes possess a well-conserved profibrogenic capacity to stimulate the migration of fibroblastic cells and promote their ability to secrete collagenous proteins to generate a functional ECM both in vitro and in vivo. Mechanistic studies conducted using cultured fibroblasts show that these cells are capable of rapidly binding and internalizing both myeloperoxidase and eosinophil peroxidase. Peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl 4-hydroxylase-dependent manner that does not require ascorbic acid. This response was blocked by the irreversible myeloperoxidase inhibitor 4-amino-benzoic acid hydrazide, indicating peroxidase catalytic activity is essential for collagen biosynthesis. These results suggest that peroxidase enzymes, such as myeloperoxidase and eosinophil peroxidase, may play a fundamental role in regulating the recruitment of fibroblast and the biosynthesis of collagen ECM at sites of normal tissue repair and fibrosis, with enormous implications for many disease states where infiltrating inflammatory cells deposit peroxidases. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  2. Protecting peroxidase activity of multilayer enzyme-polyion films using outer catalase layers.

    Science.gov (United States)

    Lu, Haiyun; Rusling, James F; Hu, Naifei

    2007-12-27

    Films constructed layer-by-layer on electrodes with architecture {protein/hyaluronic acid (HA)}n containing myoglobin (Mb) or horseradish peroxidase (HRP) were protected against protein damage by H2O2 by using outer catalase layers. Peroxidase activity for substrate oxidation requires activation by H2O2, but {protein/HA}n films without outer catalase layers are damaged slowly and irreversibly by H2O2. The rate and extent of damage were decreased dramatically by adding outer catalase layers to decompose H2O2. Comparative studies suggest that protection results from catalase decomposing a fraction of the H2O2 as it enters the film, rather than by an in-film diffusion barrier. The outer catalase layers controlled the rate of H2O2 entry into inner regions of the film, and they biased the system to favor electrocatalytic peroxide reduction over enzyme damage. Catalase-protected {protein/HA}n films had an increased linear concentration range for H2O2 detection. This approach offers an effective way to protect biosensors from damage by H2O2.

  3. Enzyme Technology of Peroxidases: Immobilization, Chemical and Genetic Modification

    Science.gov (United States)

    Longoria, Adriana; Tinoco, Raunel; Torres, Eduardo

    An overview of enzyme technology applied to peroxidases is made. Immobilization on organic, inorganic, and hybrid supports; chemical modification of amino acids and heme group; and genetic modification by site-directed and random mutagenesis are included. Different strategies that were carried out to improve peroxidase performance in terms of stability, selectivity, and catalytic activity are analyzed. Immobilization of peroxidases on inorganic and organic materials enhances the tolerance of peroxidases toward the conditions normally found in many industrial processes, such as the presence of an organic solvent and high temperature. In addition, it is shown that immobilization helps to increase the Total Turnover Number at levels high enough to justify the use of a peroxidase-based biocatalyst in a synthesis process. Chemical modification of peroxidases produces modified enzymes with higher thermostability and wider substrate variability. Finally, through mutagenesis approaches, it is possible to produce modified peroxidases capable of oxidizing nonnatural substrates with high catalytic activity and affinity.

  4. Mutual synergy between catalase and peroxidase activities of the bifunctional enzyme KatG is facilitated by electron hole-hopping within the enzyme.

    Science.gov (United States)

    Njuma, Olive J; Davis, Ian; Ndontsa, Elizabeth N; Krewall, Jessica R; Liu, Aimin; Goodwin, Douglas C

    2017-11-10

    KatG is a bifunctional, heme-dependent enzyme in the front-line defense of numerous bacterial and fungal pathogens against H 2 O 2 -induced oxidative damage from host immune responses. Contrary to the expectation that catalase and peroxidase activities should be mutually antagonistic, peroxidatic electron donors (PxEDs) enhance KatG catalase activity. Here, we establish the mechanism of synergistic cooperation between these activities. We show that at low pH values KatG can fully convert H 2 O 2 to O 2 and H 2 O only if a PxED is present in the reaction mixture. Stopped-flow spectroscopy results indicated rapid initial rates of H 2 O 2 disproportionation slowing concomitantly with the accumulation of ferryl-like heme states. These states very slowly returned to resting ( i.e. ferric) enzyme, indicating that they represented catalase-inactive intermediates. We also show that an active-site tryptophan, Trp-321, participates in off-pathway electron transfer. A W321F variant in which the proximal tryptophan was replaced with a non-oxidizable phenylalanine exhibited higher catalase activity and less accumulation of off-pathway heme intermediates. Finally, rapid freeze-quench EPR experiments indicated that both WT and W321F KatG produce the same methionine-tyrosine-tryptophan (MYW) cofactor radical intermediate at the earliest reaction time points and that Trp-321 is the preferred site of off-catalase protein oxidation in the native enzyme. Of note, PxEDs did not affect the formation of the MYW cofactor radical but could reduce non-productive protein-based radical species that accumulate during reaction with H 2 O 2 Our results suggest that catalase-inactive intermediates accumulate because of off-mechanism oxidation, primarily of Trp-321, and PxEDs stimulate KatG catalase activity by preventing the accumulation of inactive intermediates. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Effect of Vitamin C on Glutathione Peroxidase Activities in Pregnant ...

    African Journals Online (AJOL)

    Glutathione peroxidase is one of the most important antioxidant enzymes in humans. We studied the relationship between serum glutathione peroxidase activity and vitamin C ingestion during normal pregnancy in women attending antenatal clinic in the University of Ilorin Teaching Hospital, Ilorin. Glutathione peroxidase ...

  6. Self-Assembled Complexes of Horseradish Peroxidase with Magnetic Nanoparticles Showing Enhanced Peroxidase Activity

    KAUST Repository

    Corgié , Sté phane C.; Kahawong, Patarawan; Duan, Xiaonan; Bowser, Daniel; Edward, Joseph B.; Walker, Larry P.; Giannelis, Emmanuel P.

    2012-01-01

    Bio-nanocatalysts (BNCs) consisting of horseradish peroxidase (HRP) self-assembled with magnetic nanoparticles (MNPs) enhance enzymatic activity due to the faster turnover and lower inhibition of the enzyme. The size and magnetization of the MNPs

  7. Silica Sol-Gel Entrapment of the Enzyme Chloro peroxidase

    International Nuclear Information System (INIS)

    Le, T.; Chan, S.; Ebaid, B.; Sommerhalter, M.

    2015-01-01

    The enzyme chloro peroxidase (CPO) was immobilized in silica sol-gel beads prepared from tetramethoxysilane. The average pore diameter of the silica host structure (∼3 nm) was smaller than the globular CPO diameter (∼6 nm) and the enzyme remained entrapped after sol-gel maturation. The catalytic performance of the entrapped enzyme was assessed via the pyrogallol peroxidation reaction. Sol-gel beads loaded with 4 μg CPO per mL sol solution reached 9-12% relative activity compared to free CPO in solution. Enzyme kinetic analysis revealed a decrease in K_cat but no changes in K_M or K_I . Product release or enzyme damage might thus limit catalytic performance. Yet circular dichroism and visible absorption spectra of transparent CPO sol-gel sheets did not indicate enzyme damage. Activity decline due to methanol exposure was shown to be reversible in solution. To improve catalytic performance the sol-gel protocol was modified. The incorporation of 5, 20, or 40% methyltrimethoxysilane resulted in more brittle sol-gel beads but the catalytic performance increased to 14% relative to free CPO in solution. The use of more acidic casting buffers (ph 4.5 or 5.5 instead of 6.5) resulted in a more porous silica host reaching up to 18% relative activity

  8. Redox regulation of antioxidant enzymes: post-translational modulation of catalase and glutathione peroxidase activity by resveratrol in diabetic rat liver.

    Science.gov (United States)

    Sadi, Gökhan; Bozan, Davut; Yildiz, Huseyin Bekir

    2014-08-01

    Resveratrol is a strong antioxidant that exhibits blood glucose-lowering effects, which might contribute to its usefulness in preventing complications associated with diabetes. The present study aimed to investigate resveratrol effects on catalase (CAT) and glutathione peroxidase (GPx) gene and protein expression, their phosphorylation states and activities in rat liver of STZ-induced diabetes. Diabetes increased the levels of total protein phosphorylation and p-CAT, while mRNA expression, protein levels, and activity were reduced. Although diabetes induced transcriptional repression over GPx, it did not affect the protein levels and activity. When resveratrol was administered to diabetic rats, an increase in activity was associated with an increase in p-GPx levels. Decrease in Sirtuin1 (SIRT1) and nuclear factor erythroid 2-related factor (Nrf2) and increase in nuclear factor kappa B (NFκB) gene expression in diabetes were associated with a decrease in CAT and GPx mRNA expression. A possible compensatory mechanism for reduced gene expression of antioxidant enzymes is proved to be nuclear translocation of redox-sensitive Nrf2 and NFκB in diabetes which is confirmed by the increase in nuclear and decrease in cytoplasmic protein levels of Nrf2 and NFκB. Taken together, these findings revealed that an increase in the oxidized state in diabetes intricately modified the cellular phosphorylation status and regulation of antioxidant enzymes. Gene regulation of antioxidant enzymes was accompanied by nuclear translocation of Nrf2 and NFκB. Resveratrol administration also activated a coordinated cytoprotective response against diabetes-induced changes in liver tissues.

  9. Oxidation of the tryptophan 32 residue of human superoxide dismutase 1 caused by its bicarbonate-dependent peroxidase activity triggers the non-amyloid aggregation of the enzyme.

    Science.gov (United States)

    Coelho, Fernando R; Iqbal, Asif; Linares, Edlaine; Silva, Daniel F; Lima, Filipe S; Cuccovia, Iolanda M; Augusto, Ohara

    2014-10-31

    The role of oxidative post-translational modifications of human superoxide dismutase 1 (hSOD1) in the amyotrophic lateral sclerosis (ALS) pathology is an attractive hypothesis to explore based on several lines of evidence. Among them, the remarkable stability of hSOD1(WT) and several of its ALS-associated mutants suggests that hSOD1 oxidation may precede its conversion to the unfolded and aggregated forms found in ALS patients. The bicarbonate-dependent peroxidase activity of hSOD1 causes oxidation of its own solvent-exposed Trp(32) residue. The resulting products are apparently different from those produced in the absence of bicarbonate and are most likely specific for simian SOD1s, which contain the Trp(32) residue. The aims of this work were to examine whether the bicarbonate-dependent peroxidase activity of hSOD1 (hSOD1(WT) and hSOD1(G93A) mutant) triggers aggregation of the enzyme and to comprehend the role of the Trp(32) residue in the process. The results showed that Trp(32) residues of both enzymes are oxidized to a similar extent to hSOD1-derived tryptophanyl radicals. These radicals decayed to hSOD1-N-formylkynurenine and hSOD1-kynurenine or to a hSOD1 covalent dimer cross-linked by a ditryptophan bond, causing hSOD1 unfolding, oligomerization, and non-amyloid aggregation. The latter process was inhibited by tempol, which recombines with the hSOD1-derived tryptophanyl radical, and did not occur in the absence of bicarbonate or with enzymes that lack the Trp(32) residue (bovine SOD1 and hSOD1(W32F) mutant). The results support a role for the oxidation products of the hSOD1-Trp(32) residue, particularly the covalent dimer, in triggering the non-amyloid aggregation of hSOD1. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Role of thyroid gland on the peroxidase and iodinating enzymes of submaxillary gland

    International Nuclear Information System (INIS)

    Chandra, T.; Das, R.; Datta, A.G.

    1977-01-01

    The peroxidase (EC 1.11.1.7) and iodinase (EC 1.11.1.8) activities of rat submaxillary gland were found to be increased after thyroidectomy. The enzyme activities were maximal on the seventh day after operation and then decreased slightly. However, the enzyme activities were still more than 100% even 28 days following operation. Administration of thyroxine (10 μg/100 g body weight) prevented the increase. Puromycin, cycloheximide, and actinomycin D, the inhibitors of protein synthesis, as well as Thiouracil partially abolished the increase of activities. These results suggest that thyroxine acts as a regulator of the iodinase and peroxidase enzyme(s) of submaxillary gland. Iodine 131 was the isotope used in the experiments. (orig./AJ) [de

  11. Peroxidase activity as a marker for estrogenicity

    International Nuclear Information System (INIS)

    Levy, J.; Liel, Y.; Glick, S.M.

    1981-01-01

    We examined the possibility that peroxidase activity might be a marker for estrogen activity in established estrogen-dependent tissues: dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumours and human breast cancer. In DMBA-induced tumours undergoing regression after ovariectomy or tamoxifen treatment, tumour size decreased by 50%, estradiol receptors (ER) and progesterone receptors (PgR) decreased by 25 and 20%, respectively, but peroxidase activity paradoxically increased six- to sevenfold. In DMBA tumours stimulated by estradiol treatment or by the cessation of tamoxifen administration in intact rats, tumour size increased threefold. ER and PgR increased two- and threefold, respectively, while peroxidase activity decreased 50%. These data indicate an inverse relation between tumour growth, ER and PgR on the one hand, and peroxidase activity on the other. In the human breast cancers there was a singificant negative relation between the presence of ER and peroxidase activity. By using a calibrated Sephadex G-100 column it was shown that uterine peroxidase differs in molecular weight from the peroxidase of rat mammary tumours and that of human breast cancer. (author)

  12. Induction of Laccase, Lignin Peroxidase and Manganese Peroxidase Activities in White-Rot Fungi Using Copper Complexes

    Directory of Open Access Journals (Sweden)

    Martina Vrsanska

    2016-11-01

    Full Text Available Ligninolytic enzymes, such as laccase, lignin peroxidase and manganese peroxidase, are biotechnologically-important enzymes. The ability of five white-rot fungal strains Daedaleopsis confragosa, Fomes fomentarius, Trametes gibbosa, Trametes suaveolens and Trametes versicolor to produce these enzymes has been studied. Three different copper(II complexes have been prepared ((Him[Cu(im4(H2O2](btc·3H2O, where im = imidazole, H3btc = 1,3,5-benzenetricarboxylic acid, [Cu3(pmdien3(btc](ClO43·6H2O and [Cu3(mdpta3(btc](ClO43·4H2O, where pmdien = N,N,N′,N′′,N′′-pentamethyl-diethylenetriamine and mdpta = N,N-bis-(3-aminopropylmethyl- amine, and their potential application for laccase and peroxidases induction have been tested. The enzyme-inducing activities of the complexes were compared with that of copper sulfate, and it has been found that all of the complexes are suitable for the induction of laccase and peroxidase activities in white-rot fungi; however, the newly-synthesized complex M1 showed the greatest potential for the induction. With respect to the different copper inducers, this parameter seems to be important for enzyme activity, which depends also on the fungal strains.

  13. Peroxidase-like activity of magnetoferritin

    Czech Academy of Sciences Publication Activity Database

    Melníková, V.; Pospíšková, K.; Mitróová, Z.; Kopčanský, P.; Šafařík, Ivo

    2014-01-01

    Roč. 181, 3-4 (2014), s. 295-301 ISSN 0026-3672 R&D Projects: GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : magnetoferritin * magnetic nanoparticles * peroxidase-like activity * hydrogen peroxide * oxidative stress Subject RIV: CE - Biochemistry Impact factor: 3.741, year: 2014

  14. Lignin-degrading enzyme activities.

    Science.gov (United States)

    Chen, Yi-ru; Sarkanen, Simo; Wang, Yun-Yan

    2012-01-01

    Over the past three decades, the activities of four kinds of enzyme have been purported to furnish the mechanistic foundations for macromolecular lignin depolymerization in decaying plant cell walls. The pertinent fungal enzymes comprise lignin peroxidase (with a relatively high redox potential), manganese peroxidase, an alkyl aryl etherase, and laccase. The peroxidases and laccase, but not the etherase, are expressed extracellularly by white-rot fungi. A number of these microorganisms exhibit a marked preference toward lignin in their degradation of lignocellulose. Interestingly, some white-rot fungi secrete both kinds of peroxidase but no laccase, while others that are equally effective express extracellular laccase activity but no peroxidases. Actually, none of these enzymes has been reported to possess significant depolymerase activity toward macromolecular lignin substrates that are derived with little chemical modification from the native biopolymer. Here, the assays commonly employed for monitoring the traditional fungal peroxidases, alkyl aryl etherase, and laccase are described in their respective contexts. A soluble native polymeric substrate that can be isolated directly from a conventional milled-wood lignin preparation is characterized in relation to its utility in next-generation lignin-depolymerase assays.

  15. Self-Assembled Complexes of Horseradish Peroxidase with Magnetic Nanoparticles Showing Enhanced Peroxidase Activity

    KAUST Repository

    Corgié, Stéphane C.

    2012-02-15

    Bio-nanocatalysts (BNCs) consisting of horseradish peroxidase (HRP) self-assembled with magnetic nanoparticles (MNPs) enhance enzymatic activity due to the faster turnover and lower inhibition of the enzyme. The size and magnetization of the MNPs affect the formation of the BNCs, and ultimately control the activity of the bound enzymes. Smaller MNPs form small clusters with a low affinity for the HRP. While the turnover for the bound fraction is drastically increased, there is no difference in the H 2O 2 inhibitory concentration. Larger MNPs with a higher magnetization aggregate in larger clusters and have a higher affinity for the enzyme and a lower substrate inhibition. All of the BNCs are more active than the free enzyme or the MNPs (BNCs > HRP ≤laquo; MNPs). Since the BNCs show surprising resilience in various reaction conditions, they may pave the way towards new hybrid biocatalysts with increased activities and unique catalytic properties for magnetosensitive enzymatic reactions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. The Effect of Citrus Aurantium, Foeniculum Vulgare and Rosmarinus Officinalis Essential Oils on Peroxidase Activity

    OpenAIRE

    Maryam Mohajerani (PhD); Afsaneh Aghae i ( MSc )

    2016-01-01

    Background and objective: Peroxidases catalyze protein oxidation and lipid peroxidation. The activity of these enzymes in nerve cells is involved in causing disorders such as Alzheimer's and Parkinson's disease. This study investigated the effect of Citrus aurantium, Foeniculum vulgare and Rosmarinus officinalis essential oils on activity of peroxidase enzyme. Methods: All three medicinal plants were dried at room temperature. Their essential oil was extracted by steam distillation ...

  17. Inhibition of Heme Peroxidase During Phenol Derivatives Oxidation. Possible Molecular Cloaking of the Active Center

    Directory of Open Access Journals (Sweden)

    Juozas Kulys

    2005-10-01

    Full Text Available Abstract: Ab initio quantum chemical calculations have been applied to the study of the molecular structure of phenol derivatives and oligomers produced during peroxidasecatalyzed oxidation. The interaction of substrates and oligomers with Arthromyces ramosus peroxidase was analyzed by docking methods. The most possible interaction site of oligomers is an active center of the peroxidase. The complexation energy increases with increasing oligomer length. However, the complexed oligomers do not form a precise (for the reaction hydrogen bonding network in the active center of the enzyme. It seems likely that strong but non productive docking of the oligomers determines peroxidase inhibition during the reaction.

  18. Apple and quince peroxidase activity in response to essential oils ...

    African Journals Online (AJOL)

    Enzymatic browning arises by peroxidase in fruits. However, essential oils are recognized as natural antioxidant agents. So in this study, the effect of thyme, coriander and rosemary essential oils were evaluated on the reduction of peroxidase activity in apples (Malus domestica Mill. cv Golden delicious), (M. domestica Mill.

  19. Apple and quince peroxidase activity in response to essential oils ...

    African Journals Online (AJOL)

    Jane

    2011-09-28

    Sep 28, 2011 ... activities of edible coatings enriched with natural plant extracts such as rosemary ..... its oxidation by ascorbate peroxidase activity (Talano et al., 2008). ... delicious and quince improved the antioxidant protection of the fruits ...

  20. Glutathione peroxidase activity in the selenium-treated alga Scenedesmus quadricauda

    Czech Academy of Sciences Publication Activity Database

    Vítová, Milada; Bišová, Kateřina; Hlavová, Monika; Zachleder, Vilém; Rucki, M.; Čížková, Mária

    2011-01-01

    Roč. 102, 1-2 (2011), s. 87-94 ISSN 0166-445X R&D Projects: GA ČR GA525/09/0102 Institutional research plan: CEZ:AV0Z50200510 Keywords : Cell cycle * Enzyme activity * Glutathione peroxidase Subject RIV: EE - Microbiology, Virology Impact factor: 3.761, year: 2011

  1. Determining inhibition effects of some aromatic compounds on peroxidase enzyme purified from white and red cabbage

    Energy Technology Data Exchange (ETDEWEB)

    Öztekin, Aykut, E-mail: aoztekin@agri.edu.tr [Ataturk University, Science Faculty, Department of Chemistry, 25240-Erzurum (Turkey); Agri Ibrahim Cecen University Faculty of Arts and Sciences, Department of Chemistry, 04100-Agri (Turkey); Almaz, Züleyha, E-mail: zturkoglu-2344@hotmail.com [Ataturk University, Science Faculty, Department of Chemistry, 25240-Erzurum (Turkey); Mus Alparslan University Faculty of Sciences, Department of Moleculer Biology, 49250-Mus (Turkey); Özdemir, Hasan, E-mail: hozdemir@atauni.edu.tr [Ataturk University, Science Faculty, Department of Chemistry, 25240-Erzurum (Turkey)

    2016-04-18

    Peroxidases (E.C.1.11.1.7) catalyze the one electron oxidation of wide range of substrates. They are used in synthesis reaction, removal of peroxide from industrial wastes, clinical biochemistry and immunoassays. In this study, the white cabbage (Brassica Oleracea var. capitata f. alba) and red cabbage (Brassica oleracea L. var. capitata f. rubra) peroxidase enzymes were purified for investigation of inhibitory effect of some aromatic compounds on these enzymes. IC{sub 50} values and Ki constants were calculated for the molecules of 6-Amino nicotinic hydrazide, 6-Amino-5-bromo nicotinic hydrazide, 2-Amino-5-hydroxy benzohydrazide, 4-Amino-3-hydroxy benzohydrazide on purified enzymes and inhibition type of these molecules were determined. (This research was supported by Ataturk University. Project Number: BAP-2015/98).

  2. Determining inhibition effects of some aromatic compounds on peroxidase enzyme purified from white and red cabbage

    Science.gov (United States)

    Öztekin, Aykut; Almaz, Züleyha; Özdemir, Hasan

    2016-04-01

    Peroxidases (E.C.1.11.1.7) catalyze the one electron oxidation of wide range of substrates. They are used in synthesis reaction, removal of peroxide from industrial wastes, clinical biochemistry and immunoassays. In this study, the white cabbage (Brassica Oleracea var. capitata f. alba) and red cabbage (Brassica oleracea L. var. capitata f. rubra) peroxidase enzymes were purified for investigation of inhibitory effect of some aromatic compounds on these enzymes. IC50 values and Ki constants were calculated for the molecules of 6-Amino nicotinic hydrazide, 6-Amino-5-bromo nicotinic hydrazide, 2-Amino-5-hydroxy benzohydrazide, 4-Amino-3-hydroxy benzohydrazide on purified enzymes and inhibition type of these molecules were determined. (This research was supported by Ataturk University. Project Number: BAP-2015/98).

  3. Determining inhibition effects of some aromatic compounds on peroxidase enzyme purified from white and red cabbage

    International Nuclear Information System (INIS)

    Öztekin, Aykut; Almaz, Züleyha; Özdemir, Hasan

    2016-01-01

    Peroxidases (E.C.1.11.1.7) catalyze the one electron oxidation of wide range of substrates. They are used in synthesis reaction, removal of peroxide from industrial wastes, clinical biochemistry and immunoassays. In this study, the white cabbage (Brassica Oleracea var. capitata f. alba) and red cabbage (Brassica oleracea L. var. capitata f. rubra) peroxidase enzymes were purified for investigation of inhibitory effect of some aromatic compounds on these enzymes. IC_5_0 values and Ki constants were calculated for the molecules of 6-Amino nicotinic hydrazide, 6-Amino-5-bromo nicotinic hydrazide, 2-Amino-5-hydroxy benzohydrazide, 4-Amino-3-hydroxy benzohydrazide on purified enzymes and inhibition type of these molecules were determined. (This research was supported by Ataturk University. Project Number: BAP-2015/98).

  4. Activity of Mn-Oxidizing Peroxidases of Ganoderma lucidum Depending on Cultivation Conditions

    Directory of Open Access Journals (Sweden)

    Jasmina Ćilerdžić

    2015-11-01

    Full Text Available Trunks and stumps of various deciduous species act as natural habitats for Ganoderma lucidum. The chemical composition of their cell wall affects the development of fungal ligninolytic enzyme system as well as its ability to degrade lignin from the plant cell wall. Additionally, numerous compounds structurally similar to lignin can be degraded by the G. lucidum enzyme system which could take important roles in various biotechnological processes. The laccases, which are the dominant enzymes synthesized by G. lucidum, have been studied more extensively than the Mn-oxidizing peroxidases. Therefore, this study aimed to create the dynamics profile of Mn-oxidizing peroxidases activities in four G. lucidum strains, classifying and determining their properties depending on the cultivation type and plant residue as a carbon source in the medium, as well as to establish whether intraspecific variety exists. The findings suggest that submerged cultivation appeared to be a more appropriate cultivation type for enzyme activities compared with solid-state cultivation, and oak sawdust was a better carbon source than wheat straw. Under the optimum conditions, on day 14, G. lucidum BEOFB 431 was characterized by the highest levels of both Mn-dependent and Mn-independent peroxidase activities (4795.5 and 5170.5 U/L, respectively. Strain, cultivation type, and carbon source were factors that affected the profiles of Mn-oxidizing peroxidases isoenzymes.

  5. Peroxidases in nanostructures

    Directory of Open Access Journals (Sweden)

    Ana Maria eCarmona-Ribeiro

    2015-09-01

    Full Text Available Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting and reusability.

  6. Peroxidase activity in Raphanus sativus and its relationship with soil heavy metals

    International Nuclear Information System (INIS)

    Alipour, H.; Zare Myvan, H.; Sharifi, M.

    2009-01-01

    Today heavy metals are important environmental pollutants which generated from human activities and are one of the most important environmental stresses that cause molecular damages to plants through reactive oxygen species formation such as H2O2. Heavy metals are absorbed and accumulated by plants thus are absorbed by human bodies through the food chain. Raphanus sativus is a herbaceous plant within the Brassicaceae family that has different varieties and is used as a food plant in different parts of Iran. Peroxidase is one of the most important enzyme in oxidoreductase super family that can metabolize H2O2. In this research we studied some growth parameters, peroxidase activity and their relationships with heavy metal content and other soil factors in three different populations of radish collected from Sari, Semnan and south of Tehran. After harvesting the plants shoots and roots Peroxidase activity was assayed spectrophotometrically at 470 nm. Our results showed total heavy metal content of shomal 3 station soil and radish plants was higher than other stations, so plants collected from this station had lowest root and shoot lengths, fresh weights, dry weights, protein content and leaf collrophyll content. The peroxidase activity in both leaves and roots of these plants was higher than plants of other stations Therefore our results showed that with increasing heavy metal concentrations in soils peroxidase activity increased.

  7. A Biocatalytic One-Pot Approach for the Preparation of Lignin Oligomers Using an Oxidase/Peroxidase Cascade Enzyme System

    NARCIS (Netherlands)

    Habib, Mohamed H. M.; Deuss, Peter J.; Loncar, Nikola; Trajkovic, Milos; Fraaije, Marco W.

    2017-01-01

    Synthetic lignin was prepared biocatalytically in a one-pot, two-step reaction using an oxidase/peroxidase cascade enzyme system. Using eugenol in combination with eugenol oxidase and a peroxidase, lignin-like material was produced. The cascade reaction takes advantage of the ability of the oxidase

  8. Effect of low concentrations of ozone on the enzymes catalase, peroxidase, papain and urease

    Energy Technology Data Exchange (ETDEWEB)

    Todd, G W

    1958-01-01

    The enzymes catalase, peroxidase, papain and urease were treated in vitro with low concentrations of ozone gas. Wide variations were found in the sensitivity of the enzymes to the inhibitory action of the gas. Papain showed the greatest sensitivity; the rest required a much greater amount of ozone for inactivation. Comparisons of ozone and hydrogen peroxide as inhibitors of papain and urease showed ozone to be 30 times as effective as hydrogen peroxide on papain and 3 times as effective on urease. 14 references, 2 figures, 3 tables.

  9. Spectroscopic and Kinetic Characterization of Peroxidase-Like π-Cation Radical Pinch-Porphyrin-Iron(III Reaction Intermediate Models of Peroxidase Enzymes

    Directory of Open Access Journals (Sweden)

    Samuel Hernández Anzaldo

    2016-06-01

    Full Text Available The spectroscopic and kinetic characterization of two intermediates from the H2O2 oxidation of three dimethyl ester [(proto, (meso, (deuteroporphyrinato (picdien]Fe(III complexes ([FePPPic], [FeMPPic] and [FeDPPic], respectively pinch-porphyrin peroxidase enzyme models, with s = 5/2 and 3/2 Fe(III quantum mixed spin (qms ground states is described herein. The kinetic study by UV/Vis at λmax = 465 nm showed two different types of kinetics during the oxidation process in the guaiacol test for peroxidases (1–3 + guaiacol + H2O2 → oxidation guaiacol products. The first intermediate was observed during the first 24 s of the reaction. When the reaction conditions were changed to higher concentration of pinch-porphyrins and hydrogen peroxide only one type of kinetics was observed. Next, the reaction was performed only between pinch-porphyrins-Fe(III and H2O2, resulting in only two types of kinetics that were developed during the first 0–4 s. After this time a self-oxidation process was observed. Our hypotheses state that the formation of the π-cation radicals, reaction intermediates of the pinch-porphyrin-Fe(III family with the ligand picdien [N,N’-bis-pyridin-2-ylmethyl-propane-1,3-diamine], occurred with unique kinetics that are different from the overall process and was involved in the oxidation pathway. UV-Vis, 1H-NMR and ESR spectra confirmed the formation of such intermediates. The results in this paper highlight the link between different spectroscopic techniques that positively depict the kinetic traits of artificial compounds with enzyme-like activity.

  10. Hepatic and erythrocytic glutathione peroxidase activity in liver diseases.

    Science.gov (United States)

    Cordero, R; Ortiz, A; Hernández, R; López, V; Gómez, M M; Mena, P

    1996-09-01

    Hepatic and erythrocytic glutathione peroxidase activity, together with malondialdehyde levels, were determined as indicators of peroxidation in 83 patients from whom liver biopsies had been taken for diagnostic purposes. On histological study, the patients were classified into groups as minimal changes (including normal liver), steatosis, alcoholic hepatitis, hepatic cirrhosis, light to moderately active chronic hepatitis, and severe chronic active hepatitis. The glutathione peroxidase activity in erythrocytes showed no significant changes in any liver disease group. In the hepatic study, an increased activity was observed in steatosis with respect to the minimal changes group, this increased activity induced by the toxic agent in the initial stages of the alcoholic hepatic disease declining as the hepatic damage progressed. There was a negative correlation between the levels of hepatic malondialdehyde and hepatic glutathione peroxidase in subjects with minimal changes. This suggested the existence of an oxidative equilibrium in this group. This equilibrium is broken in the liver disease groups as was manifest in a positive correlation between malondialdehyde and glutathione peroxidase activity.

  11. Not so monofunctional--a case of thermostable Thermobifida fusca catalase with peroxidase activity.

    Science.gov (United States)

    Lončar, Nikola; Fraaije, Marco W

    2015-03-01

    Thermobifida fusca is a mesothermophilic organism known for its ability to degrade plant biomass and other organics, and it was demonstrated that it represents a rich resource of genes encoding for potent enzymes for biocatalysis. The thermostable catalase from T. fusca has been cloned and overexpressed in Escherichia coli with a yield of 400 mg/L. Heat treatment of disrupted cells at 60 °C for 1 h resulted in enzyme preparation of high purity; hence, no chromatography steps are needed for large-scale production. Except for catalyzing the dismutation of hydrogen peroxide, TfuCat was also found to catalyze oxidations of phenolic compounds. The catalase activity was comparable to other described catalases while peroxidase activity was quite remarkable with a k obs of nearly 1000 s(-1) for catechol. Site directed mutagenesis was used to alter the ratio of peroxidase/catalase activity. Resistance to inhibition by classic catalase inhibitors and an apparent melting temperature of 74 °C classifies this enzyme as a robust biocatalyst. As such, it could compete with other commercially available catalases while the relatively high peroxidase activity also offers new biocatalytic possibilities.

  12. Effect of caffeine on peroxidase activity and gamma-ray-induced oxic and anoxic damage in Hordeum vulgare

    International Nuclear Information System (INIS)

    Balachandran, R.; Kesavan, P.C.

    1978-01-01

    The influence of caffeine during and after gamma radiation of barley seeds was studied using seedling injury and peroxidase activity as parameters. The radiation-induced stimulation of peroxidase activity is evident in eight-day only seedlings but not in embryos (i.e. immediately after irradiation). Caffeine present during irradiation of seeds soaked in oxygenated water diminishes seedling injury and also reduces the peroxidase activity to the level observed in eight-day old seedlings of unirradiated seeds. Caffeine, however, produces just the opposite effect (i.e. enhances the seedling injury and peroxidase activity of eight-day old seedlings) when applied during irradiation of seeds soaked in oxygen-free water. There is no evidence that caffeine effects enzyme activity under in vitro conditions. (author)

  13. Proximity does not contribute to activity enhancement in the glucose oxidase-horseradish peroxidase cascade

    Science.gov (United States)

    Zhang, Yifei; Tsitkov, Stanislav; Hess, Henry

    2016-12-01

    A proximity effect has been invoked to explain the enhanced activity of enzyme cascades on DNA scaffolds. Using the cascade reaction carried out by glucose oxidase and horseradish peroxidase as a model system, here we study the kinetics of the cascade reaction when the enzymes are free in solution, when they are conjugated to each other and when a competing enzyme is present. No proximity effect is found, which is in agreement with models predicting that the rapidly diffusing hydrogen peroxide intermediate is well mixed. We suggest that the reason for the activity enhancement of enzymes localized by DNA scaffolds is that the pH near the surface of the negatively charged DNA nanostructures is lower than that in the bulk solution, creating a more optimal pH environment for the anchored enzymes. Our findings challenge the notion of a proximity effect and provide new insights into the role of DNA scaffolds.

  14. Phenylalanine ammonia-lyase (pal) and peroxidase activity in brown rust infected tissues of pakistani wheat cultivars

    International Nuclear Information System (INIS)

    Riaz, A.; Tahir, M.I.

    2014-01-01

    Besides other factors resistance and susceptibility is the outcome of biochemical processes such as activities of defense-related enzymes. So in this study, Phenylalanine ammonia-lyase (PAL) and Peroxidase activity of resistant (Inqilab-91) and susceptible (Kirin-95) wheat cultivars were determined through spectrophotometer to address the biochemical aspect related to the disease after 8 hours, 24 hours, 48 hours and 72 hours of leaf rust inoculation. The results have shown that these enzymes were present in both the resistant and susceptible cultivars but the activity was more pronounced in the resistant one. The effect of PAL and peroxidase activity was also investigated among inoculated and uninoculated plants within the same cultivar. The activity of both PAL and peroxidase were more significant in inoculated ones. The results have shown that the after 72 hours of inoculation Inqilab-91 had more PAL activity i.e., 5.47 IU/ml/min than in Kirin-95 i.e., 2.08 IU/ml/min at 270 nm. While peroxidase activity in Inqilab-91 was 6.41 IU/ml/min and in Kirin-95, 3.66 IU/ml/min after 72 hours of inoculation, observed under 470 nm wavelength. Increase in one's activity increases the other enzyme's activity. The activity was more prominent after 72 hours of infection as pathogen had successfully established itself in the host plant tissue. The activities of these enzymes act as plants active defense mechanism against the attack of pathogen. (author)

  15. Peroxidase activity in root hairs of cress (lepidium sativum L.) Cytochemical localization and radioactive labelling of wall bound peroxidase

    International Nuclear Information System (INIS)

    Zaar, K.

    1979-01-01

    The ultrastructural localization of peroxidase activity in young, growing root hairs of cress (Lepidium sativum L.) after assay with 3,3'-diaminobenzidine is reported. Prominent peroxidase activity has been found in the dictyosomes and the associated vesicles, in ribosomes on ER-cisternae, as well as in the cell wall. On the basis of both ultrastructural and cytochemical evidence it is proposed that peroxidase in root hairs is synthesized on the ER- and within dictyosome cisternae packaged and transported in secretory vesicles and extruded into the cell wall particularily at the tip region of a root hair. The kinetic of Golgi apparatus mediated peroxidasesecretion was monitored by measuring the 55 Fe protoheme content of primary cell walls. Peroxidase secretion seems to be enhanced during stress incubation in destilled water. Secretory activity in root hairs is 20 times higher than in cells of the root body. (author)

  16. A manganese catalase from Thermomicrobium roseum with peroxidase and catecholase activity.

    Science.gov (United States)

    Baginski, Robin; Sommerhalter, Monika

    2017-01-01

    An enzyme with catechol oxidase activity was identified in Thermomicrobium roseum extracts via solution assays and activity-stained SDS-PAGE. Yet, the genome of T. roseum does not harbor a catecholase gene. The enzyme was purified with two anion exchange chromatography steps and ultimately identified to be a manganese catalase with additional peroxidase and catecholase activity. Catalase activity (6280 ± 430 IU/mg) clearly dominated over pyrogallol peroxidase (231 ± 53 IU/mg) and catecholase (3.07 ± 0.56 IU/mg) activity as determined at 70 °C. Most enzyme kinetic properties were comparable to previously characterized manganese catalase enzymes. Catalase activity was highest at alkaline pH values and showed inhibition by excess substrate and chloride. The apparent K m and k cat values were 20 mM and 2.02 × 10 4  s -1 subunit -1 at 25 °C and pH 7.0.

  17. An Enzyme Switch Employing Direct Electrochemical Communication between Horseradish Peroxidase and a Poly(aniline) Film.

    Science.gov (United States)

    Bartlett, P N; Birkin, P R; Wang, J H; Palmisano, F; De Benedetto, G

    1998-09-01

    An enzyme switch, or microelectrochemical enzyme transistor, responsive to hydrogen peroxide was made by connecting two carbon band electrodes (∼10 μm wide, 4.5 mm long separated by a 20-μm gap) with an anodically grown film of poly(aniline). Horseradish peroxidase (EC 1.11.1.7) was either adsorbed onto the poly(aniline) film or immobilized in an insulating poly(1,2-diaminobenzene) polymer grown electrochemically on top of the poly(aniline) film to complete the device. In the completed device, the conductivity of the poly(aniline) film changes from conducting (between - 0.05 and + 0.3 V vs SCE at pH 5) to insulating (>+0.3 V vs SCE at pH 5) on addition of hydrogen peroxide. The change in conductivity is brought about by oxidation of the poly(aniline) film by direct electrochemical communication between the enzyme and the conducting polymer. This was confirmed by measuring the potential of the poly(aniline) film during switching of the conductivity in the presence of hydrogen peroxide. The devices can be reused by rereducing the poly(aniline) electrochemically to a potential below +0.3 V vs SCE. A blind test showed that the device can be used to determine unknown concentrations of H(2)O(2) in solution and that, when used with hydrogen peroxide concentrations below 0.5 mmol dm(-)(3), the same device maybe reused several times. The possible development of devices of this type for use in applications requiring the measurement of low levels of hydrogen peroxide or horseradish peroxidase is discussed.

  18. Peroxidase activity in Spondias dulcis = Atividade da peroxidase em Spondias dulcis

    Directory of Open Access Journals (Sweden)

    Lúcio Cardozo-Filho

    2010-10-01

    Full Text Available In this study, the best conditions to obtain crude extracts showingPeroxidase activity from Spondia dulcis (caja-mango were evaluated. Fresh fruits (25 g were blended in different sodium phosphate buffer (0.05 to 0.2 M with a pH varying from 3.0 to 9.0. The muddy material was centrifuged for 20 minutes. In order to improve POD activity, the crude extract was submitted to precipitation with ammonium sulfate at 90% saturation. This precipitated was re-suspended in sodium phosphate buffer 0.2 M pH 6.5 and then, optimum pH for activity assay (pH varying from 5.0 to 9.0 and thermal stability (exposure to different temperatures varying from 30 to 75ºC for periods between 0 to 15 minutes were determined. The best conditions for activity assay were in phosphate buffer 0.2 M at pH7.0. The results obtained for thermal inactivation study suggest that the heating at 75ºCfor 15 minutes inactivated 95% of initial POD activity.Foram avaliadas, neste trabalho, algumas condições para a obtenção de extratos brutos com atividade peroxidase de Spondias dulcis (cajá-manga. Frutas frescas (25 g foram trituradas com tampão fosfato de sódio (0,05 a 0,2 M em pHs diferentes (3,0 a 9,0. O material obtido foi centrifugado por 20 min. O extrato bruto foi submetido à precipitação com sulfato de amônio até 90% de saturação. Este precipitado foi ressuspenso em tampão fosfato de sódio 0,2 M pH 6,5 e, assim, o pH ótimo para o ensaio de atividade (pH que varia de 5,0 a 9,0 e a estabilidade térmica (exposição a temperaturas de 30, 60, 65, 70 e 75ºC por um período de 0 a 15 min. deste foram determinados. As melhores condições encontradas para o ensaio de atividade foram em tampão fosfato 0,2 M pH 7,0. Os resultados para a inativação térmica sugerem que o aquecimento a 75ºC por 15 mininativa 95% da atividade de POD inicial.

  19. Peroxidase Activity in Poplar Inoculated with Compatible and Incompetent Isolates of Paxillus involutus

    Directory of Open Access Journals (Sweden)

    ABDUL GAFUR

    2007-06-01

    Full Text Available Peroxidase activity of the hybrid poplar Populus×canescens (Ait. Sm. (= P. tremula L. × P. alba L. inoculated with compatible and incompetent isolates of Paxillus involutus (Batsch Fr. was investigated. Screening of the ectomycorrhizal fungal isolates was initiated with exploration of mycelial growth characteristics and mycorrhizal ability in vitro with poplar. Both traits varied within the fungus although they did not seem to be genetically correlated. While isolates SCO1, NAU, and 031 grew faster than others, only isolates MAJ, SCO1, and 031 were able to form ectomycorrhiza with poplar. Isolates MAJ (compatible and NAU (incompetent were subsequently selected for further experiments. Activity of peroxidase, one of the defense-related enzymes, was examined in pure culture and short root components of compatible and incompetent interactions between poplar and P. involutus. Peroxidase activities increased significantly in poplar inoculated with incompetent isolate of the fungus compared to control, while induction of the same enzyme was not detected in compatible associations.

  20. Effect of phenol on germination capacity and polyphenol oxidase, peroxidase and catalase activities in lettuce

    Directory of Open Access Journals (Sweden)

    Tadić Vojin

    2014-01-01

    Full Text Available In this study we examined the activities of polyphenol oxidase (PPO and antioxidant enzymes, peroxidase (POX and catalase (CAT during lettuce seed germination at different concentrations of phenol. Out of eleven varieties of lettuce, four were chosen according to their germination tolerance to phenol as follows: plants exhibiting high (Ljubljanska ledenka - LJL and Nansen - N and low toleranace (Little Gem - LG and Majska kraljica - MK. A decrease in germination efficiency after exposure to LD50 of phenol was determined for these four varieties. The effects of phenol treatment on POX, CAT and PPO activities were determined after 4, 5, 6, 7 and 8 days of growth at LD50 concentrations. A trend of increased peroxidase activity was observed in seeds grown on LD50 of phenol compared to control seeds. A significant increase in CAT activity was observed at the beginning of treatment for MK, LG and N in seeds grown on phenol as well as in control seeds. A trend of increased PPO activity was observed in all control seeds. We also investigated the affinity of PPO for two different substrates that were used for the determination of enzyme activity. Our results show that LJL and N are the varieties most tolerant to growth on phenol. Here we report on the activities of their antioxidant enzymes and PPO during seed germination. [Projekat Ministarstva nauke Republike Srbije, br. ON173017

  1. The Molecular Mechanism of the Catalase-like Activity in Horseradish Peroxidase.

    Science.gov (United States)

    Campomanes, Pablo; Rothlisberger, Ursula; Alfonso-Prieto, Mercedes; Rovira, Carme

    2015-09-02

    Horseradish peroxidase (HRP) is one of the most relevant peroxidase enzymes, used extensively in immunochemistry and biocatalysis applications. Unlike the closely related catalase enzymes, it exhibits a low activity to disproportionate hydrogen peroxide (H2O2). The origin of this disparity remains unknown due to the lack of atomistic information on the catalase-like reaction in HRP. Using QM(DFT)/MM metadynamics simulations, we uncover the mechanism for reduction of the HRP Compound I intermediate by H2O2 at atomic detail. The reaction begins with a hydrogen atom transfer, forming a peroxyl radical and a Compound II-like species. Reorientation of the peroxyl radical in the active site, concomitant with the transfer of the second hydrogen atom, is the rate-limiting step, with a computed free energy barrier (18.7 kcal/mol, ∼ 6 kcal/mol higher than the one obtained for catalase) in good agreement with experiments. Our simulations reveal the crucial role played by the distal pocket residues in accommodating H2O2, enabling formation of a Compound II-like intermediate, similar to catalases. However, out of the two pathways for Compound II reduction found in catalases, only one is operative in HRP. Moreover, the hydrogen bond network in the distal side of HRP compensates less efficiently than in catalases for the energetic cost required to reorient the peroxyl radical at the rate-determining step. The distal Arg and a water molecule in the "wet" active site of HRP have a substantial impact on the reaction barrier, compared to the "dry" active site in catalase. Therefore, the lower catalase-like efficiency of heme peroxidases compared to catalases can be directly attributed to the different distal pocket architecture, providing hints to engineer peroxidases with a higher rate of H2O2 disproportionation.

  2. Effects of ageing on peroxidase activity and localization in radish (Raphanus sativus L. seeds

    Directory of Open Access Journals (Sweden)

    A. Scialabba

    2010-05-01

    Full Text Available Peroxidase activity was assayed in crude extracts of integument, cotyledons and embryo axis of radish seeds, deteriorated under accelerated ageing conditions. Over five days of ageing, in which germination decreased from 100 to 52%, the enzyme activity in integument was higher than that in other seed parts, increasing in the first days of ageing and then decreasing sharply in extremely aged seeds. Polyacrylamide gel electrophoresis analysis showed four peroxidase isoenzymes with MM of 98, 52.5, 32.8 and 29.5 kDa in the embryo axis of unaged seeds, and only the 32.8 and 29.5 kDa MM isoforms in the integument and cotyledons. In these parts of the seed, only the 29.5 kDa MM isoenzyme increased in activity in early days of ageing and decreased thereafter. In the embryo axis, the 29.5 kDa MM isoenzyme activity increased slowly in the first day of ageing, while the 98 and 52.5 kDa MM isoenzyme activities disappeared. A cytochemical localization of peroxidase activity in the various tissues showed that main differences between unaged and extremely aged seeds occurred in the embryo axis.

  3. Enzymatic removal of phenol and p-chlorophenol in enzyme reactor: Horseradish peroxidase immobilized on magnetic beads

    International Nuclear Information System (INIS)

    Bayramoglu, Guelay; Arica, M. Yakup

    2008-01-01

    Horseradish peroxidase was immobilized on the magnetic poly(glycidylmethacrylate-co-methylmethacrylate) (poly(GMA-MMA)), via covalent bonding and used for the treatment of phenolic wastewater in continuous systems. For this purposes, horseradish peroxidase (HRP) was covalently immobilized onto magnetic poly(GMA-MMA) beds using glutaraldehyde (GA) as a coupling agent. The maximum HRP immobilization capacity of the magnetic poly(GMA-MMA)-GA beads was 3.35 mg g -1 . The immobilized HRP retained 79% of the activity of the free HRP used for immobilization. The immobilized HRP was used for the removal of phenol and p-chlorophenol via polymerization of dissolved phenols in the presence of hydrogen peroxide (H 2 O 2 ). The effect of pH and temperature on the phenol oxidation rate was investigated. The results were compared with the free HRP, which showed that the optimum pH value for the immobilized HRP is similar to that for the free HRP. The optimum pH value for free and immobilized HRP was observed at pH 7.0. The optimum temperature for phenols oxidation with immobilized HRP was between 25 and 35 deg. C and the immobilized HRP has more resistance to temperature inactivation than that of the free form. Finally, the immobilized HRP was operated in a magnetically stabilized fluidized bed reactor, and phenols were successfully removed in the enzyme reactor

  4. Characterization of structure and activity of garlic peroxidase (POX(1B)).

    Science.gov (United States)

    El Ichi, Sarra; Miodek, Anna; Sauriat-Dorizon, Hélène; Mahy, Jean-Pierre; Henry, Céline; Marzouki, Mohamed Nejib; Korri-Youssoufi, Hafsa

    2011-01-01

    Structural characterization and study of the activity of new POX(1B) protein from garlic which has a high peroxidase activity and can be used as a biosensor for the detection of hydrogen peroxide and phenolic compounds were performed and compared with the findings for other heme peroxidases. The structure-function relationship was investigated by analysis of the spectroscopic properties and correlated to the structure determined by a new generation of high-performance hybrid mass spectrometers. The reactivity of the enzyme was analyzed by studies of the redox activity toward various ligands and the reactivity with various substrates. We demonstrated that, in the case of garlic peroxidase, the heme group is pentacoordinated, and has an histidine as a proximal ligand. POX(1B) exhibited a high affinity for hydrogen peroxide as well as various reducing cosubstrates. In addition, high enzyme specificity was demonstrated. The k(cat) and K(M) values were 411 and 400 mM(-1) s(-1) for 3,3',5,5'-tetramethylbenzidine and 2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), respectively. Furthermore, the reduction of nitro compounds in the presence of POX(1B) was demonstrated by iron(II) nitrosoalkane complex assay. In addition, POX(1B) showed a great potential for application for drug metabolism since its ability to react with 1-nitrohexane in the presence of sodium dithionite was demonstrated by the appearance of a characteristic Soret band at 411 nm. The high catalytic efficiency obtained in the case of the new garlic peroxidase (POX(1B)) is suitable for the monitoring of different analytes and biocatalysis.

  5. Effect of γ-radiation on the activities of superoxide dimutase, catalase and peroxidase on the germinating wheat grain (Triticum aestivum,L.)

    International Nuclear Information System (INIS)

    Chakraborti, M.; Chatterjee, G.C.

    1983-01-01

    Effect of γ-radiation on several enzymes like catalase, peroxidase and superoxide dismutase in different parts of germinating wheat seeds has been studied. It was found that superoxide dismutase activity under the influence of γ-radiation was highest in the embryo part and showed maximum activity, 24 hours after germination. The activity exhibited a gradual decline with time. catalase and peroxidase, the stimulatory efect being maximum in the case of catalase activity. The catalase and peroxidase activities were found to be maximally localised in the embryo part and the highest value was attained after 72 hrs. in the case of catalase and after 48 hrs in the case of peroxidase activity. The results indicate that γ-radiation stimulates free radical generation in the embryo along with subsequent increase in the activities of superoside dismutase, catalase and peroxidase. (author)

  6. Ligninolytic enzymes of the fungus Irpex lacteus (Polyporus tulipiferae): isolation and characterization of lignin peroxidase

    Czech Academy of Sciences Publication Activity Database

    Rothschild, N.; Novotný, Čeněk; Šašek, Václav; Dosoretz, C. G.

    2002-01-01

    Roč. 31, - (2002), s. 627-633 ISSN 0141-0229 Institutional research plan: CEZ:AV0Z5020903 Keywords : lignin * peroxidase * heme peroxidase Subject RIV: EE - Microbiology, Virology Impact factor: 1.773, year: 2002

  7. Detection of enzyme activity in decontaminated spices of industrial use

    International Nuclear Information System (INIS)

    Müller, R.; Theobald, R.

    1995-01-01

    A range of decontaminated spices of industrial use have been examinated for their enzymes (catalase, peroxidase, amylase, lipase activity). The genuine enzymes remain fully active in irradiated spices, whereas the microbial load is clearly reduced. In contrast steam treated spices no longer demonstrate enzyme activities. Steam treatment offers e.g. black pepper without lipase activity, which can no longer cause fat deterioration. Low microbial load in combination with clearly detectable enzyme activity in spices is an indication for irradiation, whereas, reduced microbial contamination combined with enzyme inactivation indicate steam treatment of raw material [de

  8. DYNAMICS OF LEAF PEROXIDASE ACTIVITY DURING ONTOGENY OF HEMP PLANTS, IN RELATION TO SEXUAL PHENOTYPE

    Directory of Open Access Journals (Sweden)

    Elena Truta

    2005-08-01

    Full Text Available During vegetation of female and male hemp plants (Cannabis sativa L., five quantitative determinations of peroxidase activities were made (40 days, 55 days, 70 days, 85 days, 105 days. Peroxidase activity presented some differences in hemp plants, between females and males, during their vegetation cycle. In female plants, before anthesis were registered peaks of peroxidase activities. The blossoming of male plants was coincident with the increase of catalitic action of peroxidase. Generally, the male plants displayed greater levels of peroxidasic activity.

  9. Facile synthesis of enzyme-embedded magnetic metal-organic frameworks as a reusable mimic multi-enzyme system: mimetic peroxidase properties and colorimetric sensor.

    Science.gov (United States)

    Hou, Chen; Wang, Yang; Ding, Qinghua; Jiang, Long; Li, Ming; Zhu, Weiwei; Pan, Duo; Zhu, Hao; Liu, Mingzhu

    2015-11-28

    This work reports a facile and easily-achieved approach for enzyme immobilization by embedding glucose oxidase (GOx) in magnetic zeolitic imidazolate framework 8 (mZIF-8) via a de novo approach. As a demonstration of the power of such materials, the resulting GOx embedded mZIF-8 (mZIF-8@GOx) was utilized as a colorimetric sensor for rapid detection of glucose. This method was constructed on the basis of metal-organic frameworks (MOFs), which possessed very fascinating peroxidase-like properties, and the cascade reaction for the visual detection of glucose was combined into one step through the mZIF-8@GOx based mimic multi-enzyme system. After characterization by electron microscopy, X-ray diffraction, nitrogen sorption, fourier transform infrared spectroscopy and vibrating sample magnetometry, the as-prepared mZIF-8@GOx was confirmed with the robust core-shell structure, the monodisperse nanoparticle had an average diameter of about 200 nm and displayed superparamagnetism with a saturation magnetization value of 40.5 emu g(-1), it also exhibited a large surface area of 396.10 m(2) g(-1). As a peroxidase mimic, mZIF-8 was verified to be highly stable and of low cost, and showed a strong affinity towards H2O2. Meanwhile, the mZIF-8 embedded GOx also exhibited improved activity, stability and greatly enhanced selectivity in glucose detection. Moreover, the mZIF-8@GOx had excellent recyclability with high activity (88.7% residual activity after 12 times reuse).

  10. Enzyme with rhamnogalacturonase activity.

    NARCIS (Netherlands)

    Kofod, L.V.; Andersen, L.N.; Dalboge, H.; Kauppinen, M.S.; Christgau, S.; Heldt-Hansen, H.P.; Christophersen, C.; Nielsen, P.M.; Voragen, A.G.J.; Schols, H.A.

    1998-01-01

    An enzyme exhibiting rhamnogalacturonase activity, capable of cleaving a rhamnogalacturonan backbone in such a manner that galacturonic acids are left as the non-reducing ends, and which exhibits activity on hairy regions from a soy bean material and/or on saponified hairy regions from a sugar beet

  11. Measurement of enzyme activity.

    Science.gov (United States)

    Harris, T K; Keshwani, M M

    2009-01-01

    To study and understand the nature of living cells, scientists have continually employed traditional biochemical techniques aimed to fractionate and characterize a designated network of macromolecular components required to carry out a particular cellular function. At the most rudimentary level, cellular functions ultimately entail rapid chemical transformations that otherwise would not occur in the physiological environment of the cell. The term enzyme is used to singularly designate a macromolecular gene product that specifically and greatly enhances the rate of a chemical transformation. Purification and characterization of individual and collective groups of enzymes has been and will remain essential toward advancement of the molecular biological sciences; and developing and utilizing enzyme reaction assays is central to this mission. First, basic kinetic principles are described for understanding chemical reaction rates and the catalytic effects of enzymes on such rates. Then, a number of methods are described for measuring enzyme-catalyzed reaction rates, which mainly differ with regard to techniques used to detect and quantify concentration changes of given reactants or products. Finally, short commentary is given toward formulation of reaction mixtures used to measure enzyme activity. Whereas a comprehensive treatment of enzymatic reaction assays is not within the scope of this chapter, the very core principles that are presented should enable new researchers to better understand the logic and utility of any given enzymatic assay that becomes of interest.

  12. The clinical application of fluorescent-enzyme immunoassay to detect human thyroid peroxidase autoantibody quantitatively

    International Nuclear Information System (INIS)

    Chai Jinyan; Fang Peihua; Li Ning; Zhang Yanli

    2010-01-01

    Objective: To establish a fluorescent-enzyme immunoassay (FEIA) with recombinant human thyroid peroxidase (hTPO) as the antigen. Methods: Sera of 326 healthy people, 119 cases of Hashimoto's thyroiditis (HT), 116 cases of Graves disease (untreated), 28 cases of nodular goiter, 10 ca-ses of subacute thyroiditis and 6 cases of simple goiter were measured by the FEIA with recombinant hTPO as the antigen. Rrank sum test and χ 2 -test were used in inter-groups. Results: (1) Concentration above 4000 U/L was considered to be positive. (2) The intra-assay coefficient of variation (CV) and the inter-as-say CV were 4.59% ∼ 6.52% and 17.37% ∼ 17.45%. (3) The values measured by the FEIA were positively correlated with the values measured by hTPO antibody (hTPOAb) commercial kit (r=0.80, P 2 = 53.45, 39.30, 15.41 and 21.74, all P < 0.01). Conclusions: The method can be applied in the serum measurement of thyroid disease. HT presented the highest positive rate, therefore, the FEIA was an effective method in diagnosing HT. (authors)

  13. The effects of xylitol and sorbitol on lysozyme- and peroxidase-related enzymatic and candidacidal activities.

    Science.gov (United States)

    Kim, Bum-Soo; Chang, Ji-Youn; Kim, Yoon-Young; Kho, Hong-Seop

    2015-07-01

    To investigate whether xylitol and sorbitol affect enzymatic and candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase system. Xylitol and sorbitol were added to hen egg-white lysozyme, bovine lactoperoxidase, glucose oxidase-mediated peroxidase, and whole saliva in solution and on hydroxyapatite surfaces. The enzymatic activities of lysozyme, peroxidase, and glucose oxidase-mediated peroxidase were determined by the turbidimetric method, the NbsSCN assay, and production of oxidized o-dianisidine, respectively. Candidacidal activities were determined by comparing colony forming units using Candida albicans ATCC strains 10231, 11006, and 18804. While xylitol and sorbitol did not affect the enzymatic activity of hen egg-white lysozyme both in solution and on hydroxyapatite surfaces, they did inhibit the enzymatic activity of salivary lysozyme significantly in solution, but not on the surfaces. Xylitol and sorbitol enhanced the enzymatic activities of both bovine lactoperoxidase and salivary peroxidase significantly in a dose-dependent manner in solution, but not on the surfaces. Sorbitol, but not xylitol, inhibited the enzymatic activity of glucose oxidase-mediated peroxidase significantly. Both xylitol and sorbitol did not affect candidacidal activities of hen egg-white lysozyme, the bovine lactoperoxidase system, or the glucose oxidase-mediated bovine lactoperoxidase system. Xylitol and sorbitol inhibited salivary lysozyme activity, but enhanced both bovine lactoperoxidase and salivary peroxidase activities significantly in solution. Xylitol and sorbitol did not augment lysozyme- and peroxidase-related candidacidal activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Magnetic resonance spectral characterization of the heme active site of Coprinus cinereus peroxidase

    International Nuclear Information System (INIS)

    Lukat, G.S.; Rodgers, K.R.; Jabro, M.N.; Goff, H.M.

    1989-01-01

    Examination of the peroxidase isolated from the inkcap Basidiomycete Coprinus cinereus shows that the 42,000-dalton enzyme contains a protoheme IX prosthetic group. Reactivity assays and the electronic absorption spectra of native Coprinus peroxidase and several of its ligand complexes indicate that this enzyme has characteristics similar to those reported for horseradish peroxidase. In this paper, the authors characterize the H 2 O 2 -oxidized forms of Coprinus peroxidase compounds I, II, and III by electronic absorption and magnetic resonance spectroscopies. Electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) studies of this Coprinus peroxidase indicate the presence of high-spin Fe(III) in the native protein and a number of differences between the heme site of Coprinus peroxidase and horseradish peroxidase. Carbon-13 (of the ferrous CO adduct) and nitrogen-15 (of the cyanide complex) NMR studies together with proton NMR studies of the native and cyanide-complexed Caprinus peroxidase are consistent with coordination of a proximal histidine ligand. The EPR spectrum of the ferrous NO complex is also reported. Protein reconstitution with deuterated hemin has facilitated the assignment of the heme methyl resonances in the proton NMR spectrum

  15. 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)

  16. Leishmania mexicana amazonensis: heterogeneity in 5-nucleotidase and peroxidase activities of mononuclear phagocytes during in vivo and in vitro infection

    OpenAIRE

    Côrte-Real, Suzana; Grimaldi Junior, Gabriel; Meirelles, Maria de Nazareth Leal de

    1988-01-01

    The degree of maturation of cells of the Mononuclear Phagocyte System (MPS), during in vivo and in vitro infection by Leishmania mexicana amazonenesis, was evaluated in this study. The macrophages' differentiation was assayed by cytochemical characterization at the ultrastrctural level, using two well-established markers: 5'-nucleotidase enzyme activity, for revealing the mature cells, and the peroxidase activity present in the cell granules to demonstrate immature mononuclear phagocytes. onl...

  17. Photoperiodism and Enzyme Activity

    Science.gov (United States)

    Queiroz, Orlando; Morel, Claudine

    1974-01-01

    Metabolic readjustments after a change from long days to short days appear, in Kalanchoe blossfeldiana, to be achieved through the operation of two main mechanisms: variation in enzyme capacity, and circadian rhythmicity. After a lag time, capacity in phosphoenolpyruvate carboxylase and capacity in aspartate aminotransferase increase exponentially and appear to be allometrically linked during 50 to 60 short days; then a sudden fall takes place in the activity of the former. Malic enzyme and alanine aminotransferase behave differently. Thus, the operation of the two sections of the pathway (before and after the malate step) give rise to a continuously changing functional compartmentation in the pathway. Circadian rhythmicity, on the other hand, produces time compartmentation through phase shifts and variation in amplitude, independently for each enzyme. These characteristics suggest that the operation of a so-called biological clock would be involved. We propose the hypothesis that feedback regulation would be more accurate and efficient when applied to an already oscillating, clock-controlled enzyme system. PMID:16658749

  18. Catalase and ascorbate peroxidase-representative H2O2-detoxifying heme enzymes in plants.

    Science.gov (United States)

    Anjum, Naser A; Sharma, Pallavi; Gill, Sarvajeet S; Hasanuzzaman, Mirza; Khan, Ekhlaque A; Kachhap, Kiran; Mohamed, Amal A; Thangavel, Palaniswamy; Devi, Gurumayum Devmanjuri; Vasudhevan, Palanisamy; Sofo, Adriano; Khan, Nafees A; Misra, Amarendra Narayan; Lukatkin, Alexander S; Singh, Harminder Pal; Pereira, Eduarda; Tuteja, Narendra

    2016-10-01

    Plants have to counteract unavoidable stress-caused anomalies such as oxidative stress to sustain their lives and serve heterotrophic organisms including humans. Among major enzymatic antioxidants, catalase (CAT; EC 1.11.1.6) and ascorbate peroxidase (APX; EC 1.11.1.11) are representative heme enzymes meant for metabolizing stress-provoked reactive oxygen species (ROS; such as H2O2) and controlling their potential impacts on cellular metabolism and functions. CAT mainly occurs in peroxisomes and catalyzes the dismutation reaction without requiring any reductant; whereas, APX has a higher affinity for H2O2 and utilizes ascorbate (AsA) as specific electron donor for the reduction of H2O2 into H2O in organelles including chloroplasts, cytosol, mitochondria, and peroxisomes. Literature is extensive on the glutathione-associated H2O2-metabolizing systems in plants. However, discussion is meager or scattered in the literature available on the biochemical and genomic characterization as well as techniques for the assays of CAT and APX and their modulation in plants under abiotic stresses. This paper aims (a) to introduce oxidative stress-causative factors and highlights their relationship with abiotic stresses in plants; (b) to overview structure, occurrence, and significance of CAT and APX in plants; (c) to summarize the principles of current technologies used to assay CAT and APX in plants; (d) to appraise available literature on the modulation of CAT and APX in plants under major abiotic stresses; and finally, (e) to consider a brief cross-talk on the CAT and APX, and this also highlights the aspects unexplored so far.

  19. Peroxidase synthesis and activity in the interaction of soybean with Phytophthora megasperma f. sp. glycinea (Pmg)

    International Nuclear Information System (INIS)

    Chibbar, R.N.; Esnault, R.; Lee, D.; van Huystee, R.B.; Ward, E.W.B.

    1986-01-01

    Changes, in peroxidase (EC1.11.1.7) have been reported following infection. However, determinations of biosynthesis of quantities of the peroxidase protein molecule have not been made! In this study hypocotyl of soybean seedlings (Glycine max; cv Harosoy, susceptible; cv Harosoy 63, resistant) were inoculated with zoospores of Pmg. Incorporation of 35 S-methionine (supplied with inoculum) in TCA precipitates was measured. Peroxidase synthesis was measured by immuno precipitation using antibodies against a cationic and an anionic peroxidase derived from peanut cells. Specific peroxidase activity increased rapidly from 5 to 9 h following infection in the resistant reaction but not in the susceptible reaction or the water controls. There was increased synthesis of the anionic peroxidase but not of the cationic peroxidase in the resistant reaction. The anionic peroxidase did not increase in the susceptible until 15 h. The ratio of peroxidase synthesis to total protein synthesis decreased in inoculated tissues compared to control. Peroxidase synthesis is, therefore, a relative minor host response to infection

  20. Development of horseradish peroxidase-based cross-linked enzyme aggregates and their environmental exploitation for bioremediation purposes.

    Science.gov (United States)

    Bilal, Muhammad; Iqbal, Hafiz M N; Hu, Hongbo; Wang, Wei; Zhang, Xuehong

    2017-03-01

    In the present study, horseradish peroxidase (HRP), in-house isolated crude cocktail enzyme, from Armoracia rusticana was cross-linked using a new type of cross-linking agent, i.e., ethylene glycol-bis [succinic acid N-hydroxysuccinimide, (EG-NHS)], which is mild in nature as compared to the glutaraldehyde (GA). The HRP-immobilized cross-linked enzyme aggregates (HRP-CLEAs) were developed using a wider range of EG-NHS and notably no adverse effect was observed. In a comparative evaluation, in the case of EG-NHS, a high-level stability in the residual activity was recorded, whereas a sharp decrease was observed in the case of glutaraldehyde. Following initial cross-linker evaluation, the HRP-CLEAs were tested to investigate their bio-catalytic efficacy for bioremediation purposes using a newly developed packed bed reactor system (PBRS). A maximal of 94.26% degradation of textile-based methyl orange dye was recorded within the shortest time frame, following 91.73% degradation of basic red 9, 84.35% degradation of indigo, 81.47% degradation of Rhodamin B, and 73.6% degradation of Rhodamine 6G, respectively, under the same working environment. Notably, the HRP-CLEAs retained almost 60% of its original activity after methyl orange dye degradation in seven consecutive cycles using PBRS. Furthermore, after HRP-CLEAs-mediated treatment in the PBRS, a significant toxicity reduction in the dye samples was recorded as compared to their pristine counterparts. In conclusion, the results suggest that the newly developed HRP-CLEAs have a great potential for industrial exploitation, to tackle numerous industrial dye-based emergent pollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Chaperone-Like Activity of ß-Casein and Its Effect on Residual in Vitro Activity of Food Enzymes

    DEFF Research Database (Denmark)

    Sulewska, Anna Maria

    ABSTRACT Activity of endogenous enzymes may cause browning of fruits and vegetables. These enzymes can be inactivated, for example by heat treatment, but the response of enzymes to heat treatment depends on many factors. Foods are very complex systems and the stability of enzymes......-casein on the enzymatic activity of three targets was tested by monitoring enzyme activity after heat treatment and by measuring the intensity of scattered light during and after heat treatment. β-Casein was shown to interact at elevated temperatures with three selected targets:horseradish peroxidase, tyrosinase from......, residual activity of horseradish peroxidase was lower in samples containing BSA than in samples without any addition. Horseradish peroxidase heated with BSA did not regain activity within one hour after treatment. BSA is often added to enzyme solutions to prevent enzyme adhesion to vial surfaces...

  2. Effects of topical vitamin E on corneal superoxide dismutase, glutathione peroxidase activities and polymorphonuclear leucocyte infiltration after photorefractive keratectomy.

    Science.gov (United States)

    Bilgihan, Ayse; Bilgihan, Kamil; Yis, Ozgür; Sezer, Cem; Akyol, Gülen; Hasanreisoglu, Berati

    2003-04-01

    Photorefractive keratectomy (PRK) induces free radical formation and polymorphonuclear (PMN) cell infiltration in the cornea. Vitamin E is a free radical scavenger and protects the cells from reactive oxygen species. We investigated the effects of topical vitamin E on corneal PMN cell infiltration and corneal antioxidant enzyme activities after PRK. We studied four groups, each consisting of seven eyes. Group 1 were control eyes. In group 2 the corneal epithelium was removed by a blunt spatula (epithelial scrape). In group 3, corneal photoablation (59 micro m, 5 dioptres) was performed after epithelial removal (traditional PRK). In group 4 we tested the effects of topical Vitamin E after traditional PRK. Corneal tissues were removed and studied with enzymatic analysis (measurement of corneal superoxide dismutase and glutathione peroxidase activities) and histologically. Stromal PMN leucocyte counts were significantly higher after mechanical epithelial removal and traditional PRK (p < 0.05). Corneal superoxide dismutase and glutathione peroxidase activities decreased significantly after mechanical epithelial removal and traditional PRK (p < 0.05). In group 4, treated with vitamin E, corneal superoxide dismutase activity did not differ significantly from that in the medically non-treated groups, nor did corneal PMN cell infiltration after traditional PRK. The reduction of corneal glutathione peroxidase activity after PRK was reduced significantly after topical vitamin E treatment. Topical vitamin E treatment may be useful for reducing the harmful effects of reactive oxygen radical after epithelial scraping and PRK in that it increases corneal glutathione peroxidase activity.

  3. Online Detection of Peroxidase Using 3D Printing, Active Magnetic Mixing, and Spectra Analysis

    Directory of Open Access Journals (Sweden)

    Shanshan Bai

    2017-01-01

    Full Text Available A new method for online detection of peroxidase (POD using 3D printing, active magnetic mixing, fluidic control, and optical detection was developed and demonstrated in this study. The proposed POD detection system consisted of a 3D printing and active magnetic mixing based fluidic chip for online catalytic reaction, an optical detector with a fluidic flow cell for quantitative determination of the final catalysate, and a single-chip microcontroller based controller for automatic control of two rotating magnetic fields and four precise peristaltic pumps. Horseradish peroxidase (HRP was used as research model and a linear relationship between the absorbance at the characteristic wavelength of 450 nm and the concentration of HRP of 1/4–1/128 μg mL−1 was obtained as A  =  0.257ln⁡(C + 1.425 (R2  = 0.976. For the HRP spiked pork tests, the recoveries of HRP ranged from 93.5% to 110.4%, indicating that this proposed system was capable of detecting HRP in real samples. It has the potential to be extended for online detection of the activity of other enzymes and integration with ELISA method for biological and chemical analysis.

  4. Peroxidase-like activity of nanocrystalline cobalt selenide and its application for uric acid detection

    Directory of Open Access Journals (Sweden)

    Zhuang QQ

    2017-04-01

    Full Text Available Quan-Quan Zhuang,1 Zhi-Hang Lin,1 Yan-Cheng Jiang,1 Hao-Hua Deng,2 Shao-Bin He,1,3 Li-Ting Su,4 Xiao-Qiong Shi,2 Wei Chen2 1Department of Pharmacy, Affiliated Quanzhou First Hospital of Fujian Medical University, Quanzhou, 2Department of Pharmaceutical Analysis, School of Pharmacy, Fujian Medical University, Fuzhou, 3Department of Pharmacy, Quanzhou Infectious Disease Hospital, 4Department of Pharmaceutical Analysis, Quanzhou Medical College, Quanzhou, People’s Republic of China Abstract: Dendrite-like cobalt selenide nanostructures were synthesized from cobalt and selenium powder precursors by a solvothermal method in anhydrous ethylenediamine. The as-prepared nanocrystalline cobalt selenide was found to possess peroxidase-like activity that could catalyze the reaction of peroxidase substrates in the presence of H2O2. A spectrophotometric method for uric acid (UA determination was developed based on the nanocrystalline cobalt selenide-catalyzed coupling reaction between N-ethyl-N-(3-sulfopropyl-3-methylaniline sodium salt and 4-aminoantipyrine (4-AAP in the presence of H2O2. Under optimum conditions, the absorbance was proportional to the concentration of UA over the range of 2.0–40 µM with a detection limit of 0.5 µM. The applicability of the proposed method has been validated by determination of UA in human serum samples with satisfactory results. Keywords: enzyme mimics, cobalt selenide, peroxidase-like activity, uric acid, human serum

  5. Competitive photometric enzyme immunoassay for fullerene C60 and its derivatives using a fullerene conjugated to horseradish peroxidase

    International Nuclear Information System (INIS)

    Hendrickson, Olga D.; Smirnova, Natalya I.; Zherdev, Anatoly V.; Dzantiev, Boris B.; Sveshnikov, Peter G.

    2016-01-01

    The article describes a highly sensitive single-step microplate enzyme immunoassay of the ELISA type for fullerene C 60 and its derivatives. Monoclonal anti-fullerene antibodies and a conjugate between fullerene and horseradish peroxidase were used as specific reagents. A direct competitive ELISA was carried out that was based on antibodies immobilized in the well of a microtiter plate, a peroxidase-labeled antigen, and detection via the dye formed from 3,3′,5,5′-tetramethylbenzidine and hydrogen peroxide. Both pristine fullerene C 60 and its water-soluble forms can be determined. The detection limits are 1.5 ng∙mL −1 for fullerene C 60 , and between 0.1 and 1.3 ng∙mL −1 for its derivatives. This ELISA format allows for almost two-fold reduction of the time needed for the assay in comparison to indirect scheme with labeled antibodies. (author)

  6. Prostaglandin endoperoxide H synthases: peroxidase hydroperoxide specificity and cyclooxygenase activation.

    Science.gov (United States)

    Liu, Jiayan; Seibold, Steve A; Rieke, Caroline J; Song, Inseok; Cukier, Robert I; Smith, William L

    2007-06-22

    The cyclooxygenase (COX) activity of prostaglandin endoperoxide H synthases (PGHSs) converts arachidonic acid and O2 to prostaglandin G2 (PGG2). PGHS peroxidase (POX) activity reduces PGG2 to PGH2. The first step in POX catalysis is formation of an oxyferryl heme radical cation (Compound I), which undergoes intramolecular electron transfer forming Intermediate II having an oxyferryl heme and a Tyr-385 radical required for COX catalysis. PGHS POX catalyzes heterolytic cleavage of primary and secondary hydroperoxides much more readily than H2O2, but the basis for this specificity has been unresolved. Several large amino acids form a hydrophobic "dome" over part of the heme, but when these residues were mutated to alanines there was little effect on Compound I formation from H2O2 or 15-hydroperoxyeicosatetraenoic acid, a surrogate substrate for PGG2. Ab initio calculations of heterolytic bond dissociation energies of the peroxyl groups of small peroxides indicated that they are almost the same. Molecular Dynamics simulations suggest that PGG2 binds the POX site through a peroxyl-iron bond, a hydrogen bond with His-207 and van der Waals interactions involving methylene groups adjoining the carbon bearing the peroxyl group and the protoporphyrin IX. We speculate that these latter interactions, which are not possible with H2O2, are major contributors to PGHS POX specificity. The distal Gln-203 four residues removed from His-207 have been thought to be essential for Compound I formation. However, Q203V PGHS-1 and PGHS-2 mutants catalyzed heterolytic cleavage of peroxides and exhibited native COX activity. PGHSs are homodimers with each monomer having a POX site and COX site. Cross-talk occurs between the COX sites of adjoining monomers. However, no cross-talk between the POX and COX sites of monomers was detected in a PGHS-2 heterodimer comprised of a Q203R monomer having an inactive POX site and a G533A monomer with an inactive COX site.

  7. Sex determines the influence of smoking and gene polymorphism on glutathione peroxidase activity in erythrocytes

    DEFF Research Database (Denmark)

    Malling, Tine Halsen; Sigsgaard, Torben; Andersen, Helle Raun

    2009-01-01

    OBJECTIVE: Glutathione peroxidase 1 (GPX1) is one of the major oxidative enzymes. Our aim was to characterize factors influencing its activity and to determine whether or not the activity is associated with asthma. MATERIAL AND METHODS: Serum selenium concentration was measured, GPX1 polymorphisms...... %) had doctor-diagnosed asthma. RESULTS: The average serum selenium concentration was too low for optimal enzyme activity (mean (SE), 83.4 (0.76) ng/mL). GPX1 activity in men was lower than in women, 52.6 (0.66) and 56.4 (0.59) U/g protein, respectively (p... associated with serum selenium concentration (p = 0.005) and negatively associated with both active smoking (p = 0.009) and exposure to environmental tobacco smoke (p = 0.02). In women, activity was associated with genotypes with 59.2 (1.4), 56.0 (1.4) and 54.2 (1.4) U/g protein in the homozygote wild...

  8. Cu–hemin metal-organic frameworks with peroxidase-like activity as peroxidase mimics for colorimetric sensing of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fenfen; He, Juan; Zeng, Mulang; Hao, Juan; Guo, Qiaohui; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, College of Chemistry and Chemical Engineering (China)

    2016-05-15

    In this work, a facile strategy to synthesize Cu–hemin metal-organic frameworks (MOFs) with peroxidase-like activity was reported. The prepared Cu–hemin MOFs were characterized by various techniques such as scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, UV–visible absorbance spectra, and so on. The results showed that the prepared Cu–hemin MOFs looked like a ball-flower with an average diameter of 10 μm and provided a large specific surface area. The Cu–hemin MOFs possessing peroxidase-like activity could be used to catalyze the peroxidase substrate of 3,3,5,5-tetramethylbenzidine in the presence of H{sub 2}O{sub 2}, which was employed to detect H{sub 2}O{sub 2} quantitatively with the linear range from 1.0 μM to 1.0 mM and the detection limit was 0.42 μM. Furthermore, with the additional help of glucose oxidase, a sensitive and selective method to detect glucose was developed by using the Cu–hemin MOFs as catalyst and the linear range was from 10.0 μM to 3.0 mM and the detection limit was 6.9 μM. This work informs researchers of the advantages of MOFs for preparing biomimetic catalysts and extends the functionality of MOFs for biosensor application.Graphical Abstract.

  9. Strand displacement activated peroxidase activity of hemin for fluorescent DNA sensing.

    Science.gov (United States)

    Wang, Quanbo; Xu, Nan; Gui, Zhen; Lei, Jianping; Ju, Huangxian; Yan, Feng

    2015-10-07

    To efficiently regulate the catalytic activity of the peroxidase mimic hemin, this work designs a double-stranded DNA probe containing an intermolecular dimer of hemin, whose peroxidase activity can be activated by a DNA strand displacement reaction. The double-stranded probe is prepared by annealing two strands of hemin labelled DNA oligonucleotides. Using the fluorescent oxidation product of tyramine by H2O2 as a tracing molecule, the low peroxidase activity of the hemin dimer ensures a low fluorescence background. The strand displacement reaction of the target DNA dissociates the hemin dimer and thus significantly increases the catalytic activity of hemin to produce a large amount of dityramine for fluorescence signal readout. Based on the strand displacement regulated peroxidase activity, a simple and sensitive homogeneous fluorescent DNA sensing method is proposed. The detection can conveniently be carried out in a 96-well plate within 20 min with a detection limit of 0.18 nM. This method shows high specificity, which can effectively distinguish single-base mismatched DNA from perfectly matched target DNA. The DNA strand displacement regulated catalytic activity of hemin has promising application in the determination of various DNA analytes.

  10. Molecular Modeling of Peroxidase and Polyphenol Oxidase: Substrate Specificity and Active Site Comparison

    Directory of Open Access Journals (Sweden)

    Lalida Shank

    2010-09-01

    Full Text Available Peroxidases (POD and polyphenol oxidase (PPO are enzymes that are well known to be involved in the enzymatic browning reaction of fruits and vegetables with different catalytic mechanisms. Both enzymes have some common substrates, but each also has its specific substrates. In our computational study, the amino acid sequence of grape peroxidase (ABX was used for the construction of models employing homology modeling method based on the X-ray structure of cytosolic ascorbate peroxidase from pea (PDB ID:1APX, whereas the model of grape polyphenol oxidase was obtained directly from the available X-ray structure (PDB ID:2P3X. Molecular docking of common substrates of these two enzymes was subsequently studied. It was found that epicatechin and catechin exhibited high affinity with both enzymes, even though POD and PPO have different binding pockets regarding the size and the key amino acids involved in binding. Predicted binding modes of substrates with both enzymes were also compared. The calculated docking interaction energy of trihydroxybenzoic acid related compounds shows high affinity, suggesting specificity and potential use as common inhibitor to grape ascorbate peroxidase and polyphenol oxidase.

  11. 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. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. EVALUATION OF ENDOGLUCANASE, EXOGLUCANASE, LACCASE, AND LIGNIN PEROXIDASE ACTIVITIES ON TEN WHITE-ROT FUNGI

    Directory of Open Access Journals (Sweden)

    Sandra Montoya B

    2014-12-01

    Full Text Available This paper presents a way of tracking the production of lignocellulolytic enzymes in ten species of white rot fungi: Lentinula edodes, Schizophyllum commune, Trametes trogii, Coriolus versicolor, Pycnoporus sanguineus, Ganoderma applanatum, Ganoderma lucidum, Grifola frondosa, Pleurotus ostreatus and Auricularia delicata. These species were first screened on solid culture media containing carboxymethyl cellulose, crystalline cellulose, ABTS (2,2´-azino-bis(3-ethylbenzothiazoline-6-sulphonate and azure B, which showed the production of endoglucanase, exoglucanase, laccase and lignin peroxidase (LiP enzymes. Cellulolytic activities were detected after five days of incubation with congo red indicator, forming a clear-white halo in areas where cellulose was degraded. For ligninases, the tracking consisted of the monitoring in the formation of green halos due to ABTS oxidation for laccase, and decolorization halos on azure B for LiP during 14 days of incubation. From this qualitative screening, four strains were selected (G. lucidum, L. edodes, C. versicolor and T. trogii as the best producers of cellulolytic and ligninolytic enzymes. These four species were inoculated on a substrate of sawdust oak, yielding 51,8% of lignin degraded by L. edodes and 22% of cellulose degraded by C. versicolor.

  13. Construction and Characterization of Vitreoscilla Hemoglobin (VHb) with Enhanced Peroxidase Activity for Efficient Degradation of Textile Dye.

    Science.gov (United States)

    Zhang, Zidong; Li, Wei; Li, Haichao; Zhang, Jing; Zhang, Yuebin; Cao, Yufeng; Ma, Jianzhang; Li, Zhengqiang

    2015-09-01

    Pollution resulting from the discharge of textile dyes into water systems has become a major global concern. Because peroxidases are known for their ability to decolorize and detoxify textile dyes, the peroxidase activity of Vitreoscilla hemoglobin (VHb) has recently been studied. It is found that VHb and variants of this enzyme show great promise for enzymatic decolorization of dyes and may play a role in achieving their successful removal from industrial wastewater. The level of VHb peroxidase activity correlates with two amino acid residues present within the conserved distal pocket, at positions 53 and 54. In this work, sitedirected mutagenesis of these residues was performed and resulted in improved VHb peroxidase activity. The double mutant, Q53H/P54C, shows the highest dye decolorization and removal efficiency, with 70% removal efficiency within 5 min. UV spectral studies of Q53H/P54C reveals a more compact structure and an altered porphyrin environment (λSoret = 413 nm) relative to that of wild-type VHb (λSoret = 406), and differential scanning calorimetry data indicate that the VHb variant protein structure is more stable. In addition, circular dichroism spectroscopic studies indicate that this variant's increased protein structural stability is due to an increase in helical structure, as deduced from the melting temperature, which is higher than 90°C. Therefore, the VHb variant Q53H/P54C shows promise as an excellent peroxidase, with excellent dye decolorization activity and a more stable structure than wild-type VHb under high-temperature conditions.

  14. Effective Peroxidase-Like Activity of Co-Aminoclay [CoAC] and Its Application for Glucose Detection

    Directory of Open Access Journals (Sweden)

    Han Pill Song

    2018-02-01

    Full Text Available In this study, we describe a novel peroxidase-like activity of Co-aminoclay [CoAC] present at pH ~5.0 and its application to fluorescent biosensor for the determination of H2O2 and glucose. It is synthesized with aminoclays (ACs entrapping cationic metals such as Fe, Cu, Al, Co., Ce, Ni, Mn, and Zn to find enzyme mimicking ACs by sol–gel ambient conditions. Through the screening of catalytic activities by the typical colorimetric reaction employing 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic aciddiammonium salt (ABTS as a substrate with or without H2O2, Fe, Cu, and CoACs are found to exhibit peroxidase-like activity, as well as oxidase-like activity was observed from Ce and MnACs. Among them, CoAC shows exceptionally high peroxidase-like activity, presumably due to its ability to induce electron transfer between substrates and H2O2. CoAC is then used to catalyze the oxidation of Amplex® UltraRed (AUR into a fluorescent end product, which enables a sensitive fluorescent detection of H2O2. Moreover, a highly sensitive and selective glucose biosensing strategy is developed, based on enzyme cascade reaction between glucose oxidase (GOx and CoAC. Using this strategy, a highly linear fluorescence enhancement is verified when the concentration of glucose is increased in a wide range from 10 μM to 1 mM with a lower detection limit of 5 μM. The practical diagnostic capability of the assay system is also verified by its use to detect glucose in human blood serum. Based on these results, it is anticipated that CoAC can serve as potent peroxidase mimetics for the detection of clinically important target molecules.

  15. Insight into the mechanism revealing the peroxidase mimetic catalytic activity of quaternary CuZnFeS nanocrystals: colorimetric biosensing of hydrogen peroxide and glucose

    Science.gov (United States)

    Dalui, Amit; Pradhan, Bapi; Thupakula, Umamahesh; Khan, Ali Hossain; Kumar, Gundam Sandeep; Ghosh, Tanmay; Satpati, Biswarup; Acharya, Somobrata

    2015-05-01

    Artificial enzyme mimetics have attracted immense interest recently because natural enzymes undergo easy denaturation under environmental conditions restricting practical usefulness. We report for the first time chalcopyrite CuZnFeS (CZIS) alloyed nanocrystals (NCs) as novel biomimetic catalysts with efficient intrinsic peroxidase-like activity. Novel peroxidase activities of CZIS NCs have been evaluated by catalytic oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). CZIS NCs demonstrate the synergistic effect of elemental composition and photoactivity towards peroxidase-like activity. The quaternary CZIS NCs show enhanced intrinsic peroxidase-like activity compared to the binary NCs with the same constituent elements. Intrinsic peroxidase-like activity has been correlated with the energy band position of CZIS NCs extracted using scanning tunneling spectroscopy and ultraviolet photoelectron spectroscopy. Kinetic analyses indicate Michaelis-Menten enzyme kinetic model catalytic behavior describing the rate of the enzymatic reaction by correlating the reaction rate with substrate concentration. Typical color reactions arising from the catalytic oxidation of TMB over CZIS NCs with H2O2 have been utilized to establish a simple and sensitive colorimetric assay for detection of H2O2 and glucose. CZIS NCs are recyclable catalysts showing high efficiency in multiple uses. Our study may open up the possibility of designing new photoactive multi-component alloyed NCs as enzyme mimetics in biotechnology applications.Artificial enzyme mimetics have attracted immense interest recently because natural enzymes undergo easy denaturation under environmental conditions restricting practical usefulness. We report for the first time chalcopyrite CuZnFeS (CZIS) alloyed nanocrystals (NCs) as novel biomimetic catalysts with efficient intrinsic peroxidase-like activity. Novel peroxidase activities of CZIS NCs have been

  16. Luffa aegyptiaca (Gourd) Fruit Juice as a Source of Peroxidase

    OpenAIRE

    Yadav, R. S. S.; Yadav, K. S.; Yadav, H. S.

    2011-01-01

    Peroxidases have turned out to be potential biocatalyst for a variety of organic reactions. The research work reported in this communication was done with the objective of finding a convenient rich source of peroxidase which could be used as a biocatalyst for organic synthetic reactions. The studies made have shown that Luffa aegyptiaca (gourd) fruit juice contains peroxidase activity of the order of 180 enzyme unit/mL. The K m values of this peroxidase for the substrates guaiacol and hydroge...

  17. Chaperone-like activity of β-casein and its effect on residual in vitro activity of horseradish peroxidase

    DEFF Research Database (Denmark)

    Sulewska, Anna Maria; Olsen, Karsten; Sørensen, Jens Christian

    2014-01-01

    , as similar experiment with bovine serum albumin resulted in residual activity of horseradish peroxidase that was significantly lower than without any addition. The effect of β-casein on HRP disappears when pH is below the isoelectric point of β-casein. It was also proven by light scattering studies that β...... proteins. Incubating HRP (0.1 mg mL-1) for 10 min at 72 °C resulted in residual activity of 59 ± 5%, while addition of 1 mg mL-1 β-casein resulted in increase in residual activity up to 85 ± 1%. Increased residual activity is not merely attributed to an effect of higher total protein concentration......-casein interacts with horseradish peroxidase when the temperature was increased from 25 to 70 °C whereas interactions seem to cease when temperature was lowered back to 25 °C. This study highlights how specific proteins can influence enzyme activity, which is of potential importance for various industries...

  18. Mutation of katG in a clinical isolate of Mycobacterium tuberculosis: effects on catalase-peroxidase for isoniazid activation.

    Science.gov (United States)

    Purkan; Ihsanawati; Natalia, D; Syah, Y M; Retnoningrum, D S; Kusuma, H S

    2016-01-01

    Mutations in katG gene are often associated with isoniazid (INH) resistance in Mycobacterium tuberculosis strain. This research was perfomed to identify the katG mutation in clinical isolate (L8) that is resistant to INH at 1 μg/ml. In addition to characterize the catalase-peroxidase of KatG L8 and perform the ab initio structural study of the protein to get a more complete understanding in drug activation and the resistan­ce mechanism. The katG gene was cloned and expressed in Escherichia coli, then followed by characterization of catalase-peroxidase of KatG. The structure modelling was performed to know a basis of alterations in enzyme activity. A substitution of A713G that correspond to Asn238Ser replacement was found in the L8 katG. The Asn238Ser modification leads to a decline in the activity of catalase-peroxidase and INH oxidation of the L8 KatG protein. The catalytic efficiency (Kcat/KM) of mutant KatGAsn238Ser respectively decreases to 41 and 52% for catalase and peroxidase. The mutant KatGAsn238Ser also shows a decrease of 62% in INH oxidation if compared to a wild type KatG (KatGwt). The mutant Asn238Ser might cause instability in the substrate binding­ site of KatG, because of removal of a salt bridge connecting the amine group of Asn238 to the carbo­xyl group of Glu233, which presents in KatGwt. The lost of the salt bridge in the substrate binding site in mutant KatGAsn238Ser created changes unfavorable for enzyme activities, which in turn emerge as INH resistan­ce in the L8 isolate of M. tuberculosis.

  19. Improved activity of immobilized horseradish peroxidase on gold nanoparticles in the presence of bovine serum albumin

    International Nuclear Information System (INIS)

    Ni, Yuyang; Li, Jun; Huang, Zhenzhen; He, Ke; Zhuang, Jiaqi; Yang, Wensheng

    2013-01-01

    The using of macromolecular additives is known to be a simple and effective way to improve the activity of immobilized enzymes on solid support, yet the mechanism has not been well understood. Taking horseradish peroxidase (HRP) as an example, only 30 % of its catalytic activity was kept after being immobilized on the surface of 25-nm Au nanoparticles, mainly attributed to the conformational change of the heme-containing active site. The catalytic activity of HRP was significantly improved to 80 % when a certain amount of bovine serum albumin (BSA) was added at the initial stage of the immobilization. Systematic spectral investigation indicated that the addition of BSA inhibited the tertiary structure change around the active site, which was a prerequisite for improved activity of the immobilized HRP. Steady-state kinetic analyses revealed that the introduction of BSA could effectively improve the turnover rate of substrate to product in spite of slight reduced affinity to substrates, which also contributed to the improved catalytic activity

  20. Magnetic Fe3S4 nanoparticles with peroxidase-like activity, and their use in a photometric enzymatic glucose assay

    International Nuclear Information System (INIS)

    Ding, Caiping; Yan, Yinghan; Zhang, Cuiling; Xian, Yuezhong; Xiang, Dongshan

    2016-01-01

    Greigite magnetic nanoparticles (Fe 3 S 4 -MNPs) were prepared and reveal a peroxidase-like activity. Kinetic studies revealed a pseudo-enzymatic activity that is much higher than that of other magnetic nanomaterial-based enzyme mimetics. This finding was exploited to design a photometric enzymatic glucose assay based on the formation of H 2 O 2 during enzymatic oxidation of glucose by glucose oxidase, and the formation of a blue product from an enzyme substrate that is catalytically oxidized by H 2 O 2 in the presence of Fe 3 S 4 -MNPs. Glucose can be detected in the 2 to 100 μM concentration range, and the low detection limit is 0.16 μM. The method was applied to quantify glucose in human serum. In our perception, this enzyme mimetic has a large potential in that it may be used in other oxidase based assays, but also in ELISAs. (author)

  1. Paper Microzone Plates as Analytical Tools for Studying Enzyme Stability: A Case Study on the Stabilization of Horseradish Peroxidase Using Trehalose and SU-8 Epoxy Novolac Resin.

    Science.gov (United States)

    Ganaja, Kirsten A; Chaplan, Cory A; Zhang, Jingyi; Martinez, Nathaniel W; Martinez, Andres W

    2017-05-16

    Paper microzone plates in combination with a noncontact liquid handling robot were demonstrated as tools for studying the stability of enzymes stored on paper. The effect of trehalose and SU-8 epoxy novolac resin (SU-8) on the stability of horseradish peroxidase (HRP) was studied in both a short-term experiment, where the activity of various concentrations of HRP dried on paper were measured after 1 h, and a long-term experiment, where the activity of a single concentration of HRP dried and stored on paper was monitored for 61 days. SU-8 was found to stabilize HRP up to 35 times more than trehalose in the short-term experiment for comparable concentrations of the two reagents, and a 1% SU-8 solution was found to stabilize HRP approximately 2 times more than a 34% trehalose solution in both short- and long-term experiments. The results suggest that SU-8 is a promising candidate for use as an enzyme-stabilizing reagent for paper-based diagnostic devices and that the short-term experiment could be used to quickly evaluate the capacity of various reagents for stabilizing enzymes to identify and characterize new enzyme-stabilizing reagents.

  2. Temperature dependence of the activity of polyphenol peroxidases and polyphenol oxidases in modern and buried soils

    Science.gov (United States)

    Yakushev, A. V.; Kuznetsova, I. N.; Blagodatskaya, E. V.; Blagodatsky, S. A.

    2014-05-01

    Under conditions of the global climate warming, the changes in the reserves of soil humus depend on the temperature sensitivities of polyphenol peroxidases (PPPOs) and polyphenol oxidases (PPOs). They play an important role in lignin decomposition, mineralization, and humus formation. The temperature dependence of the potential enzyme activity in modern and buried soils has been studied during incubation at 10 or 20°C. The experimental results indicate that it depends on the availability of the substrate and the presence of oxygen. The activity of PPOs during incubation in the absence of oxygen for two months decreases by 2-2.5 times, which is balanced by an increase in the activity of PPPOs by 2-3 times. The increase in the incubation temperature to 20°C and the addition of glucose accelerates this transition due to the more abrupt decrease in the activity of PPOs. The preincubation of the soil with glucose doubles the activity of PPPOs but has no significant effect on the activity of PPOs. The different effects of temperature on two groups of the studied oxidases and the possibility of substituting enzymes by those of another type under changing aeration conditions should be taken into consideration in predicting the effect of the climate warming on the mineralization of the soil organic matter. The absence of statistically significant differences in the enzymatic activity between the buried and modern soil horizons indicates the retention by the buried soil of some of its properties (soil memory) and the rapid restoration of high enzymatic activity during the preincubation.

  3. Calcium carbonate mediates higher lignin peroxidase activity in the culture supernatant of Streptomyces Viridosporus T7A

    Directory of Open Access Journals (Sweden)

    J. M. B. MACEDO

    1999-06-01

    Full Text Available Lignin peroxidase (LiP production has been extensively studied due to the potential use of this enzyme in environmental pollution control. Important aspects of the production of the enzyme by S. viridosporus T7A which have been studied include the improvement of yield and enzyme stabilization. In experiments performed in agitated flasks containing culture media composed of yeast extract as the source of nitrogen, mineral salts and different carbon sources, the use of glucose resulted in the highest values for LiP activity (350 U/L, specific LiP activity (450 U/g and productivity (7 U/L/h. As the profile obtained with glucose-containing medium suggested enzyme instability, the effect of calcium carbonate was evaluated. The addition of CaCO3 in two different concentrations, 0.5% and 5.0%, resulted in higher values of maximum LiP activity, 600 and 900 U/L, respectively. The presence of this salt also anticipated enzyme activity peaks and allowed the detection of higher enzyme activities in the extracellular medium for longer periods of time. These results indicate a positive effect of calcium carbonate on LiP production, which is extremely relevant for industrial processes.

  4. Formation of a tyrosine adduct involved in lignin degradation by Trametopsis cervina lignin peroxidase: a novel peroxidase activation mechanism

    Science.gov (United States)

    Yuta Miki; Rebecca Pogni; Sandra Acebes; Fatima Lucas; Elena Fernandez-Fueyo; Maria Camilla Baratto; Maria I. Fernandez; Vivian De Los Rios; Francisco J. Ruiz-duenas; Adalgisa Sinicropi; Riccardo Basosi; Kenneth E. Hammel; Victor Guallar; Angel T. Martinez

    2013-01-01

    LiP (lignin peroxidase) from Trametopsis cervina has an exposed catalytic tyrosine residue (Tyr181) instead of the tryptophan conserved in other lignin-degrading peroxidases. Pristine LiP showed a lag period in VA (veratryl alcohol) oxidation. However, VA-LiP (LiP after treatment with H2O2...

  5. Airway Peroxidases Catalyze Nitration of the β2-Agonist Salbutamol and Decrease Its Pharmacological Activity

    OpenAIRE

    Reszka, Krzysztof J.; Sallans, Larry; Macha, Stephen; Brown, Kari; McGraw, Dennis W.; Kovacic, Melinda Butsch; Britigan, Bradley E.

    2011-01-01

    β2-Agonists are the most effective bronchodilators for the rapid relief of asthma symptoms, but for unclear reasons, their effectiveness may be decreased during severe exacerbations. Because peroxidase activity and nitrogen oxides are increased in the asthmatic airway, we examined whether salbutamol, a clinically important β2-agonist, is subject to potentially inactivating nitration. When salbutamol was exposed to myeloperoxidase, eosinophil peroxidase or lactoperoxidase in the presence of hy...

  6. Nanodiamond-Gold Nanocomposites with the Peroxidase-Like Oxidative Catalytic Activity.

    Science.gov (United States)

    Kim, Min-Chul; Lee, Dukhee; Jeong, Seong Hoon; Lee, Sang-Yup; Kang, Eunah

    2016-12-21

    Novel nanodiamond-gold nanocomposites (NDAus) are prepared, and their oxidative catalytic activity is examined. Gold nanoparticles are deposited on carboxylated nanodiamonds (NDs) by in situ chemical reduction of gold precursor ions to produce NDAus, which exhibit catalytic activity for the oxidation of o-phenylenediamine in the presence of hydrogen peroxide similarly to a peroxidase. This remarkable catalytic activity is exhibited only by the gold nanoparticle-decorated NDs and is not observed for either Au nanoparticles or NDs separately. Kinetic oxidative catalysis studies show that NDAus exhibit a ping-pong mechanism with an activation energy of 93.3 kJ mol -1 , with the oxidation reaction rate being proportional to the substrate concentration. NDAus retain considerable activity even after several instances of reuse and are compatible with a natural enzyme, allowing the detection of xanthine using cascade catalysis. Association with gold nanoparticles makes NDs a good carbonic catalyst due to charge transfer at the metal-carbon interface and facilitated substrate adsorption. The results of this study suggest that diverse carbonic catalysts can be obtained by interfacial incorporation of various metal/inorganic substances.

  7. Structure-activity relationships and molecular docking of thirteen synthesized flavonoids as horseradish peroxidase inhibitors.

    Science.gov (United States)

    Mahfoudi, Reguia; Djeridane, Amar; Benarous, Khedidja; Gaydou, Emile M; Yousfi, Mohamed

    2017-10-01

    For the first time, the structure-activity relationships of thirteen synthesized flavonoids have been investigated by evaluating their ability to modulate horseradish peroxidase (HRP) catalytic activity. Indeed, a modified spectrophotometrically method was carried out and optimized using 4-methylcatechol (4-MC) as peroxidase co-substrate. The results show that these flavonoids exhibit a great capacity to inhibit peroxidase with Ki values ranged from 0.14±0.01 to 65±0.04mM. Molecular docking has been achieved using Auto Dock Vina program to discuss the nature of interactions and the mechanism of inhibition. According to the docking results, all the flavonoids have shown great binding affinity to peroxidase. These molecular modeling studies suggested that pyran-4-one cycle acts as an inhibition key for peroxidase. Therefore, potent peroxidase inhibitors are flavonoids with these structural requirements: the presence of the hydroxyl (OH) group in 7, 5 and 4' positions and the absence of the methoxy (O-CH 3 ) group. Apigenin contributed better in HRP inhibitory activity. The present study has shown that the studied flavonoids could be promising HRP inhibitors, which can help in developing new molecules to control thyroid diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Investigation of glutathione peroxidase activity in chicken meat under different experimental conditions

    Directory of Open Access Journals (Sweden)

    Alexandre José Cichoski

    2012-12-01

    Full Text Available Due to the fact that previous studies on the enzymatic activity of Glutathione peroxidase (GSH-Px diverge widely in their methodology and results, this study aimed to investigate the influence of different analytical conditions on GSH-Px activity in chicken thighs from broilers that were fed different diets with different sources and concentrations of selenium. GSH-Px activity was evaluated six hours after slaughter and 120 days after frozen storage at -18 ºC. The different analytical conditions included time of pre-incubation (0, 10 and 30 minutes, reaction medium, types of substrate (H2O2 (0.72 mM, 7.2 mM, and 72 mM and Terc-butil hydroperoxide 15 mM, and different buffer concentrations (buffer 1, potassium phosphate 50 mM pH 7.0 + EDTA 1 mM + mercaptoethanol 1 mM, and buffer 2, tris-HCl 50 mM pH 7.6 + EDTA 1 mM + mercapthanol 5 mM. The results show that the highest GSH-Px activity was observed when enzyme and substrate were in contact at 22 ºC without any pre-incubation, and that, when used at concentrations above 0.72 mM, hydrogen peroxide saturated the GSH-Px enzyme and inhibited its activity. The enzyme presented higher affinity to hydrogen peroxide when compared to terc-butil peroxide, and the addition of a buffer containing mercaptoethanol did not increase GSH-Px enzymatic activity. The activity of GSH-Px was not influenced by the source and concentration of selenium in the diet either. The obtained results allowed the determination of the best temperature of contact between the enzyme and substrate (22 ºC, the optimum concentration, and the type of substrate and buffer to be used. This information is extremely useful for future studies on GSH-Px activity in meat due to the divergence and little information found in the literature.

  9. The effect of intermittent hypobaric-hypoxia treatments on renal glutathione peroxidase activity of rats

    Science.gov (United States)

    Paramita, I. A.; Jusman, S. W. A.

    2017-08-01

    Many people living at high altitudes experiencing a condition called intermittent hypobaric hypoxia (IHH). Some people even create IHH condition as an exercise for pilots, athletes, and mountaineers. In this experiment, we aimed to determine whether the protective effect of IHH is mediated through glutathione peroxidase (GPX) enzyme. The experiment’s sample is two-month-old healthy Sprague-Dawley rat kidneys weighing 200-250 g. Intermittent hypobaric hypoxia treatment is done using a Hypobaric Chamber type I that can mimic air pressure at certain altitudes: 35,000 (one minute), 30,000 (three minutes), 25,000 (five minutes), and 18,000 (30 minutes) feet. The rats were divided into five treatment groups, including a control group, hypobaric-hypoxia group, and intermittent hypobaric-hypoxia 1x, 2x, and 3x groups with each group consisting of three rats. The specific activity of GPX was measured using RANDOX and RANSEL methods. The statistical analysis of one way-ANOVA did not show significant differences between the groups (p > 0.05), although specific activities of the renal GPX of rats exposed to hypobaric-hypoxia were higher than the control group. This may be caused by the other antioxidants’ activities. In conclusion, the IHH treatment did not affect GPX activity in the rat kidneys.

  10. Development of a thiol-ene based screening platform for enzyme immobilization demonstrated using horseradish peroxidase

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Pinelo, Manuel; Woodley, John

    2017-01-01

    Efficient immobilization of enzymes on support surfaces requires an exact match between the surface chemistry and the specific enzyme. A successful match would normally be identified through time consuming screening of conventional resins in multiple experiments testing individual immobilization...... strategies. In this study we present a versatile strategy that largely expands the number of possible surface functionalities for enzyme immobilization in a single, generic platform. The combination of many individual surface chemistries and thus immobilization methods in one modular system permits faster...... functionalization by thiol-ene chemistry (TEC) resulted in the formation of a functional monolayer in each well, whereas, polymer surface grafts were introduced through surface chain transfer free radical polymerization (SCT-FRP). Enzyme immobilization on the modified surfaces was evaluated by using a rhodamine...

  11. The Ustilago maydis effector Pep1 suppresses plant immunity by inhibition of host peroxidase activity.

    Directory of Open Access Journals (Sweden)

    Christoph Hemetsberger

    Full Text Available The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1 as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H₂O₂ strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction.

  12. Spectroscopic evidence for an engineered, catalytically active Trp radical that creates the unique reactivity of lignin peroxidase.

    Science.gov (United States)

    Smith, Andrew T; Doyle, Wendy A; Dorlet, Pierre; Ivancich, Anabella

    2009-09-22

    The surface oxidation site (Trp-171) in lignin peroxidase (LiP) required for the reaction with veratryl alcohol a high-redox-potential (1.4 V) substrate, was engineered into Coprinus cinereus peroxidase (CiP) by introducing a Trp residue into a heme peroxidase that has similar protein fold but lacks this activity. To create the catalytic activity toward veratryl alcohol in CiP, it was necessary to reproduce the Trp site and its negatively charged microenvironment by means of a triple mutation. The resulting D179W+R258E+R272D variant was characterized by multifrequency EPR spectroscopy. The spectra unequivocally showed that a new Trp radical [g values of g(x) = 2.0035(5), g(y) = 2.0027(5), and g(z) = 2.0022(1)] was formed after the [Fe(IV)=O Por(*+)] intermediate, as a result of intramolecular electron transfer between Trp-179 and the porphyrin. Also, the EPR characterization crucially showed that [Fe(IV)=O Trp-179(*)] was the reactive intermediate with veratryl alcohol. Accordingly, our work shows that it is necessary to take into account the physicochemical properties of the radical, fine-tuned by the microenvironment, as well as those of the preceding [Fe(IV)=O Por(*+)] intermediate to engineer a catalytically competent Trp site for a given substrate. Manipulation of the microenvironment of the Trp-171 site in LiP allowed the detection by EPR spectroscopy of the Trp-171(*), for which direct evidence has been missing so far. Our work also highlights the role of Trp residues as tunable redox-active cofactors for enzyme catalysis in the context of peroxidases with a unique reactivity toward recalcitrant substrates that require oxidation potentials not realized at the heme site.

  13. Peroxidase activity in roots of arracacha affected by pH and temperature = Atividade da peroxidase em raízes de batata-baroa afetada pelo pH e temperatura

    Directory of Open Access Journals (Sweden)

    Luciana Nunes Menolli

    2011-07-01

    Full Text Available In this paper, roots of arracacha (Arracacia xanthorrhyza Bancroft were stored at 5ºC to induce chilling injury symptoms and stress-related peroxidase activity. Later, peroxidase kinetic activity was determined in different pH and temperature conditions. For this, soluble crude extract was sequentially saturated with ammonium sulfate, obtaining a semi-purified enzyme solution used for the analysis. Activity of peroxidase induced by the chilling at 5oC was determined from pH 2.5 to 9.0 and at temperature ranging from 10 to80oC. The peroxidase had higher activity when the reaction occurred between pH 5.5 and 6.0 and at temperature of 30oC. Complete inactivation of the activity was observed in pH 2.5 after 60 minutes of pre-incubation or at 60oC for 10 minutes or alternatively at 70oCafter 5 minutes of pre-incubation. The enzyme is more susceptible to inactivation in acid than alkaline pHs or alternatively using heat treatment.Neste trabalho, raízes de batata-baroa (Arracacia xanthorrhiza Bancroft foram armazenadas a 5oC para induzir injúria por frio e expressar atividade da peroxidase de estresse. Posteriormente, a cinética de atividade foi determinada em diferentes condições depHs e temperatura. Para isto, extrato solúvel da raiz foi sequencialmente saturado com sulfato de amônio, obtendo-se uma preparação semi-purificada para a análise enzimática. Atividade peroxidativa induzida pela temperatura de armazenamento de 5oC foideterminada em pHs de 2,5 a 9,0 e a temperaturas de 10 a 80oC. A atividade da peroxidase foi maior quando a reação foi realizada nos pHs de 5,5 e 6,0 e temperatura de 30oC. A inativação completa da enzima ocorreu em pH de 2,5 após 60 min. de pré-incubação ou a60oC por 10 min., e alternativamente a 70oC após 5 min. de pré-incubação. A enzima foi mais susceptível à inativação em pH ácido do que alcalino, podendo também ser inativada pelo tratamento de calor.

  14. Thiol peroxidase-like activity of some intramolecularly coordinated ...

    Indian Academy of Sciences (India)

    Unknown

    the cell from oxidative stress.1 The enzyme (Enz-. SeH) reduces the peroxides to the corresponding al- cohol or water and in the process gets converted to .... Gas evolution was ..... Bromine/lithium exchange with n-BuLi in Et2O pro-.

  15. Study of antioxidant enzymes superoxide dismutase and glutathione peroxidase levels in tobacco chewers and smokers: A pilot study

    Directory of Open Access Journals (Sweden)

    Chundru Venkata Naga Sirisha

    2013-01-01

    Conclusions: The present study gave us an insight about the relationship between antioxidant enzyme activity, oxidative stress and tobacco. The altered antioxidant enzyme levels observed in this study will act as a predictor for pre potentially malignant lesions. Therefore an early intervention of tobacco habit and its related oxidative stress would prevent the development of tobacco induced lesions.

  16. Peroxidase-Mimicking Nanozyme with Enhanced Activity and High Stability Based on Metal-Support Interactions.

    Science.gov (United States)

    Li, Zhihao; Yang, Xiangdong; Yang, Yanbing; Tan, Yaning; He, Yue; Liu, Meng; Liu, Xinwen; Yuan, Quan

    2018-01-09

    Peroxidase-mimicking nanozymes offer unique advantages in terms of high stability and low cost over natural peroxidase for applications in bioanalysis, biomedicine, and the treatment of pollution. However, the design of high-efficiency peroxidase-mimicking nanozymes remains a great challenge. In this study, we adopted a structural-design approach through hybridization of cube-CeO 2 and Pt nanoparticles to create a new peroxidase-mimicking nanozyme with high efficiency and excellent stability. Relative to pure cube-CeO 2 and Pt nanoparticles, the as-hybridized Pt/cube-CeO 2 nanocomposites display much improved activities because of the strong metal-support interaction. Meanwhile, the nanocomposites also maintain high catalytic activity after long-term storage and multiple recycling. Based on their excellent properties, Pt/cube-CeO 2 nanocomposites were used to construct high-performance colorimetric biosensors for the sensitive detection of metabolites, including H 2 O 2 and glucose. Our findings highlight opportunities for the development of high-efficiency peroxidase-mimicking nanozymes with potential applications such as diagnostics, biomedicine, and the treatment of pollution. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. A peroxidase mimic with atom transfer radical polymerization activity constructed through the grafting of heme onto metal-organic frameworks.

    Science.gov (United States)

    Jiang, Wei; Pan, Yue; Yang, Jiebing; Liu, Yong; Yang, Yan; Tang, Jun; Li, Quanshun

    2018-07-01

    Atom transfer radical polymerization (ATRP) has been considered to be an efficient strategy for constructing functional macromolecules owing to its simple operation and versatile monomers, and thus it is of great significance to develop ideal catalysts with higher activity and perfect reusability. We constructed a peroxidase mimic through the grafting of heme onto metal-organic frameworks UiO-66-NH 2 (ZrMOF), namely Heme-ZrMOF. After the systematic characterization of structure, the composite Heme-ZrMOF was demonstrated to possess high peroxidase activity using 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) and 3,3',5,5'-tetramethylbenzidine as substrates. The enzyme mimic was then used as catalysts in the ATRP reactions of different monomers, in which favorable monomer conversion (44.6-98.0%) and product molecular weight (8600-25,600 g/mol) could be obtained. Compared to free heme, Heme-ZrMOF could efficiently achieve the easy separation of heme from the catalytic system and facilitate the ATRP reaction in an aqueous environment to avoid the utilization of organic solvents. In conclusion, the enzyme mimic Heme-ZrMOF could be potentially used as an effective catalyst for preparing well-defined polymers with biomedical applications. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Acquisition of Heat Stable Enzymes from Thermophilic Microorganisms: Peroxidases, Ureases, and Glucose Oxidases.

    Science.gov (United States)

    1992-04-01

    heptahydrate, 1.50 g/L boric acid, 0.05 g/L copper sulfate pentahydrate . 0.20 g/L molybdic acid dihydrate sodium salt and 0.05 g/L cobalt chloride...vanadium, cobalt, magnesium, potassium, zinc, copper , manganese, sodium, chloride and various forms of nitrogen. In addition to pH and temperature...growth may not coincide with the optimal conditions for production of the desired enzyme. For isolate #135, the sulfate , magnesium, potassium and

  19. Effect of different nutrient supply and other growth factors on the activity of the oxidizing enzymes in plants

    Energy Technology Data Exchange (ETDEWEB)

    Amberger, A

    1960-01-01

    Among the plants studied were french beans and peas; the oxidizing enzymes examined were ascorbic acid oxidase, cytochrome oxidase, phenol oxidase, peroxidase and catalase. Increasing the K dosage reduced enzyme activity and raised dry matter contents until at a very high dosage this action was reversed. Both N and P increased enzyme activity and yields. With B high enzyme activity and low dry matter content were both associated with deficiency and toxicity levels. Increasing the Fe dosage led to a rise in both dry matter content and enzyme activity, whereas F depressed yields and raised enzyme activity. Lack of water increased respiration. Light inhibited all enzyme activity.

  20. Fungal Community and Ligninolytic Enzyme Activities in Quercus deserticola Trel. Litter from Forest Fragments with Increasing Levels of Disturbance

    Directory of Open Access Journals (Sweden)

    Jesús A. Rosales-Castillo

    2017-12-01

    Full Text Available Litter fungal communities and their ligninolytic enzyme activities (laccase, Mn-peroxidase, and lignin-peroxidase play a vital role in forest biogeochemical cycles by breaking down plant cell wall polymers, including recalcitrant lignin. However, litter fungal communities and ligninolytic enzyme activities have rarely been studied in Neotropical, non-coniferous forests. Here, we found no significant differences in litter ligninolytic enzyme activities from well preserved, moderately disturbed, and heavily disturbed Quercus deserticola Trel. forests in central Mexico. However, we did find seasonal effects on enzyme activities: during the dry season, we observed lower laccase, and increased Mn-peroxidase and lignin-peroxidase activities, and in the rainy season, Mn-peroxidase and lignin-peroxidase activities were lower, while laccase activity peaked. Fungal diversity (Shannon-Weaver and Simpson indices based on ITS-rDNA analyses decreased with increased disturbance, and principal component analysis showed that litter fungal communities are structured differently between forest types. White-rot Polyporales and Auriculariales only occurred in the well preserved forest, and a high number of Ascomycota were shared between forests. While the degree of forest disturbance significantly affected the litter fungal community structure, the ligninolytic enzyme activities remained unaffected, suggesting functional redundancy and a possible role of generalist Ascomycota taxa in litter delignification. Forest conservation and restoration strategies must account for leaf litter and its associated fungal community.

  1. Association between Polymorphisms in Glutathione Peroxidase and Selenoprotein P Genes, Glutathione Peroxidase Activity, HRT Use and Breast Cancer Risk

    DEFF Research Database (Denmark)

    Méplan, Catherine; Dragsted, Lars Ove; Ravn-Haren, Gitte

    2013-01-01

    Breast cancer (BC) is one of the most common cancers in women. Evidence suggests that genetic variation in antioxidant enzymes could influence BC risk, but to date the relationship between selenoproteins and BC risk remains unclear. In this report, a study population including 975 Danish cases...... and 975 controls matched for age and hormone replacement therapy (HRT) use was genotyped for five functional single nucleotide polymorphisms (SNPs) in SEPP1, GPX1, GPX4 and the antioxidant enzyme SOD2 genes. The influence of genetic polymorphisms on breast cancer risk was assessed using conditional...... logistic regression. Additionally pre-diagnosis erythrocyte GPx (eGPx) activity was measured in a sub-group of the population. A 60% reduction in risk of developing overall BC and ductal BC was observed in women who were homozygous Thr carriers for SEPP1 rs3877899. Additionally, Leu carriers for GPX1 Pro...

  2. Peroxidase activity of the rat blood at prolonged intake of 137Cs

    Directory of Open Access Journals (Sweden)

    Yu. P. Grynevych

    2013-03-01

    Full Text Available Investigated peroxidase activity of blood white nonlinear rats-males by daily oral administration of 15 kBq 137Cs by chemiluminescence. Discovered oscillatory nature of the changes chemiluminescent indicators peroxi-dase oxidation of blood, the maximum deviation of the control are registered during the 4th and 60th days, and the minimum at the 1st, 7th and 135th days. Recovering kinetic parameters CL does not occur within 135 days of ob-servation (the 90th day of the completion of the introduction of radioactive cesium.

  3. Ascorbate Peroxidase and Catalase Activities and Their Genetic Regulation in Plants Subjected to Drought and Salinity Stresses

    Directory of Open Access Journals (Sweden)

    Adriano Sofo

    2015-06-01

    Full Text Available Hydrogen peroxide (H2O2, an important relatively stable non-radical reactive oxygen species (ROS is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses. Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT, ascorbate peroxidases (APX, some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in drought- and salt-stressed plants.

  4. Wound-induced expression of horseradish peroxidase.

    Science.gov (United States)

    Kawaoka, A; Kawamoto, T; Ohta, H; Sekine, M; Takano, M; Shinmyo, A

    1994-01-01

    Peroxidases have been implicated in the responses of plants to physiological stress and to pathogens. Wound-induced peroxidase of horseradish (Armoracia rusticana) was studied. Total peroxidase activity was increased by wounding in cell wall fractions extracted from roots, stems and leaves of horseradish. On the other hand, wounding decreased the peroxidase activity in the soluble fraction from roots. The enzyme activities of the basic isozymes were induced by wounding in horseradish leaves based on data obtained by fractionation of crude enzyme in isoelectric focusing gel electrophoresis followed by activity staining. We have previously isolated genomic clones for four peroxidase genes, namely, prxC1a, prxC1b, prxC2 and prxC3. Northern blot analysis using gene-specific probes showed that mRNA of prxC2, which encodes a basic isozyme, accumulated by wounding, while the mRNAs for other peroxidase genes were not induced. Tobacco (Nicotiana tabacum) plants were transformed with four chimeric gene constructs, each consisting of a promoter from one of the peroxidase genes and the β-glucuronidase (GUS) structural gene. High level GUS activity induced in response to wounding was observed in tobacco plants containing the prxC2-GUS construct.

  5. Effects of commercial selenium products on glutathione peroxidase activity and semen quality in stud boars

    Science.gov (United States)

    The aim of this study was to determine how dietary supplementation of inorganic and organic selenium affects selenium concentration and glutathione peroxidase activity in blood and sperm of sexually mature stud boars. Twenty-four boars of the Large White, Landrace, Pietrain, and Duroc breeds of opt...

  6. Aqueous synthesis of porous platinum nanotubes at room temperature and their intrinsic peroxidase-like activity.

    Science.gov (United States)

    Cai, Kai; Lv, Zhicheng; Chen, Kun; Huang, Liang; Wang, Jing; Shao, Feng; Wang, Yanjun; Han, Heyou

    2013-07-11

    Platinum nanotubes (PtNTs) exhibiting high porosity were constructed by sacrificing the exterior of tellurium nanowires (TeNWs) and disintegrating the inner part spontaneously in aqueous solution at room temperature, in which the Kirkendall effect may play an important role. The present PtNTs exhibited intrinsic peroxidase-like activity in the presence of H2O2.

  7. Clinical significance of quantitative analysis of thyroid peroxidase antibody (TPOAb) with chemiluminescence enzyme immunoassay

    International Nuclear Information System (INIS)

    Zhu Cuiying; Wang Qing; Huang Gang

    2004-01-01

    Objective: The only method of laboratory diagnosis for autoimmune thyroid diseases used to be serum TGA and TMA detections. Morerecently, quantitative analysis of TPOAb has been introduced. To assess the relative sensitivity of these tests , positive rates detected with the respective tests were compared. Methods: Serum TGA, TMA (with RIA) and TPOAb (with chemiluminescence enzyme immunoassay) were simultaneously detected in 998 cases of thyroid diseases (hyperthyroidism 307, Hashimoto's disease 193, simple goiter 498). For complementary sake, fine needle aspiration cytology was obtained in a number of cases including all the patients with Hashimoto's disease. Results: Positive detection rate of TPOAb in three groups of patients (hyperthyroidism, Hashimoto's, simple goiter) was 81.76%, 96.89 % and 42.97% respectively. With TMA, the positive rate was only 54.72%, 65.80%, 22.09% respectively. About one third more cases would be detected with the newer method. Conclusion: For the laboratory detection of auto immune thyroid diseases, quantitative analysis of TPOAb is much wore sensitive than the conventional TMA detection. (authors)

  8. Transmutation of human glutathione transferase A2-2 with peroxidase activity into an efficient steroid isomerase.

    Science.gov (United States)

    Pettersson, Par L; Johansson, Ann-Sofie; Mannervik, Bengt

    2002-08-16

    A major goal in protein engineering is the tailor-making of enzymes for specified chemical reactions. Successful attempts have frequently been based on directed molecular evolution involving libraries of random mutants in which variants with desired properties were identified. For the engineering of enzymes with novel functions, it would be of great value if the necessary changes of the active site could be predicted and implemented. Such attempts based on the comparison of similar structures with different substrate selectivities have previously met with limited success. However, the present work shows that the knowledge-based redesign restricted to substrate-binding residues in human glutathione transferase A2-2 can introduce high steroid double-bond isomerase activity into the enzyme originally characterized by glutathione peroxidase activity. Both the catalytic center activity (k(cat)) and catalytic efficiency (k(cat)/K(m)) match the values of the naturally evolved glutathione transferase A3-3, the most active steroid isomerase known in human tissues. The substrate selectivity of the mutated glutathione transferase was changed 7000-fold by five point mutations. This example demonstrates the functional plasticity of the glutathione transferase scaffold as well as the potential of rational active-site directed mutagenesis as a complement to DNA shuffling and other stochastic methods for the redesign of proteins with novel functions.

  9. Three-Dimensional Graphene Supported Bimetallic Nanocomposites with DNA Regulated-Flexibly Switchable Peroxidase-Like Activity.

    Science.gov (United States)

    Yuan, Fang; Zhao, Huimin; Zang, Hongmei; Ye, Fei; Quan, Xie

    2016-04-20

    A synergistic bimetallic enzyme mimetic catalyst, three-dimensional (3D) graphene/Fe3O4-AuNPs, was successfully fabricated which exhibited flexibly switchable peroxidase-like activity. Compared to the traditional 2D graphene-based monometallic composite, the introduced 3D structure, which was induced by the addition of glutamic acid, and bimetallic anchoring approach dramatically improved the catalytic activity, as well as the catalysis velocity and its affinity for substrate. Herein, Fe3O4NPs acted as supporters for AuNPs, which contributed to enhance the efficiency of electron transfer. On the basis of the measurement of Mott-Schottky plots of graphene and metal anchored hybrids, the catalysis mechanism was elucidated by the decrease of Fermi level resulted from the chemical doping behavior. Notably, the catalytic activity was able to be regulated by the adsorption and desorption of single-stranded DNA molecules, which laid a basis for its utilization in the construction of single-stranded DNA-based colorimetric biosensors. This strategy not only simplified the operation process including labeling, modification, and imprinting, but also protected the intrinsic affinity between the target and biological probe. Accordingly, based on the peroxidase-like activity and its controllability, our prepared nanohybrids was successfully adopted in the visualized and label-free sensing detections of glucose, sequence-specific DNA, mismatched nucleotides, and oxytetracycline.

  10. Cysteine peroxidase activity in rat blood plasma | Razygraev ...

    African Journals Online (AJOL)

    The rat plasma found to be able to accelerate greatly the H2O2-dependent oxidation of cysteine. The activity was a characteristic of a protein fraction precipitated at 30—44% ammonium sulfate saturation, and the specific activity in protein fraction was significantly higher than in plasma. Cysteine:H2O2 oxidoreductase ...

  11. Conformation and activity alteration of horseradish peroxidase induced by the interaction with gene carrier polyethyleneimines

    Science.gov (United States)

    Huang, Aimin; Wei, Bangzhi; Mo, Junyong; Wang, Yajing; Ma, Lin

    2018-01-01

    Polyethyleneimine (PEI) has long been considered as "golden standard" for polymeric gene delivery carriers. However the molecular basis of the cytotoxicity of PEI is poorly understood. Little is known about the effects of PEI on the structure and functions of biomacromolecules. In this work, fluorescence, UV-vis absorption, circular dichroism spectroscopy were conducted to investigate the influence of PEI of average molecular weight 25, 10 and 1.8 kDa (denoted as PEI25k, PEI10k and PEI1.8k) on the conformation of horseradish peroxidase (HRP) and its catalytic efficiency. Zeta-potential measurement and isothermal titration calorimetry were used to reveal the mechanism of the interaction between PEIs and HRP. PEIs were found to bind onto the surface of HRP predominantly via hydrophobic interaction and hydrogen bond or van der Waals interaction. The complex formation between HRP and PEI induced a more compact conformation of the enzyme and an increased hydrophobicity of the microenvironment surrounding heme pocket. The conformational change of HRP had little impact on the affinity towards H2O2 and phenol. However, the increase in the non-planarity of porphyrin ring in the heme group led to an increase in the exposure degree of the active center and thus an enhancement of catalytic efficiency of HRP in the presence of high molecular weight PEIs (PEI25k and PEI10k). The polymer size played an important role in PEI-HRP interaction. PEI of low molecular weight (PEI1.8k) was less efficient to alter the conformation and catalytic activity of HRP in aqueous solutions.

  12. Influence of air pollution by compounds of fluorine, sulphur and nitrogen on changes of peroxidase and polyphenol oxidase activity in the leaves of trees and bushes

    Directory of Open Access Journals (Sweden)

    Y. Prysedskyj

    2017-08-01

    Full Text Available The productive activity of man results in contamination of the environment which causes substantial damage to ecosystems, upsetting their balance, species composition, etc. Within industrial areas, plants suffer significant harm. At the same time, plant organisms play an important role in optimization of the environment, performing sanitary-hygienic, landscaping and aesthetic functions. In this context, we investigated the influence of industrial contamination of air by fluorine, sulphur and nitrogen compounds on the activity of peroxidase and polyphenoloxidase in ten types of arboreal and shrub plants which differ in their resistance to air pollution. Our research was conducted on the basis of a full multivariate experiment with two levels of factors. Peroxidase activity was determined by a colorimetric method according to the duration of oxidization of benzidine. For determination of polyphenoloxidase activity we determined the duration of oxidization of p-phenilendiamin according to the change in optical density of the solution. Pollutants have a significant influence on activity of the investigated enzymes in the leaves of the plant species studied, which depends on the resistance of the plants to contamination, and also the composition and concentrations of pollutants. With resistant species (Ligustrum vulgare L., Quercus robur L., Lonicera tatarica L., Eleagnus angustifolia L., Philadelphus coronaria L. peroxidase activity either did not change or rose by 11.2–64.1% compared to the control, depending on the composition of pollutants, their concentrations and the duration of their activity. Polyphenoloxidase activity in these plants did not significantly change in most variants of the experiment, although high concentrations of pollutants resulted in suppression of the activity of this enzyme by 26.1–37.6%. In species with variable tolerance which did not experience damage, peroxidase function did not change. Species sensitive to

  13. Peroxidase-like catalytic activities of ionic metalloporphyrins ...

    Indian Academy of Sciences (India)

    Unknown

    the various PS-MTPPS was seen to be Co>Mn>Fe, with CoTPPS showing efficiency ... obtained, by simple ion exchange method in aqueous conditions to get ... The relative activities of the PS-MTPPS resins were then evaluated by comparing.

  14. Mesoporous silica-encapsulated gold nanoparticles as artificial enzymes for self-activated cascade catalysis.

    Science.gov (United States)

    Lin, Youhui; Li, Zhenhua; Chen, Zhaowei; Ren, Jinsong; Qu, Xiaogang

    2013-04-01

    A significant challenge in chemistry is to create synthetic structures that mimic the complexity and function of natural systems. Here, a self-activated, enzyme-mimetic catalytic cascade has been realized by utilizing expanded mesoporous silica-encapsulated gold nanoparticles (EMSN-AuNPs) as both glucose oxidase- and peroxidase-like artificial enzymes. Specifically, EMSN helps the formation of a high degree of very small and well-dispersed AuNPs, which exhibit an extraordinarily stability and dual enzyme-like activities. Inspired by these unique and attractive properties, we further piece them together into a self-organized artificial cascade reaction, which is usually completed by the oxidase-peroxidase coupled enzyme system. Our finding may pave the way to use matrix as the structural component for the design and development of biomimetic catalysts and to apply enzyme mimics for realizing higher functions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Activation of glutathione peroxidase via Nrf1 mediates genistein's protection against oxidative endothelial cell injury

    International Nuclear Information System (INIS)

    Hernandez-Montes, Eva; Pollard, Susan E.; Vauzour, David; Jofre-Montseny, Laia; Rota, Cristina; Rimbach, Gerald; Weinberg, Peter D.; Spencer, Jeremy P.E.

    2006-01-01

    Cellular actions of isoflavones may mediate the beneficial health effects associated with high soy consumption. We have investigated protection by genistein and daidzein against oxidative stress-induced endothelial injury. Genistein but not daidzein protected endothelial cells from damage induced by oxidative stress. This protection was accompanied by decreases in intracellular glutathione levels that could be explained by the generation of glutathionyl conjugates of the oxidised genistein metabolite, 5,7,3',4'-tetrahydroxyisoflavone. Both isoflavones evoked increased protein expression of γ-glutamylcysteine synthetase-heavy subunit (γ-GCS-HS) and increased cytosolic accumulation and nuclear translocation of Nrf2. However, only genistein led to increases in the cytosolic accumulation and nuclear translocation of Nrf1 and the increased expression of and activity of glutathione peroxidase. These results suggest that genistein-induced protective effects depend primarily on the activation of glutathione peroxidase mediated by Nrf1 activation, and not on Nrf2 activation or increases in glutathione synthesis

  16. Effect of heat treatment on polyphenol oxidase and peroxidase ...

    African Journals Online (AJOL)

    GREGO

    2006-12-18

    Dec 18, 2006 ... enzymes in plant and its resistance to heat has been reported by a ... sintered glass funnel and washed with cold acetone under low vacuum ... Peroxidase activity was determined by measuring the colour deve- lopment at ...

  17. The effects of the sulfonylurea glyburide on glutathione peroxidase, superoxide dismutase and catalase activities in the heart tissue of streptozotocin-induced diabetic rat.

    Science.gov (United States)

    Bukan, N; Sancak, B; Bilgihan, A; Kosova, F; Buğdayci, G; Altan, N

    2004-09-01

    Oxygen free radicals have been suggested to be a contributory factor in diabetes complications. The aim of this study was to examine the effects of glyburide on the antioxidant enzyme activities in the heart tissue of diabetic rats. We investigated the activities of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) in the hearts of both control and streptozotocin-induced diabetic rats. In the heart of diabetic rats, the activity of total superoxide dismutase decreased significantly (p < 0.005), whereas the activity of catalase and glutathione peroxidase increased to a large extent (p < 0.0001 and p = 0.05, respectively) at the end of the fourth week compared with the control group. Glyburide treatment of diabetic rats for 4 weeks corrected the changes observed in diabetic heart. In addition, blood glucose levels of untreated diabetic rats decreased following the glyburide treatment. These results demonstrate that the sulfonylurea glyburide is capable of exerting direct insulin-like effect on heart superoxide dismutase, catalase and glutathione peroxidase activities of diabetic rats in vivo.

  18. Measuring the Enzyme Activity of Arabidopsis Deubiquitylating Enzymes.

    Science.gov (United States)

    Kalinowska, Kamila; Nagel, Marie-Kristin; Isono, Erika

    2016-01-01

    Deubiquitylating enzymes, or DUBs, are important regulators of ubiquitin homeostasis and substrate stability, though the molecular mechanisms of most of the DUBs in plants are not yet understood. As different ubiquitin chain types are implicated in different biological pathways, it is important to analyze the enzyme characteristic for studying a DUB. Quantitative analysis of DUB activity is also important to determine enzyme kinetics and the influence of DUB binding proteins on the enzyme activity. Here, we show methods to analyze DUB activity using immunodetection, Coomassie Brilliant Blue staining, and fluorescence measurement that can be useful for understanding the basic characteristic of DUBs.

  19. Photosynthetic pigments and peroxidase activity of Lepidium sativum L. during assisted Hg phytoextraction.

    Science.gov (United States)

    Smolinska, Beata; Leszczynska, Joanna

    2017-05-01

    The study was conducted to evaluate metabolic answer of Lepidium sativum L. on Hg, compost, and citric acid during assisted phytoextraction. The chlorophyll a and b contents, total carotenoids, and activity of peroxidase were determined in plants exposed to Hg and soil amendments. Hg accumulation in plant shoots was also investigated. The pot experiments were provided in soil artificially contaminated by Hg and/or supplemented with compost and citric acid. Hg concentration in plant shoots and soil substrates was determined by cold vapor atomic absorption spectroscopy (CV-AAS) method after acid mineralization. The plant photosynthetic pigments and peroxidase activity were measured by standard spectrophotometric methods. The study shows that L. sativum L. accumulated Hg in its aerial tissues. An increase in Hg accumulation was noticed when soil was supplemented with compost and citric acid. Increasing Hg concentration in plant shoots was correlated with enhanced activation of peroxidase activity and changes in total carotenoid concentration. Combined use of compost and citric acid also decreased the chlorophyll a and b contents in plant leaves. Presented study reveals that L. sativum L. is capable of tolerating Hg and its use during phytoextraction assisted by combined use of compost and citric acid lead to decreasing soil contamination by Hg.

  20. Effect of cadmium on growth, protein content and peroxidase activity in pea plants

    International Nuclear Information System (INIS)

    Bavi, K.; Kholdebarin, B.

    2011-01-01

    n this study the effects of different cadmium chloride concentrations (5, 10, 20, 50, and 100 mu M) on some physiological and biochemical processes including seed germination, root and shoot fresh and dry weight, protein content and peroxidase activity in peas (Cicer arietinum cv. pars) were investigated. Cadmium did not have any significant effect on the rate of pea seed germination. However, it affected the subsequent growth rate in these plants. Higher cadmium concentrations specially at 50 and 100 mu M reduced plant growth significantly. Leaf chlorosis, wilting and leaf abscission were observed in plants treated with cadmium. Protein content in pea roots reduced significantly in the presence of high cadmium concentrations. Low concentrations of CdCl/sub 2/ resulted in higher peroxidase activity both in roots and shoots of pea plants. (author)

  1. Caracterização isozimática e atividade de peroxidase em folhas de plantas hiperídrica, intermediária e normal de Bidens pilosa L. mantidas in vitro Isoezymatic characterization and peroxidase activity in leaves of hyperhydric, intermediary and normal plants of Bidens pilosa L. grown in vitro

    Directory of Open Access Journals (Sweden)

    José Emílio Zanzirolani de Oliveira

    2008-02-01

    Full Text Available Foram caracterizadas as plantas: hiperídrica, intermediária e normal de um clone de Bidens pilosa mantido em cultivo in vitro por meio de isozimas e da atividade de peroxidase. Empregando-se a eletroforese em géis de amido a 12%, testou-se seis isozimas, sendo detectado polimorfismo em peroxidase e fosfatase ácida, permitindo caracterizar cada tipo de planta. Não houve polimorfismo em fosfogluco isomerase, fosfoglucomutase, glutamato oxaloacetato transaminase e malato desidrogenase. A atividade da peroxidase foi maior nas plantas hiperídricas e intermediárias. Conclui-se que a variabilidade enzimática tem potencial como marcador de hiperidricidade em plantas mantidas in vitro.Activity of peroxidase (EC 1.11.1.7 and isozymes analysis of a Bidens pilosa clone maintained in vitro culture were characterized in hyperhydric, intermediary and normal plants. Electrophorese in starch gels (12% of six isozymes systems was tested, polymorphisms in peroxidase and acid phosphatase (EC 3.1.3.2 were detected. There was absence of polymorphism in phosphoglucoisomerase (EC 5.3.1.9, phosphoglucomutase (EC 5.4.2.2, glutamate oxaloacetate transaminase (EC 2.6.1.1 and malate dehydrogenase (EC 1.1.1.37. Comparing the activity of peroxidase enzyme, it was higher in hyperhydric and intermediary plants in relation to normal ones. Enzymatic variability is a potential tool as hyperhydricity marker in plants grown in vitro.

  2. Fe(III)-TAML activator: a potent peroxidase mimic for chemiluminescent determination of hydrogen peroxide.

    Science.gov (United States)

    Vdovenko, Marina M; Demiyanova, Alexandra S; Kopylov, Kirill E; Sakharov, Ivan Yu

    2014-07-01

    Efforts to replace native peroxidase with its low molecular weight alternatives have stimulated a search for peroxidase mimetics. Herein we describe the oxidation of luminol with hydrogen peroxide catalyzed by commercially available Fe(III)-TAML activator 1a, which was shown to be a more active catalyst than hemin. At Fe(III)-TAML activator 1a use in chemiluminescent assay for H2O2 determination the detection limit value (3σ) of 5×10(-8)M was similar to the detection limit obtained with horseradish peroxidase (1×10(-7)M) and significantly lower than that obtained in the presence of hemin (6×10(-7)M). The linear ranges (R(2)=0.98) of the assay were 6×10(-8)-1×10(-6)M and 6×10(-7)-1×10(-6)M H2O2 for Fe(III)-TAML 1a and hemin, respectively. The CV values for Fe(III)-TAML 1a-based assay measured within the working range varied from 1.0% to 3.7% (n=4), whereas in the case of hemin -5.0% to 9.7% (n=4). Moreover, the sensitivity of Fe(III)-TAML 1a-based method was 56 and 5 times higher than that of hemin- and HRP-based methods, respectively. The obtained results open good perspectives to apply Fe(III)-TAML activator 1a in CL analytical methods instead of hemin, a traditionally used peroxidase mimetic. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. V2O5 nanowires with an intrinsic peroxidase-like activity

    NARCIS (Netherlands)

    André, R.; Natálio, F.; Humanes, M.; Leppin, J.; Heinze, K.; Wever, R.; Schröder, H.C.; Müller, W.E.G.; Tremel, W.

    2011-01-01

    V2O5 nanowires exhibit an intrinsic catalytic activity towards classical peroxidase substrates such as 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 3,3,5,5,-tetramethylbenzdine (TMB) in the presence of H2O2. These V2O5 nanowires show an optimum reactivity at a pH of 4.0 and the

  4. Unprecedented access of phenolic substrates to the heme active site of a catalase: substrate binding and peroxidase-like reactivity of Bacillus pumilus catalase monitored by X-ray crystallography and EPR spectroscopy.

    Science.gov (United States)

    Loewen, Peter C; Villanueva, Jacylyn; Switala, Jacek; Donald, Lynda J; Ivancich, Anabella

    2015-05-01

    Heme-containing catalases and catalase-peroxidases catalyze the dismutation of hydrogen peroxide as their predominant catalytic activity, but in addition, individual enzymes support low levels of peroxidase and oxidase activities, produce superoxide, and activate isoniazid as an antitubercular drug. The recent report of a heme enzyme with catalase, peroxidase and penicillin oxidase activities in Bacillus pumilus and its categorization as an unusual catalase-peroxidase led us to investigate the enzyme for comparison with other catalase-peroxidases, catalases, and peroxidases. Characterization revealed a typical homotetrameric catalase with one pentacoordinated heme b per subunit (Tyr340 being the axial ligand), albeit in two orientations, and a very fast catalatic turnover rate (kcat  = 339,000 s(-1) ). In addition, the enzyme supported a much slower (kcat  = 20 s(-1) ) peroxidatic activity utilizing substrates as diverse as ABTS and polyphenols, but no oxidase activity. Two binding sites, one in the main access channel and the other on the protein surface, accommodating pyrogallol, catechol, resorcinol, guaiacol, hydroquinone, and 2-chlorophenol were identified in crystal structures at 1.65-1.95 Å. A third site, in the heme distal side, accommodating only pyrogallol and catechol, interacting with the heme iron and the catalytic His and Arg residues, was also identified. This site was confirmed in solution by EPR spectroscopy characterization, which also showed that the phenolic oxygen was not directly coordinated to the heme iron (no low-spin conversion of the Fe(III) high-spin EPR signal upon substrate binding). This is the first demonstration of phenolic substrates directly accessing the heme distal side of a catalase. © 2015 Wiley Periodicals, Inc.

  5. Epigenetics of dominance for enzyme activity

    Indian Academy of Sciences (India)

    Unknown

    dimer over a wide range of H+ concentrations accounts for the epigenetics of dominance for enzyme activity. [Trehan K S ... The present study has been carried on acid phosphatase .... enzyme activity over mid parent value (table 3, col. 13),.

  6. Guaiacol Peroxidase Zymography for the Undergraduate Laboratory

    Science.gov (United States)

    Wilkesman, Jeff; Castro, Diana; Contreras, Lellys M.; Kurz, Liliana

    2014-01-01

    This laboratory exercise presents a novel way to introduce undergraduate students to the specific detection of enzymatic activity by electrophoresis. First, students prepare a crude peroxidase extract and then analyze the homogenate via electrophoresis. Zymography, that is, a SDS-PAGE method to detect enzyme activity, is used to specifically…

  7. Effect of biological and chemical preparations on peroxidase activity in leaves of tomato plants

    Directory of Open Access Journals (Sweden)

    Yulia Kolomiets

    2016-10-01

    Full Text Available In terms of treating tomato variety Chaika with chemical preparations with active substances if aluminum phosphate, 570 g/l + phosphorous acid 80 g/,l and mankotseb in concentration of 640 g/kg, the maximum increase in peroxidase activity in leaves of plants was observed in12 hours. In terms of use of biological preparations based on living cells Bacillus subtilis and Azotobacter chroococcum its activity was maximum in 24 hours and ranged from 77.7 to 112.7 un.mg-1•s-1

  8. Activity and isoenzyme spectrum of peroxidases and dehydrins of some plant species, growing on the shores of lake Baikal, under abiotic stress

    Directory of Open Access Journals (Sweden)

    M.A. Zhivet’ev

    2010-11-01

    Full Text Available Termostability and optimal pH of weak-associated with plant cell wall and soluble peroxidases was shown to change in relation to natural conditions and season of year. Also the activity of peroxidase was variable during vegetation period. Dehydrine expression was followed by spike of peroxidase activity (and, a priori, an increase of hydrogen peroxide concentration.

  9. A Novel Colorimetric Immunoassay Utilizing the Peroxidase Mimicking Activity of Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hyun Gyu Park

    2013-05-01

    Full Text Available A simple colorimetric immunoassay system, based on the peroxidase mimicking activity of Fe3O4 magnetic nanoparticles (MNPs, has been developed to detect clinically important antigenic molecules. MNPs with ca. 10 nm in diameter were synthesized and conjugated with specific antibodies against target molecules, such as rotaviruses and breast cancer cells. Conjugation of the MNPs with antibodies (MNP-Abs enabled specific recognition of the corresponding target antigenic molecules through the generation of color signals arising from the colorimetric reaction between the selected peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB and H2O2. Based on the MNP-promoted colorimetric reaction, the target molecules were detected and quantified by measuring absorbance intensities corresponding to the oxidized form of TMB. Owing to the higher stabilities and economic feasibilities of MNPs as compared to horseradish peroxidase (HRP, the new colorimetric system employing MNP-Abs has the potential of serving as a potent immunoassay that should substitute for conventional HRP-based immunoassays. The strategy employed to develop the new methodology has the potential of being extended to the construction of simple diagnostic systems for a variety of biomolecules related to human cancers and infectious diseases, particularly in the realm of point-of-care applications.

  10. Green tea and its major polyphenol EGCG increase the activity of oral peroxidases.

    Science.gov (United States)

    Narotzki, Baruch; Levy, Yishai; Aizenbud, Dror; Reznick, Abraham Z

    2013-01-01

    Oral peroxidases (OPO) consist mainly of salivary peroxidase and myeloperoxidase and are involved in oral defense mechanisms. Salivary peroxidase is synthesized and secreted by salivary glands, whereas myeloperoxidase is found in polymorphonuclear leukocytes, which migrate into the oral cavity at gingival crevices. Green tea is the world's second most popular drink after water. Polyphenols are the most biologically active group of tea components. The purpose of our study was to elucidate the interaction between green tea & EGCG (Epigallocatechin 3-gallate), its main polyphenol and OPO. In previous studies we have shown that elderly trained people who drink green tea for 3 months, have a higher level of OPO activity compared to non-drinkers. Thus, we decided to extend our project in order to understand the above observations by studying the interaction of green tea and OPO both in vitro and in vivo. Addition of green tea and black tea infusions (50 μl/ml) and EGCG (50 μM) to saliva, resulted in a sharp rise of OPO activity +280% (p = 0.009), 54% (p = 0.04) and 42% (p = 0.009), respectively. The elevation of OPO activity due to addition of green tea and EGCG was in a dose dependent manner: r = 0.91 (p = 0.001) and r = 0.637 (p = 0.019), respectively. Also, following green tea infusion mouth rinsing, a rise of OPO activity was observed: +268% (p = 0.159). These results may be of great clinical importance, as tea consumer's oral epithelium may have better protection against the deleterious effects of hydroxyl radicals, produced by not removed hydrogen peroxides in the presence of metal ions. Higher OPO activity upon green tea drinking may provide an extra protection against oxidative stress in the oral cavity.

  11. Preparation and characterization of a carbon-based magnetic nanostructure via co-precipitation method: Peroxidase-like activity assay with 3,3ʹ,5,5ʹ-tetramethylbenzidine

    Directory of Open Access Journals (Sweden)

    Navvabeh Salarizadeh

    2017-09-01

    Full Text Available Objective(S: Natural and artificial enzymes have shown important roles in biotechnological processes. Recently, design and synthesis of artificial enzymes especially peroxidase mimics has been interested by many researchers. Due to disadvantages of natural peroxidases, there is a desirable reason of current research interest in artificial peroxidase mimics. Methods: In this study, magnetic multiwall carbon nanotubes with a structure of Fe3O4/MWCNTs as enzyme mimetic were fabricated using in situ co-precipitation method. The structure, composition, and morphology of Fe3O4/MWCNTs nanocomposite were characterized using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, and transmission electron microscopy (TEM. The magnetic properties were investigated by the vibrating sample magnetometer (VSM. Peroxidase-like catalytic activity of nanocomposite was investigated using colorimetric and electrochemical tests with 3,3ʹ,5,5ʹ-tetramethylbenzidine (TMB substrate. Results: The obtained data proved the synthesis of Fe3O4/MWCNTs nanocomposite. The average crystallite size of nanostructures was estimated about 12 nm by Debye–Scherer equation. It was found that Fe3O4/MWCNTs nanocomposite exhibit peroxidase-like activity. Colorimetric and electrochemical data demonstrated that prepared nanocomplex has higher catalytic activity toward H2O2 than pure MWCNT nanocatalyst. From electrochemical tests concluded that the Fe3O4/MWCNTs electrode exhibited the better redox response to H2O2, which is ~ 2 times larger than that of the MWCNTs. Conclusions: The synthesis of Fe3O4nanoparticles on MWCNTs was successfully performed by in situ co-precipitation process. Fe3O4/MWCNTs nanocatalyst exhibited a good peroxidase-like activity. These biomimetic catalysts have some advantages such as simplicity, stability and cost effectiveness that can be used in the design of enzyme-based devices for various applied fields.

  12. Interrogating the activities of conformational deformed enzyme by single-molecule fluorescence-magnetic tweezers microscopy

    Science.gov (United States)

    Guo, Qing; He, Yufan; Lu, H. Peter

    2015-01-01

    Characterizing the impact of fluctuating enzyme conformation on enzymatic activity is critical in understanding the structure–function relationship and enzymatic reaction dynamics. Different from studying enzyme conformations under a denaturing condition, it is highly informative to manipulate the conformation of an enzyme under an enzymatic reaction condition while monitoring the real-time enzymatic activity changes simultaneously. By perturbing conformation of horseradish peroxidase (HRP) molecules using our home-developed single-molecule total internal reflection magnetic tweezers, we successfully manipulated the enzymatic conformation and probed the enzymatic activity changes of HRP in a catalyzed H2O2–amplex red reaction. We also observed a significant tolerance of the enzyme activity to the enzyme conformational perturbation. Our results provide a further understanding of the relation between enzyme behavior and enzymatic conformational fluctuation, enzyme–substrate interactions, enzyme–substrate active complex formation, and protein folding–binding interactions. PMID:26512103

  13. Changes in Peroxidase Activity in the Peel of Unshiub Mandarin (Citrus unshiu Marc. Fruit with Different Storage Treatments

    Directory of Open Access Journals (Sweden)

    Hrvoje Lepeduš

    2005-01-01

    Full Text Available The Unshiu mandarin (Citrus unshiu Marc. is the major Citrus crop in Croatia. Limiting factors for longer consumption of Unshiu mandarin are low storage performance and the appearance of chilling injuries during storage. Previous studies indicated that oxidative stress might be involved in cold-induced peel damage of harvested Citrus fruit. The aim of the present study was to investigate peroxidase distribution, isoenzyme pattern and activity in the peel of Unshiu mandarin fruit. Special goal of our study was to investigate the changes of peroxidase activity in respect to two different hot water dipping (HWD treatments (3 min at 48 and 52 °C and two different storage temperatures (1 and 3 °C combined. Peroxidase activity was detected at the border of oil glands, in the peel surface and in the conducting elements positioned in the inner part of the peel. Electrophoretic analysis revealed the presence of two peroxidase isoenzymes. There were no differences in the electrophoretic pattern after the HWD treatments and cold storage. Lowering of both total and specific peroxidase activity was measured in HWD-treated samples in comparison with the control ones. However, it appeared that significant decrease in total peroxidase activity was influenced by the storage temperatures, while the increase in total soluble protein content was influenced by the HWD pretreatment.

  14. Effects of acetylcysteine and probucol on contrast medium-induced depression of intrinsic renal glutathione peroxidase activity in diabetic rats.

    Science.gov (United States)

    Yen, Hsueh-Wei; Lee, Hsiang-Chun; Lai, Wen-Te; Sheu, Sheng-Hsiung

    2007-04-01

    Antioxidants such as N-acetylcysteine and probucol have been used to protect patients from contrast media-induced nephrotoxicity. The mechanisms underlying these protective effects are not well understood. We hypothesized that acetylcysteine and probucol alter the activity of endogenous antioxidant enzyme activity. Four weeks after induction of diabetes with streptozotocin, diabetic and nondiabetic rats were divided into three groups. Group 1 rats did not receive any antioxidant agents. Group 2 rats were treated with acetylcysteine and group 3 rats with probucol for 1 week before injection of the contrast medium diatrizoate (DTZ). We found that diabetic rats had higher renal glutathione peroxidase (GPx) activity than normal rats. DTZ suppressed renal GPx activity significantly in both group 1 diabetic and normal rats. Interestingly, renal GPx activity in both diabetic and normal rats pretreated with acetylcysteine or probucol was not inhibited by DTZ. Renal superoxide dismutase (SOD) increased significantly in normal rats after DTZ injection, but not in diabetic rats. Finally, acetylcysteine or probucol did not significantly influence renal SOD. These findings suggest that the renal protective effects of acetylcysteine and probucol against contrast-induced oxidative stress and nephrotoxicity may be mediated by altering endogenous GPx activity.

  15. Leishmania mexicana amazonensis: heterogeneity in 5-nucleotidase and peroxidase activities of mononuclear phagocytes during in vivo and in vitro infection Leishmania mexicana amazonensis: heterogeneidade da 5’-Nucleotidase e da peroxidase em fagócitos mononucleares durante infecção in vivo e in vitro

    OpenAIRE

    Suzana Côrte-Real; Gabriel Grimaldi Junior; Maria de Nazareth Leal de Meirelles

    1988-01-01

    The degree of maturation of cells of the Mononuclear Phagocyte System (MPS), during in vivo and in vitro infection by Leishmania mexicana amazonenesis, was evaluated in this study. The macrophages' differentiation was assayed by cytochemical characterization at the ultrastrctural level, using two well-established markers: 5'-nucleotidase enzyme activity, for revealing the mature cells, and the peroxidase activity present in the cell granules to demonstrate immature mononuclear phagocytes. onl...

  16. Inhibition mechanism of lanthanum ion on the activity of horseradish peroxidase in vitro

    Science.gov (United States)

    Guo, Shaofen; Wang, Lihong; Lu, Aihua; Lu, Tianhong; Ding, Xiaolan; Huang, Xiaohua

    2010-02-01

    In order to understand the inhibition mechanism of lanthanum ion (La 3+) on the activity of horseradish peroxidase (HRP), the effects of La 3+ on the activity, electron transfer and conformation of HRP in vitro were investigated by using cyclic voltammetry (CV), atomic force microscopy (AFM), circular dichroism (CD), high performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF/MS) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that La 3+ can combine with the amide groups of the polypeptide chain in HRP molecule, forming the complex of La 3+ and HRP (La-HRP). The formation of the La-HRP complex causes the destruction of the native structure of HRP molecule, leading to the decrease in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then in the exposure extent of active center, Fe(III) of the porphyrin ring of HRP molecule. Thus, the direct electrochemical and catalytic activities of HRP are decreased. It is a possible inhibition mechanism of La 3+ on the activity of peroxidase.

  17. Contemplation of wheat genotypes for enhanced antioxidant enzyme activity

    International Nuclear Information System (INIS)

    Nasim, S.; Shabbir, G.; Ilyas, M.

    2017-01-01

    Wheat (Triticum aestivum L.) is leading cereal crop in Pakistan but its yield is highly affected due to various abiotic factors especially drought stress, which affects the metabolism of plants. The present study was conducted at Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, using thirty three genotypes during 2011 to investigate the response of anti oxidative enzymes. Seedlings were subjected to stress condition with 30 % PEG 6000 solution along with control (irrigated with water) under in vitro conditions. The experiment was conducted in pots following Complete Randomized Design in Laboratory. Results revealed that under control conditions the maximum values for Guaiacol peroxidase were found in Punjab-96 and Auqab-2000 (2.523), for superoxide in C-273 (0.294), for ascorbate peroxide in PAK-81 (2.523) and for catalase in Kohsar-95 (0.487). Under moisture stress condition the maximum value for Guaiacol peroxidase were recorded for Kohsar-95 (2.699), for superoxide in Kohsar-95 (1.259), for ascorbate peroxide in Pak-81, SA-75, Mexipak-65 and PARI-73 (3.000) and for catalase in Mexipak-65 (0.640). The genotypes which showed higher antioxidant enzyme activity under drought stress have the ability to perform better under adverse soil moisture condition. Such potential genotypes can be utilized in the future breeding programs and also in improving the wheat varieties against drought stress. (author)

  18. Relationship between Estradiol and Antioxidant Enzymes Activity of Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Nasrin Sheikh

    2009-01-01

    Full Text Available Some evidence suggests the neuroprotection of estrogen provided by the antioxidant activity of this compound. The main objective of this study was to determine the level of estradiol and its correlation with the activity of antioxidant enzymes, total antioxidant status and ferritin from ischemic stroke subjects. The study population consisted of 30 patients with acute ischemic stroke and 30 controls. There was no significant difference between estradiol in stroke and control group. The activity of superoxide dismutase and level of ferritin was higher in stroke compared with control group (<.05, <.001, resp.. There was no significant correlation between estradiol and glutathione peroxidase, glutathione reductase, catalase, total antioxidant status, and ferritin in stroke and control groups. We observed inverse correlation between estradiol with superoxide dismutase in males of stroke patients (=−0.54, =.029. Our results supported that endogenous estradiol of elderly men and women of stroke or control group has no antioxidant activity.

  19. Luffa aegyptiaca (Gourd) Fruit Juice as a Source of Peroxidase.

    Science.gov (United States)

    Yadav, R S S; Yadav, K S; Yadav, H S

    2011-01-01

    Peroxidases have turned out to be potential biocatalyst for a variety of organic reactions. The research work reported in this communication was done with the objective of finding a convenient rich source of peroxidase which could be used as a biocatalyst for organic synthetic reactions. The studies made have shown that Luffa aegyptiaca (gourd) fruit juice contains peroxidase activity of the order of 180 enzyme unit/mL. The K(m) values of this peroxidase for the substrates guaiacol and hydrogen peroxide were 2.0 and 0.2 mM, respectively. The pH and temperature optima were 6.5 and 60°C, respectively. Like other peroxidases, it followed double displacement type mechanism. Sodium azide inhibited the enzyme competitively with K(i) value of 3.35 mM.

  20. Luffa aegyptiaca (Gourd Fruit Juice as a Source of Peroxidase

    Directory of Open Access Journals (Sweden)

    R. S. S. Yadav

    2011-01-01

    Full Text Available Peroxidases have turned out to be potential biocatalyst for a variety of organic reactions. The research work reported in this communication was done with the objective of finding a convenient rich source of peroxidase which could be used as a biocatalyst for organic synthetic reactions. The studies made have shown that Luffa aegyptiaca (gourd fruit juice contains peroxidase activity of the order of 180 enzyme unit/mL. The Km values of this peroxidase for the substrates guaiacol and hydrogen peroxide were 2.0 and 0.2 mM, respectively. The pH and temperature optima were 6.5 and 60°C, respectively. Like other peroxidases, it followed double displacement type mechanism. Sodium azide inhibited the enzyme competitively with Ki value of 3.35 mM.

  1. [Antimutagenic activity of plant extracts from Armoracia rusticana, Ficus carica and Zea mays and peroxidase in eukaryotic cells].

    Science.gov (United States)

    Agabeĭli, R A; Kasimova, T E; Alekperov, U K

    2004-01-01

    Antimutagene activity and high efficiency of antimutagene action of plant extracts from horseradish roots (Armoracia rusticana), fig brunches (Ficus carica) and mays seedlings (Zea mays) and their ability to decrease the frequency of spontaneous and induced by gamma-rays chromosome aberrations in meristematic cells of Vicia faba and marrow cells of mice have been shown. Comparative assessment of genoprotective properties of peroxidase and the studied extracts has revealed higher efficiency of antimutagene action of peroxidase.

  2. An oxidative burst and its attenuation by bacterial peroxidase activity is required for optimal establishment of the Arachis hypogaea-Bradyrhizobium sp. symbiosis.

    Science.gov (United States)

    Muñoz, V; Ibáñez, F; Figueredo, M S; Fabra, A

    2016-07-01

    The main purpose of this study was to determine whether the Arachis hypogaea L. root oxidative burst, produced at early stages of its symbiotic interaction with Bradyrhizobium sp. SEMIA 6144, and the bacterial antioxidant system are required for the successful development of this interaction. Pharmacological approaches were used to reduce both plant oxidative burst and bacterial peroxidase enzyme activity. In plants whose H2 O2 levels were decreased, a low nodule number, a reduction in the proportion of red nodules (%) and an increase in the bacteroid density were found. The symbiotic phenotype of plants inoculated with a Bradyrhizobium sp. SEMIA 6144 culture showing decreased peroxidase activity was also affected, since the biomass production, nodule number and percentage of red nodules in these plants were lower than in plants inoculated with Bradyrhizobium sp. control cultures. We demonstrated for the first time that the oxidative burst triggered at the early events of the symbiotic interaction in peanut, is a prerequisite for the efficient development of root nodules, and that the antioxidant system of bradyrhizobial peanut symbionts, particularly the activity of peroxidases, is counteracting this oxidative burst for the successful establishment of the symbiosis. Our results provide new insights into the mechanisms involved in the development of the symbiotic interaction established in A. hypogaea L. a legume infected in an intercellular way. © 2016 The Society for Applied Microbiology.

  3. Production and Purification of Peroxidase from Aspergillus niger.

    Directory of Open Access Journals (Sweden)

    Mohammed A. Jebor

    2017-02-01

    Full Text Available This study was conducted in the laboratories of Biology Department, College of Science, which deals with isolation and purification of peroxidase and optimization of process parameters to achieve maximum yield of peroxidase by Aspergillus niger. Solid-state fermentation of Aspergillus niger was carried out for enhanced production of peroxidase using hydrogen peroxide as the substrate of enzyme maximum activity of the enzyme was achieved under optimum growth conditions. The optimum conditions were the isolated of Aspergillus niger from soil and growth in synthetic medium, it gave high titer of peroxidase activity, the fructose as carbon source, peptone as nitrogen source, after 12 days of incubation, incubation temperature 25 °C and pH = 6.5. Peroxidase purified in four purification steps; precipitation with 70% saturation of ammonium sulfate, step of dialysis, the third by ion exchange chromatography using DEAE-Cellulose and fourth by gel filtration throughout Sephadex G-100. The specific activity of the purified enzyme was 150U/mg with 7.75 folds. The peroxidase was shown to have molecular weight of 40kDa in SDS-PAGA and about 40kDa in gel filtration.The optimum pH and temperature for peroxidase activity 7 and 35 C0 respectively.

  4. The effect of excimer laser keratectomy on corneal glutathione peroxidase activities and aqueous humor selenium levels in rabbits.

    Science.gov (United States)

    Yis, Ozgür; Bilgihan, Ayşe; Bilgihan, Kamil; Yis, Nilgün Safak; Hasanreisoğlu, Berati

    2002-06-01

    The formation of free oxygen radicals has been demonstrated in the corneal tissue after 193 nm laser irradiation. Cornea has several defense mechanisms that protect against oxidative damage. One of them, glutathione peroxidase (GPx), catalyzes the destruction of hydrogen peroxide and lipid hydroperoxide. Selenium is a trace element which is incorporated into the selenoenzyme GPx. In the present study, the effect of excimer laser keratectomy on corneal GPx activities and aqueous humor selenium concentrations in rabbits was evaluated. Animals were divided into five groups, and all groups were compared: controls (group 1), after epithelial scraping (group 2), transepithelial photorefractive keratectomy(PRK; group 3), superficial traditional PRK (50 microm; group 4) and deep traditional PRK (100 microm; group 5). Corneal GPx activities were measured by a modification of the coupled assay procedure. Aqueous humor selenium concentrations were determined using hydride generation atomic absorption spectrometry. Corneal GPx activities were significantly lower only in group 5 ( P<0.05), and the selenium concentration in the aqueous humor did not change in any group. Deep corneal photoablation inhibits GPx enzyme activities in the cornea. Therefore, antioxidants may be useful in reducing free radical-mediated complications after excimer laser corneal photoablation.

  5. Structure of Thermobifida fusca DyP-type peroxidase and activity towards Kraft lignin and lignin model compounds.

    Science.gov (United States)

    Rahmanpour, Rahman; Rea, Dean; Jamshidi, Shirin; Fülöp, Vilmos; Bugg, Timothy D H

    2016-03-15

    A Dyp-type peroxidase enzyme from thermophilic cellulose degrader Thermobifida fusca (TfuDyP) was investigated for catalytic ability towards lignin oxidation. TfuDyP was characterised kinetically against a range of phenolic substrates, and a compound I reaction intermediate was observed via pre-steady state kinetic analysis at λmax 404 nm. TfuDyP showed reactivity towards Kraft lignin, and was found to oxidise a β-aryl ether lignin model compound, forming an oxidised dimer. A crystal structure of TfuDyP was determined, to 1.8 Å resolution, which was found to contain a diatomic oxygen ligand bound to the heme centre, positioned close to active site residues Asp-203 and Arg-315. The structure contains two channels providing access to the heme cofactor for organic substrates and hydrogen peroxide. Site-directed mutant D203A showed no activity towards phenolic substrates, but reduced activity towards ABTS, while mutant R315Q showed no activity towards phenolic substrates, nor ABTS. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Activation of interfacial enzymes at membrane surfaces

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Andresen, Thomas Lars; Halperin, Avi

    2006-01-01

    A host of water-soluble enzymes are active at membrane surfaces and in association with membranes. Some of these enzymes are involved in signalling and in modification and remodelling of the membranes. A special class of enzymes, the phospholipases, and in particular secretory phospholipase A2 (s...

  7. Hemin-Graphene Derivatives with Increased Peroxidase Activities Restrain Protein Tyrosine Nitration.

    Science.gov (United States)

    Xu, Huan; Yang, Zhen; Li, Hailing; Gao, Zhonghong

    2017-12-14

    Protein tyrosine nitration is implicated in the occurrence and progression of pathological conditions involving free radical reactions. It is well recognized that hemin can catalyze protein tyrosine nitration in the presence of nitrite and hydrogen peroxide. Generally, the catalytic efficiency is positively correlated to its peroxidase activity. In this study, however, it is found that the efficiency of hemin in catalyzing protein tyrosine nitration is largely suppressed after functionalization with graphene derivatives, even though its peroxidase-like activity is more than quadrupled. Further studies show that the oxidation of tyrosine is still observed for these composites; dityrosine formation, however, is greatly inhibited. Furthermore, these composites also exhibit strong effects on the oxidation of nitrite into nitrate. Therefore, we propose a mechanism in which hemin-graphene derivatives facilitate the oxidation of tyrosine and nitrite to produce tyrosyl radicals and nitrogen dioxide radicals in the presence of hydrogen peroxide, but graphene interlayers serve as barriers that hinder radical-radical coupling reactions; consequently, protein tyrosine nitration is restrained. This property of hemin-graphene derivatives, by which they catalyze substrate oxidation but suppress radical-radical coupling reactions, shows their great potential in selective oxidation procedures for byproduct removal. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The study of ascorbate peroxidase, catalase and peroxidase during in vitro regeneration of Argyrolobium roseum.

    Science.gov (United States)

    Habib, Darima; Chaudhary, Muhammad Fayyaz; Zia, Muhammad

    2014-01-01

    Here, we demonstrate the micropropagation protocol of Argyrolobium roseum (Camb.), an endangered herb exhibiting anti-diabetic and immune-suppressant properties, and antioxidant enzymes pattern is evaluated. Maximum callogenic response (60 %) was observed from leaf explant at 1.0 mg L(-1) 1-nephthalene acetic acid (NAA) and 0.5 mg L(-1) 6-benzyl aminopurine (BA) in Murashige and Skoog (MS) medium using hypocotyl and root explants (48 % each). Addition of AgNO3 and PVP in the culture medium led to an increase in callogenic response up to 86 % from leaf explant and 72 % from hypocotyl and root explants. The best shooting response was observed in the presence of NAA, while maximum shoot length and number of shoots were achieved based on BA-supplemented MS medium. The regenerated shoots were rooted and successfully acclimatized under greenhouse conditions. Catalase and peroxidase enzymes showed ascending pattern during in vitro plant development from seed while ascorbate peroxidase showed descending pattern. Totally reverse response of these enzymes was observed during callus induction from three different explants. During shoot induction, catalase and peroxidase increased at high rate while there was a mild reduction in ascorbate peroxidase activity. Catalase and peroxidase continuously increased; on the other hand, ascorbate peroxidase activity decreased during root development and acclimatization states. The protocol described here can be employed for the mass propagation and genetic transformation of this rare herb. This study also highlights the importance and role of ascorbate peroxidase, catalase, and peroxidase in the establishment of A. roseum in vitro culture through callogenesis and organogenesis.

  9. Expression and Activation of Horseradish Peroxidase-Protein A/G Fusion Protein in Silkworm Larvae for Diagnostic Purposes.

    Science.gov (United States)

    Xxxx, Patmawati; Minamihata, Kosuke; Tatsuke, Tsuneyuki; Lee, Jae Man; Kusakabe, Takahiro; Kamiya, Noriho

    2018-06-01

    Recombinant protein production can create artificial proteins with desired functions by introducing genetic modifications to the target proteins. Horseradish peroxidase (HRP) has been used extensively as a reporter enzyme in biotechnological applications; however, recombinant production of HRP has not been very successful, hampering the utilization of HRP with genetic modifications. A fusion protein comprising an antibody binding protein and HRP will be an ideal bio-probe for high-quality HRP-based diagnostic systems. A HRP-protein A/G fusion protein (HRP-pAG) is designed and its production in silkworm (Bombyx mori) is evaluated for the first time. HRP-pAG is expressed in a soluble apo form, and is activated successfully by incubating with hemin. The activated HRP-pAG is used directly for ELISA experiments and retains its activity over 20 days at 4 °C. Moreover, HRP-pAG is modified with biotin by the microbial transglutaminase (MTG) reaction. The biotinylated HRP-pAG is conjugated with streptavidin to form a HRP-pAG multimer and the multimeric HRP-pAG produced higher signals in the ELISA system than monomeric HRP-pAG. The successful production of recombinant HRP in silkworm will contribute to creating novel HRP-based bioconjugates as well as further functionalization of HRP by applying enzymatic post-translational modifications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Modulation in radiation-induced changes in peroxidase activity with gibberellic acid in seedling's growth in chickpea (Cicer arietinum L.)

    International Nuclear Information System (INIS)

    Khan, M.R.; Qureshi, A.S.

    2002-01-01

    Changes in the effects of gamma irradiation (10 to 110 Kr) with gibberellic acid (GA/sub 3/) for peroxidase activity, in relation to early days of seedling's growth in Kabulic chickpea cultivar, Noor-91, were evaluated. Stimulation in peroxidase activity over control was recorded at all the irradiation treatments from 3rd to 8th day of seedling's development. Increase in peroxidase activity at 10 and 20 Kr was due to the increase in metabolic activity, while higher doses of gamma radiation account for the damaging action and production of peroxy radicals. However, stimulation in fresh weight was observed only at 10 Kr of gamma irradiation. Postmutagenic application of Ga/sub 3/ protect the seedlings from radiation injury, by increasing the peroxides activity, and increased the fresh weight of chickpea seedlings. (author)

  11. Detoxification enzymes activities in deltamethrin and bendiocarb ...

    African Journals Online (AJOL)

    Detoxification enzymes activities in deltamethrin and bendiocarb resistant and susceptible malarial vectors ( Anopheles gambiae ) breeding in Bichi agricultural and residential sites, Kano state, Nigeria.

  12. A Facile synthesis of superparamagnetic Fe3O4 nanofibers with superior peroxidase-like catalytic activity for sensitive colorimetric detection of L-cysteine

    Science.gov (United States)

    Chen, Sihui; Chi, Maoqiang; Zhu, Yun; Gao, Mu; Wang, Ce; Lu, Xiaofeng

    2018-05-01

    Superaramagnetic Fe3O4 nanomaterials are good candidates as enzyme mimics due to their excellent catalytic activity, high stability and facile synthesis. However, the morphology of Fe3O4 nanomaterials has much influence on their enzyme-like catalytic activity. In this work, we have developed a simple polymer-assisted thermochemical reduction approach to prepare Fe3O4 nanofibers for peroxidase-like catalytic applications. The as-prepared Fe3O4 nanofibers show a higher catalytic activity than commercial Fe3O4 nanoparticles. The steady-state kinetic assay result shows that the Michaelis-Menten constant value of the as-obtained Fe3O4 nanofibers is similar to that of horseradish peroxidase (HRP), indicating their superior affinity to the 3,3‧,5,5‧-tetramethylbenzidine (TMB) and H2O2 substrate. Based on the outstanding catalytic activity, a sensing platform for the detection of L-cysteine has been performed and the limit of detection is as low as 0.028 μM. In addition, an excellent selectivity toward L-cysteine over other types of amino acids, glucose and metal ions has been achieved as well. This work offers an original means for the fabrication of superparamagnetic Fe3O4 nanofibers and demonstrates their delightful potential applications in the fields of biosensing, environmental monitoring, and medical diagnostics.

  13. Colorimetric Glucose Assay Based on Magnetic Particles Having Pseudo-peroxidase Activity and Immobilized Glucose Oxidase.

    Science.gov (United States)

    Martinkova, Pavla; Opatrilova, Radka; Kruzliak, Peter; Styriak, Igor; Pohanka, Miroslav

    2016-05-01

    Magnetic particles (MPs) are currently used as a suitable alternative for peroxidase in the construction of novel biosensors, analytic and diagnostic methods. Their better chemical and thermal stabilities predestine them as appropriate pseudo-enzymatic catalysts. In this point of view, our research was focused on preparation of simply and fast method for immobilization of glucose oxidase onto surface of MPs with peroxidase-like activity. Spectrophotometric method (wavelength 450 nm) optimized for glucose determination using modified MPs has been successfully developed. Concentration curve for optimization of method was assayed, and Michaelis-Menten constant (K m) calculated, maximum reaction rate (V max), limit of detection, and correlation coefficient were determined to be 0.13 mmol/l (2.34 mg/dl), 1.79 pkat, 3.74 µmol/l (0.067 mg/dl), and 0.996, respectively. Interferences of other sugars such as sucrose, sorbitol, deoxyribose, maltose, and fructose were determined as well as effect of substances presenting in plasma (ascorbic acid, reduced glutathione, trolox, and urea). Results in comparison with positive and negative controls showed no interferences of the other sugars and no influence of plasma substances to measuring of glucose. The constructed method showed corresponding results with linear dependence and a correlation coefficient of 0.997. Possibility of repeated use of modified MPs was successfully proved.

  14. The effect of seedling chilling on glutathione content, catalase and peroxidase activity in Brassica oleracea L. var. italica

    Directory of Open Access Journals (Sweden)

    Renata Wojciechowska

    2013-09-01

    Full Text Available The study was designed to determine the possible relationship between Brassica oleracea var. italica seedlings stored at 2°C in the dark for seven and fourteen days, respectively, and the level of certain antioxidant parameters in particular organs. A parallel objective of the experiment was to determine if the reaction of seedlings to low temperature might be persistent in fully developed plants until harvest time. After 14 days of chilling a significant increase in the glutathione content was observed in the seedling leaves in comparison to the non-chilled plants. During vegetation in field conditions this effect was maintained in leaves up to the stage of formation of flower buds. At harvest the highest content of glutathione was demonstrated in broccoli heads, obtained from plants, which were previously chilled in the seedling phase for two weeks. Peroxidase activity in broccoli seedlings increased each year of the three-year study due to the duration of the cooling time, whereas in the case of catalase the changes were not so distinct. At harvest time the activity of both enzymes in the leaves and flower buds fluctuated according to the particular year of study.

  15. The peroxidase and oxidase-like activity of NiCo{sub 2}O{sub 4} mesoporous spheres: Mechanistic understanding and colorimetric biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Su, Li, E-mail: suli@htu.edu.cn [Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China); Henan Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Dong, Wenpei; Wu, Chengke; Gong, Yijun; Zhang, Yan; Li, Ling; Mao, Guojiang; Feng, Suling [Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007 (China); Henan Key Laboratory of Green Chemical Media and Reactions, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007 (China)

    2017-01-25

    The synthesized NiCo{sub 2}O{sub 4} mesoporous spheres (MS) displayed intrinsic peroxidase and oxidase-like activity were firstly reported. The catalytic mechanism of the oxidase-like activity of NiCo{sub 2}O{sub 4} MS was analyzed in detail using the electron spin resonance (ESR) method. It is found that NiCo{sub 2}O{sub 4} MS could directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) but did not produce {sup 1}O{sub 2} and ·OH. And the mechanism of the peroxidase-like activity of NiCo{sub 2}O{sub 4} MS was also verified that the oxidation of TMB stemmed from not only ·OH but also {sup 1}O{sub 2}. Based on the NiCo{sub 2}O{sub 4} MS showed excellent peroxidase-like activity over a broad temperature range, especially at normal body temperature, a detection tool was designed for glucose determination in diabetics' serum samples. And this detection method based on NiCo{sub 2}O{sub 4} MS gave a lower limit of detection than the method using Co{sub 3}O{sub 4} NPs and NiO NPs, as the single-component oxides of NiCo{sub 2}O{sub 4}. Our study may open up the possibility to make a great influence on the next generation of enzyme mimetics system. - Highlights: • NiCo{sub 2}O{sub 4} MS were found to possess the peroxidase and oxidase-like activity. • The peroxidase-like activity of NiCo{sub 2}O{sub 4} MS was stemmed from not only ·OH but also {sup 1}O{sub 2}. • The oxidase-like activity may stem from NiCo{sub 2}O{sub 4} MS′ oxidation rather than ·OH and {sup 1}O{sub 2}. • A colorimetric detection tool is designed for glucose determination in serum samples.

  16. Enzymes and Enzyme Activity Encoded by Nonenveloped Viruses.

    Science.gov (United States)

    Azad, Kimi; Banerjee, Manidipa; Johnson, John E

    2017-09-29

    Viruses are obligate intracellular parasites that rely on host cell machineries for their replication and survival. Although viruses tend to make optimal use of the host cell protein repertoire, they need to encode essential enzymatic or effector functions that may not be available or accessible in the host cellular milieu. The enzymes encoded by nonenveloped viruses-a group of viruses that lack any lipid coating or envelope-play vital roles in all the stages of the viral life cycle. This review summarizes the structural, biochemical, and mechanistic information available for several classes of enzymes and autocatalytic activity encoded by nonenveloped viruses. Advances in research and development of antiviral inhibitors targeting specific viral enzymes are also highlighted.

  17. Enzyme Activity Experiments Using a Simple Spectrophotometer

    Science.gov (United States)

    Hurlbut, Jeffrey A.; And Others

    1977-01-01

    Experimental procedures for studying enzyme activity using a Spectronic 20 spectrophotometer are described. The experiments demonstrate the effect of pH, temperature, and inhibitors on enzyme activity and allow the determination of Km, Vmax, and Kcat. These procedures are designed for teaching large lower-level biochemistry classes. (MR)

  18. Humanlike substitutions to Ω-loop D of yeast iso-1-cytochrome c only modestly affect dynamics and peroxidase activity.

    Science.gov (United States)

    Lei, Haotian; Bowler, Bruce E

    2018-06-01

    Structural studies of yeast iso-1-cytochrome c (L.J. McClelland, T.-C. Mou, M.E. Jeakins-Cooley, S.R. Sprang, B.E. Bowler, Proc. Natl. Acad. Sci. U.S.A. 111 (2014) 6648-6653) show that modest movement of Ω-loop D (residues 70-85, average RMSD versus the native structure: 0.81 Å) permits loss of Met80-heme ligation creating an available coordination site to catalyze the peroxidase activity mediated by cytochrome c early in apoptosis. However, Ala81 and Gly83 move significantly (RMSDs of 2.18 and 1.26 Å, respectively). Ala81 and Gly83 evolve to Ile and Val, respectively, in human cytochrome c and peroxidase activity decreases 25-fold relative to the yeast protein at pH 7. To test the hypothesis that these residues evolved to restrict the peroxidase activity of cytochrome c, A81I and G83V variants of yeast iso-1-cytochrome c were prepared. For both variants, the apparent pK a of the alkaline transition increases by 0.2 to 0.3 relative to the wild type (WT) protein and the rate of opening the heme crevice is slowed. The cooperativity of acid unfolding is decreased for the G83V variant. At pH 7 and 8, the catalytic rate constant, k cat , for the peroxidase activity of both variants decreases relative to WT, consistent with the effects on alkaline isomerization. Below pH 7, the loss in the cooperativity of acid unfolding causes k cat for peroxidase activity to increase for the G83V variant relative to WT. Neither variant decreases k cat to the level of the human protein, indicating that other residues also contribute to the low peroxidase activity of human cytochrome c. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Enzymes with activity toward Xyloglucan

    NARCIS (Netherlands)

    Vincken, J.P.

    2003-01-01

    Xyloglucans are plant cell wall polysaccharides, which belong to the hemicellulose class. Here the structural variations of xyloglucans will be reviewed. Subsequently, the anchoring of xyloglucan in the plant cell wall will be discussed. Enzymes involved in degradation or modification of xyloglucan

  20. Degradation kinetics of peroxidase enzyme, phenolic content, and physical and sensorial characteristics in broccoli (Brassica oleracea L. ssp. Italica) during blanching.

    Science.gov (United States)

    Gonçalves, Elsa M; Pinheiro, Joaquina; Alegria, Carla; Abreu, Marta; Brandão, Teresa R S; Silva, Cristina L M

    2009-06-24

    The effects of water blanching treatment on peroxidase inactivation, total phenolic content, color parameters [-a*/b* and hue (h degrees*)], texture (maximum shear force), and sensory attributes (color and texture, evaluated by a trained panel) of broccoli (Brassica oleracea L. ssp. Italica) were studied at five temperatures (70, 75, 80, 85, and 90 degrees C). Experimental results showed that all studied broccoli quality parameters suffered significative changes due to blanching treatments. The vegetal total phenolic content showed a marked decline. Degradation on objective color and texture measurements and alterations in sensorial attributes were detected. Correlations between sensory and instrumental measurements have been found. Under the conditions 70 degrees C and 6.5 min or 90 degrees C and 0.4 min, 90% of the initial peroxidase activity was reduced. At these conditions, no significant alterations were detected by panelists, and a small amount of phenolic content was lost (ca. 16 and 10%, respectively). The peroxidase inactivation and phenolic content degradation were found to follow first-order reaction models. The zero-order reaction model showed a good fit to the broccoli color (-a*/b* and h degrees*), texture, and sensory parameters changes. The temperature effect was well-described by the Arrhenius law.

  1. Coupled enzyme reactions performed in heterogeneous reaction media: experiments and modeling for glucose oxidase and horseradish peroxidase in a PEG/citrate aqueous two-phase system.

    Science.gov (United States)

    Aumiller, William M; Davis, Bradley W; Hashemian, Negar; Maranas, Costas; Armaou, Antonios; Keating, Christine D

    2014-03-06

    The intracellular environment in which biological reactions occur is crowded with macromolecules and subdivided into microenvironments that differ in both physical properties and chemical composition. The work described here combines experimental and computational model systems to help understand the consequences of this heterogeneous reaction media on the outcome of coupled enzyme reactions. Our experimental model system for solution heterogeneity is a biphasic polyethylene glycol (PEG)/sodium citrate aqueous mixture that provides coexisting PEG-rich and citrate-rich phases. Reaction kinetics for the coupled enzyme reaction between glucose oxidase (GOX) and horseradish peroxidase (HRP) were measured in the PEG/citrate aqueous two-phase system (ATPS). Enzyme kinetics differed between the two phases, particularly for the HRP. Both enzymes, as well as the substrates glucose and H2O2, partitioned to the citrate-rich phase; however, the Amplex Red substrate necessary to complete the sequential reaction partitioned strongly to the PEG-rich phase. Reactions in ATPS were quantitatively described by a mathematical model that incorporated measured partitioning and kinetic parameters. The model was then extended to new reaction conditions, i.e., higher enzyme concentration. Both experimental and computational results suggest mass transfer across the interface is vital to maintain the observed rate of product formation, which may be a means of metabolic regulation in vivo. Although outcomes for a specific system will depend on the particulars of the enzyme reactions and the microenvironments, this work demonstrates how coupled enzymatic reactions in complex, heterogeneous media can be understood in terms of a mathematical model.

  2. Analysis of the Peroxidase Activity of Rice (Oryza Sativa) Recombinant Hemoglobin 1: Implications for the In Vivo Function of Hexacoordinate Non-Symbiotic Hemoglobins in Plants

    Science.gov (United States)

    In plants, it has been proposed that hexacoordinate (class 1) non-symbiotic Hbs (nsHb-1) function in vivo as peroxidases. However, little is known about the peroxidase activity of nsHb-1. We evaluated the peroxidase activity of rice recombinant Hb1 (a nsHb-1) by using the guaiacol/H2O2 system at pH ...

  3. Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese

    Science.gov (United States)

    Franson, J. Christian; Hoffman, David J.; Schmutz, Joel A.

    2002-01-01

    In 1998, we collected blood samples from 63 emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feathermolting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.

  4. Ultrastructural cytochemical prospective study of adult acute lymphoblastic leukemia: detection of peroxidase activity in patients failing to respond to treatment.

    Science.gov (United States)

    Reiffers, J; Darmendrail, V; Larrue, J; Villenave, I; Bernard, P; Boisseau, M; Broustet, A

    1981-08-15

    Ultrastructural cytochemical studies revealed peroxidase activity in five of 25 adult patients with apparent null lymphoblastic leukemia (ALL) in whom the peroxidase reaction studied with light microscopy was negative. None of these 5 patients responded to a chemotherapy regimen used for adult ALL. The importance of ultrastructural cytochemistry which allows the recognition of myeloblastic differentiation in undifferentiated blast cells is also demonstrated. The correct classification of such cases may be important for prognosis because they appear to be resistant to the chemotherapy used in treating ALL.

  5. Antioxidant Enzyme Activities of some Brassica Species

    Directory of Open Access Journals (Sweden)

    Rodica SOARE

    2017-11-01

    Full Text Available This paper set out to comparatively study five species: white cabbage (Brassica oleracea L. var. capitata alba Alef., red cabbage (Brassica oleracea L. var. capitata f. rubra Alef., Kale (Brassica oleracea L. var. Acephala, cauliflower (Brassica oleracea var. botrytis and broccoli (Brassica oleracea var. cymosa in order to identify those with high enzymatic and antioxidant activities. The enzymatic activity of superoxide dismutase (SOD, catalase (CAT and soluble peroxidase (POX as well as the antioxidant activity against 2.2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS radical cation were determined. Total superoxide dismutase activity was measured spectrophotometrically based on inhibition in the photochemical reduction of nitroblue tetrazolium. Total soluble peroxidase was assayed by measuring the increase in A436 due to the guaiacol oxidation and the catalase activity was assayed through the colorimetric method. The capacity of extracts to scavenge the ABTS radical cation was assessed colorimetric using Trolox as a standard. The obtained results show that studied enzymatic activities and the antioxidant activity against ABTS vary depending on the analyzed species. So, among the studied Brassicaceae species, it emphasize red cabbage with the highest enzymatic activity (CAT 22.54 mM H2O2/min/g and POX 187.2 mM ΔA/1min/1g f.w. and kale with highest antioxidant activity, of 767 μmol TE/100g f.w. The results of this study recommendintroducing the studied varieties in diet due to the rich antioxidant properties.

  6. Purification and characterization of an intracellular catalase-peroxidase from Penicillium simplicissimum

    NARCIS (Netherlands)

    Fraaije, Marco W.; Roubroeks, Hanno P.; Hagen, Wilfred R.; Berkel, Willem J.H. van

    1996-01-01

    The first dimeric catalase-peroxidase of eucaryotic origin, an intracellular hydroperoxidase from Penicillium simplicissimum which exhibited both catalase and peroxidase activities, has been isolated. The enzyme has an apparent molecular mass of about 170 kDa and is composed of two identical

  7. ISOENZYMATIC POLYMORPHISM AND ACTIVITY OF PEROXIDASES OF COMMON BEAN (Phaseolus vulgaris L. UNDER SALINE STRESS

    Directory of Open Access Journals (Sweden)

    F. BROETTO

    1997-09-01

    Full Text Available One of the uses of the technique of tissue culture for plant breeding is the identification of cell lines tolerant to salt stress.In order to study the biochemical mechanisms involved in the genetic expression to salt tolerance, callus from embryo axis of four bean cultivars (cv. IAC-carioca; cv. IAPAR-14; cv. JALO-EEP558; CV. BAT-93 were grown in Murashige & Skoog (1962 medium, supplemented with NaCl in the concentrations of 0, 20, 40, 60 and 80 mM. After 14 days callus were harvested and analyzed according to their isoenzymatic patterns and peroxidase activities. BAT and IAPAR cultivars showed two common activity zones in the anodic region, with only one specific enzymatic band to each one (the two fastest migration band; it is possible that the two middle anodic zones detected are products of the same enzymatic locus but from different alleles with different eletrophoretic mobilities. Cv. JALO showed two anodic activities in common with cvs IAC and IAPAR with an exclusive anodic zone of slower migration which showed the most intense activity of all cultivars analyzed. This cv. still showed a dimeric heterozygotic catodic zone in all treated samples. Probably this is the same zone which occurs in homozygosis with fixation of the slower allele for all cvs BAT and IAPAR submitted to all treatments. Cv. IAC showed two anodic bands in common with Cv. IAPAR and cv. JALO. It still showed a faster anodic band in common with cv. IAPAR and an exclusive anodic band of slower migration. It is interesting to say that for this cv. IAC resulting from cultivation in NaCl 20 mM did not show activity in the three slower anodic zones. Cv. IAC showed only one dimeric heterozygotic catodic zone in all treatments. This zone is probably composed by two different alleles from the same locus detected in cv. JALO. Samples from cv. IAC treated with 40 and 60 mM showed a more intense enzymatic activity in the catodic zone. Analyses of the peroxidase activity in the

  8. Guaiacol peroxidase zymography for the undergraduate laboratory.

    Science.gov (United States)

    Wilkesman, Jeff; Castro, Diana; Contreras, Lellys M; Kurz, Liliana

    2014-01-01

    This laboratory exercise presents a novel way to introduce undergraduate students to the specific detection of enzymatic activity by electrophoresis. First, students prepare a crude peroxidase extract and then analyze the homogenate via electrophoresis. Zymography, that is, a SDS-PAGE method to detect enzyme activity, is used to specifically detect peroxidase activity and furthermore, to analyze the total protein profile. After the assay, students may estimate the apparent molecular mass of the enzyme and discuss its structure. After the 4-h experiment, students gain knowledge concerning biological sample preparation, gel preparation, electrophoresis, and the importance of specific staining procedures for the detection of enzymatic activity. Copyright © 2014 The International Union of Biochemistry and Molecular Biology.

  9. Effect of cholesterol feeding on tissue lipid perioxidation, glutathione peroxidase activity and liver microsomal functions in rats and guinea pigs

    NARCIS (Netherlands)

    TSAI, A. C.; THIE, G. M.; Lin, C. R.

    1977-01-01

    The effect of cholesterol feeding on liver and aortic nonenzymatic lipid peroxidation and glutathione peroxidase activities, and on liver microsomal NADPH-dependent lipid peroxidation, codeine hydroxylation and cytochrome P-450 levels was examined in rats and guinea pigs. One percent cholesterol was

  10. COMPARED ANALYSIS OF CATALASE AND PEROXIDASE ACTIVITY IN CELLULOLYTIC FUNGUS TRICHODERMA REESEI GROWN ON MEDIUM WITH DIFFERENT CONCENTRATIONS OF GRINDED WHEAT AND BARLEY STRAWS

    Directory of Open Access Journals (Sweden)

    Mihaela Cristica

    2010-09-01

    Full Text Available The purpose of this study was to assess the evolution of catalase and peroxidase activity in Trichoderma reesei grown on medium containing grinded wheat and barley straws. Carbon source of cultivation medium - glucose was replaced by various concentrations of grinded wheat and barley straws, finally resulting three experimental variants as follows: V1 = 20 g/l, V2 = 30 g/l, V3 = 40 g/l. ĂŽn addition to these variants a control sample was added in which composition remainded unchanged. The catalase activity was determined by spectrophotometric Sinha method (Artenie et al., 2008 while peroxidase activity was assesed using the o-dianisidine method (Cojocaru, 2009. Enzymatic determinations were carried out at 7 and 14 days from inoculation, in both fungus mycelium and culture liquid. The enzymatic assay showed significant differences between determinations intervals and work variants. Enzyme activity is influenced by the age of fungus and by the different nature of the substrate used.

  11. Atividade peroxidásica em basófilos de Phrynops geoffroanus (Testudines Chelidae Peroxidase activity in the basophils of Phrynops geoffroanus (Testudines: Chelidae

    Directory of Open Access Journals (Sweden)

    Maria Isabel Afonso da Silva

    2010-01-01

    Full Text Available As peroxidases, presentes nos peroxissomos e lisossomos, pertencem às oxidases e atuam como catalítico para o peróxido de hidrogênio (H2O2, posteriormente decomposto pela oxidação de cossubstratos, evitando danos celulares.(¹ Foi aplicada a técnica da peroxidase(2 em esfregaços sanguíneos de Phrynops geoffroanus, comparando com sangue humano, para avaliação da atividade e controle da reação. O esfregaço sanguíneo humano apresentou marcações em neutrófilos, fagócitos com muitos lisossomos e peroxissomos (Figura 1. Nos esfregaços sanguíneos de Phrynops geoffroanus, as marcações apresentaram-se nos basófilos (Figura 2, que representam de 10% a 25% dos leucócitos de quelônios e possuem grande número de granulações citoplasmáticas,(3 sugerindo a presença de grande quantidade de enzimas e organelas como lisossomos e peroxissomos, possivelmente associadas a sua participação em reações imunes. A atividade peroxidásica representa resposta do organismo a ações ambientais danosas, servindo como marcador biológico.Peroxidase, present in peroxisomes and lysosomes, belongs to the oxidases and acts as a catalyst for hydrogen peroxide (H2O2 and is later decomposed by oxidation of cosubstrates thereby preventing cell damage.(1 The peroxidase technique(2 was applied to blood smears of Phrynops geoffroanus and the results compared with human blood to evaluate the activity and control of the reaction. The human blood film showed markings in neutrophils and phagocytes with many lysosomes and peroxisomes (Figure 1. In blood smears of Phrynops geoffroanus, the markings were on the basophils (Figure 2, that represent 10% to 25% of leukocytes of turtles and have a large number of cytoplasmatic granules(3 suggesting the presence of large amounts of enzymes and organelles such as lysosomes and peroxisomes, possibly associated with their participation in immune reactions. Peroxidase activity is the body's response to harmful

  12. Unveiling the water-associated conformational mobility in the active site of ascorbate peroxidase.

    Science.gov (United States)

    Chao, Wei-Chih; Lin, Li-Ju; Lu, Jyh-Feng; Wang, Jinn-Shyan; Lin, Tzu-Chieh; Chen, Yi-Han; Chen, Yi-Ting; Yang, Hsiao-Ching; Chou, Pi-Tai

    2018-03-01

    We carried out comprehensive spectroscopic studies of wild type and mutants of ascorbate peroxidase (APX) to gain understanding of the conformational mobility of the active site. In this approach, three unnatural tryptophans were applied to replace the distal tryptophan (W41) in an aim to probe polarity/water environment near the edge of the heme-containing active site. 7-azatryptophan ((7-aza)Trp) is sensitive to environment polarity, while 2,7-azatryptophan ((2,7-aza)Trp) and 2,6-diazatryptophan ((2,6-aza)Trp) undergo excited-state water-catalyzed double and triple proton transfer, respectively, and are sensitive to the water network. The combination of their absorption, emission bands and the associated relaxation dynamics of these fluorescence probes, together with the Soret-band difference absorption and resonance Raman spectroscopy, lead us to unveil the water associated conformational mobility in the active site of APX. The results are suggestive of the existence of equilibrium between two different environments surrounding W41 in APX, i.e., the water-rich and water-scant forms with distinct fluorescence relaxation. Our results thus demonstrate for the first time the power of integrating multiple sensors (7-aza)Trp, (2,7-aza)Trp and (2,6-aza)Trp in probing the water environment of a specifically targeted Trp in proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. The effects of selenium on glutathione peroxidase activity and radioprotection in mammalian cells

    International Nuclear Information System (INIS)

    Diamond, A.M.; Murray, J.L.; Dale, P.; Tritz, R.; Grdina, D.J.

    1995-01-01

    The media of representative mammalian cell lines were supplemented with low levels of selenium in the form of sodium selenite in order to investigate the effects of selenium on mammalian cells. Following incubation in 30 nM sodium selenite, these cells were assayed for changes in glutathione peroxidase (GPx) activity. The cells examined included NIH 3T3 mouse fibroblasts, PC12 rat sympathetic precursor cells, SupT-1 human lymphocytes, MCF-7 adr human breast carcinoma cells and AA8 Chinese hamster ovary cells. Selenium supplementation resulted in a marginal increase in GPx activity for the NIH 3T3, MCF-7 adr and Supt-1 cells but stimulated GPx activity approximately 5-fold in PC12 and AA8 cells. AA8 cells were selected to evaluate whether selenium supplementation was radioprotective against 60 cobalt gamma irradiation. Protection against radiation-induced mutation was measured by evaluating mutation frequency at the hprt locus. In this assay, preincubation of AA8 CHO cells significantly protected these cells from exposure to 8 Gy

  14. Visualization of enzyme activities inside earthworm pores

    Science.gov (United States)

    Hoang, Duyen; Razavi, Bahar S.

    2015-04-01

    In extremely dynamic microhabitats as bio-pores made by earthworm, the in situ enzyme activities are assumed as a footprint of complex biotic interactions. Our study focused on the effect of earthworm on the enzyme activities inside bio-pores and visualizing the differences between bio-pores and earthworm-free soil by zymography technique (Spohn and Kuzyakov, 2013). For the first time, we aimed at quantitative imaging of enzyme activities in bio-pores. Lumbricus terrestris L. was placed into transparent box (15×20×15cm). After two weeks when bio-pore systems were formed by earthworms, we visualized in situ enzyme activities of five hydrolytic enzymes (β-glucosidase, cellobiohydrolase, chitinase, xylanase, leucine-aminopeptidase, and phosphatase. Zymography showed higher activity of β-glucosidase, chitinase, xylanase and phosphatase in biopores comparing to bulk soil. However, the differences in activity of cellobiohydrolase and leucine aminopeptidase between bio-pore and bulk soil were less pronounced. This demonstrated an applicability of zymography approach to monitor and to distinguish the in situ activity of hydrolytic enzymes in soil biopores.

  15. The ultrasound technology for modifying enzyme activity

    Directory of Open Access Journals (Sweden)

    Meliza Lindsay Rojas

    2016-01-01

    Full Text Available Enzymes are protein complexes compounds widely studied and used due to their ability to catalyze reactions. The food processing mainly a ims the inactivation of enzymes due to various undesirable effects. However, there are many processes that can be optimized by its catalytic activity. In this context, different technologies have been applied both to inactivate or to improve the enzymes ef ficiency. The Ultrasound technology emerges as an alternative mainly applied to achieve the enzyme inactivation. On the contrary, very few investigations show the ability of this technology under certain conditions to achieve the opposite effect (i.e. increase the catalytic activity of enzymes. The objective of this study was to correlate the ultrasonic energy delivered to the sample (J/mL with the residual enzymatic activity and explain the possible mechanisms which results in the enzymatic activation/in activation complex behavior. The activity of POD in coconut water was evaluated as a model. The enzymatic activity initially increased, followed by reduction with a trend to enzyme inactivation. This complex behavior is directly related to the applied ultr asonic energy and their direct mechanical effects on the product, as well as the effect in the enzymatic infinite intermediate states and its structural conformation changes. The obtained results are useful for both academic and industrial perspectives.

  16. Mechanism of the reaction of ebselen with endogenous thiols : dihydrolipoate is a better cofactor than glutathione in the peroxidase activity of ebselen

    NARCIS (Netherlands)

    Haenen, G R; De Rooij, B M; Vermeulen, N P; Bast, A

    The therapeutic effect of ebselen has been linked to its peroxidase activity. In the present study, the peroxidase activity of ebselen toward H2O2 with the endogenous thiols GSH and dihydrolipoate [L(SH)2] as cofactors was determined. When GSH was used, peroxide removal was described by a ter uni

  17. Obtenção de nova fonte de peroxidase de folha de Copaifera langsdorffii Desf. com alta atividade Obtention of a new source of peroxidase from Copaifera langsdorffii leaf, Desf. with high activity

    Directory of Open Access Journals (Sweden)

    Hermelinda Penha Freire Maciel

    2006-12-01

    Full Text Available Objetivou-se neste trabalho extrair peroxidase de folha de Copaifera langsdorffii (COP, medir sua atividade, compará-la com a peroxidase de raiz forte (Horseradish peroxidase - HRP e determinar o pH ótimo, a melhor solução extratora e o efeito de aditivos sobre a atividade da COP. Os resultados mostraram que a COP atingiu 81,6% da atividade de HRP e a faixa de pH ótimo foi de 5,5 a 6,0. A melhor solução extratora da enzima foi o tampão fosfato de sódio 50 mM, pH 6,0 e o melhor aditivo foi o PVPP. Concluindo, a COP apresenta atividade mais alta que outras peroxidases de diferentes fontes citadas na literatura.The purpose of this work was to extract peroxidase from Copaifera langsdorffii leaves (COP, measure its activity, compare it to that of Horseradish peroxidase and determine the optimum pH, the best extraction solution and the effect of additives on the COP activity. The results showed that COP has 81.6% of the activity of HRP and an optimum pH range between 5.5-6.0. The best extraction solution was a sodium phosphate buffer 50 mM, pH 6.0 and the best additive was PVPP. In conclusion, COP presents higher activity than peroxidases from different sources reported in the literature.

  18. The ultrasound technology for modifying enzyme activity

    Directory of Open Access Journals (Sweden)

    Meliza Lindsay

    2016-06-01

    Full Text Available Enzymes are protein complexes compounds widely studied and used due to their ability to catalyze reactions. The food processing mainly aims the inactivation of enzymes due to various undesirable effects. However, there are many processes that can be optimized by its catalytic activity. In this context, different technologies have been applied both to inactivate or to improve the enzymes efficiency. The Ultrasound technology emerges as an alternative mainly applied to achieve the enzyme inactivation. On the contrary, very few investigations show the ability of this technology under certain conditions to achieve the opposite effect (i.e. increase the catalytic activity of enzymes. The objective of this study was to correlate the ultrasonic energy delivered to the sample (J/mL with the residual enzymatic activity and explain the possible mechanisms which results in the enzymatic activation/inactivation complex behavior. The activity of POD in coconut water was evaluated as a model. The enzymatic activity initially increased, followed by reduction with a trend to enzyme inactivation. This complex behavior is directly related to the applied ultrasonic energy and their direct mechanical effects on the product, as well as the effect in the enzymatic infinite intermediate states and its structural conformation changes. The obtained results are useful for both academic and industrial perspectives.

  19. Lysosomal enzyme activation in irradiated mammary tumors

    International Nuclear Information System (INIS)

    Clarke, C.; Wills, E.D.

    1976-01-01

    Lysosomal enzyme activity of C3H mouse mammary tumors was measured quantitatively by a histochemical method. Following whole-body doses of 3600 rad or less no changes were observed in the lysosomal enzyme activity for 12 hr after the irradiation, but very large increases in acid phosphatase and β-naphthylamidase activity were, however, observed 24 hr after irradiation. Significant increases in enzyme activity were detected 72 hr after a dose of 300 rad and the increases of enzyme activity were dose dependent over the range 300 to 900 rad. Testosterone (80 mg/kg) injected into mice 2 hr before irradiation (850 rad) caused a significant increase of lysosomal enzyme activity over and above that of the same dose of irradiation alone. If the tumor-bearing mice were given 95 percent oxygen/5 percent carbon dioxide to breathe for 8 min before irradiation the effect of 850 rad on lysosomal acid phosphatase was increased to 160 percent/that of the irradiation given alone. Activitation of lysosomal enzymes in mammary tumors is an important primary or secondary consequence of radiation

  20. Differences in wound-induced changes in cell-wall peroxidase activities and isoform patterns between seedlings of Prosopis tamarugo and Prosopis chilensis.

    Science.gov (United States)

    Lehner, Gabriele; Cardemil, Liliana

    2003-05-01

    We determined changes in cell-wall peroxidase activities and isoform patterns in response to wounding in seedlings of Prosopis tamarugo Phil. (an endemic species of the Atacama Desert) and Prosopis chilensis (Mol.) Stuntz (a native species of central Chile), to assess tolerance to predation. In seedlings of both species, the maximal increase in peroxidase activity occurred 48 h after wounding, reaching three times the control value in P. tamarugo and twice the control value in P. chilensis. The activity of ionically bound cell-wall peroxidases increased only locally in wounded embryonic axes, whereas the activity of soluble peroxidases increased systemically in unwounded cotyledons. Analysis of ionic peroxidases by isoelectrofocusing revealed two groups of peroxidases in the cell walls of both species: four distinct acidic isoforms and a group of basic isoforms. In response to wounding, there was a large increase in activity of the acidic isoforms in P. tamarugo, whereas there was an increase in the activity of the basic isoforms in P. chilensis. In P. chilensis, the wound-induced increase in activity of the basic isoforms corresponded with one of the two isoforms detected in P. tamarugo prior to wounding. Experiments with protein and RNA synthesis inhibitors indicated that a preexisting basic peroxidase is activated in P. chilensis after wounding. Assays of ionically bound peroxidase activity with four different substrates corroborated the differences found in isoform patterns between species. In P. tamarugo, the largest increases in activity were found with ortho-phenylenediamine and ferulic acid as substrates, whereas in P. chilensis the largest increase in activity was found with guaiacol as substrate. Because the same basic cell-wall peroxidase that accumulated after wounding in P. chilensis was present in P. tamarugo prior to wounding, and the activity of acidic cell-wall peroxidases increased after wounding in P. tamarugo but not in P. chilensis, we conclude

  1. Protective Antioxidant Enzyme Activities are Affected by Drought in Quinoa (Chenopodium Quinoa Willd)

    DEFF Research Database (Denmark)

    Fghire, Rachid; Ali, Oudou Issa; Anaya, Fatima

    2013-01-01

    Changes in water availability are responsible for a variety of biochemical stress responses in plant organisms. Stress induced by this factor may be associated with enhanced reactive oxygen species (ROS) generations, which cause oxidative damage. In the present study we investigated the activities...... increased in all treatments. These results suggest that antioxidant enzymes play important roles in reducing oxidative stress in quinoa plant exposed to drought stress....... of antioxidant enzymes superoxide dismutase (SOD), polyphenoloxydase (PPO), peroxidase (POD) and catalase (CAT), measured at flowering in quinoa, subjected to varying levels of drought stress. Drought levels were 100, 50 and 33% of evapotranspiration (ETc), and rainfed. Compared to full water supply (100%ETc...

  2. Modulation of the Activities of Catalase, Cu-Zn, Mn Superoxide Dismutase, and Glutathione Peroxidase in Adipocyte from Ovariectomised Female Rats with Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Rebeca Cambray Guerra

    2014-01-01

    Full Text Available The aim of this study was to evaluate the association between estrogen removal, antioxidant enzymes, and oxidative stress generated by obesity in a MS female rat model. Thirty two female Wistar rats were divided into 4 groups: Control (C, MS, MS ovariectomized (Ovx, and MS Ovx plus estradiol (E2. MS was induced by administering 30% sucrose to drinking water for 24 weeks. After sacrifice, intra-abdominal fat was dissected; adipocytes were isolated and lipid peroxidation, non-enzymatic antioxidant capacity, and the activities of Cu-Zn and Mn superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GPx were determined. There were no significant differences in the activities of Cu-Zn, Mn SOD, CAT, and GPx between the C and MS groups, but in the MS Ovx group there was a statistically significant decrease in the activities of these enzymes when compared to MS and MS Ovx+E2. The increased lipid peroxidation and nonenzymatic antioxidant capacity found in MS Ovx was significantly decreased when compared to MS and MS Ovx+E2. In conclusion, the removal of E2 by ovariectomy decreases the activity of the antioxidant enzymes in the intra-abdominal tissue of MS female rats; this is reflected by increased lipid peroxidation and decreased nonenzymatic antioxidant capacity.

  3. Antimutagenic activity of oxidase enzymes

    International Nuclear Information System (INIS)

    Agabeili, R.A.

    1986-01-01

    By means of a cytogenetic analysis of chromosomal aberrations in plant cells (Welsh onion, wheat) it was found that the cofactors nicotinamide adenine phosphate (NAD), nicotinamide adenine dinucleotide phosphate (NADPH), and riboflavin possess antimutagenic activity

  4. Efeito do cobre na atividade da enzima pirogalol peroxidase em plantas de Myriophyllum aquaticum cultivadas em solução nutritiva Effect of copper on the activity of pirogalol peroxidase in Myriophyllum aquaticum plants cultivated in nutritives solution

    Directory of Open Access Journals (Sweden)

    V.D. Domingos

    2005-06-01

    . The objective of the present work was to verify the effect of copper on the activity of pirogalol peroxidase in M. aquaticum plants submitted to nutritive solution containing copper concentrations of 1.2; 11.2; 21.2; 31.2 and 41.2 µg L-1. The experiment was carried out in a randomized complete design with 4 replicates and 5 treatments for 21 days Eighty-one days later, the leaves were collected starting from the apex of the plant to the end of the branch, which was not in contact with the solution. This fresh material was involved by transparent plastic and aluminum foil, frozen in liquid nitrogen, stored in freezer to -20 °C until determination of the enzyme activity. Enzyme activity increased with the increase of the copper doses. The plants cultivated with 40 µg L-1 of Cu2+ showed a reduced development, after three weeks, based on visual examination..

  5. Enzyme Enzyme activities in relation to sugar accumulation in tomato

    International Nuclear Information System (INIS)

    Alam, M.J.; Rahman, M.H.; Mamun, M.A.; Islam, K.

    2006-01-01

    Enzyme activities in tomato juice of five different varieties viz. Ratan, Marglove, BARI-1, BARI-5 and BARI-6, in relation to sugar accumulation were investigated at different maturity stages. The highest amount of invertase and beta-galactosidase was found in Marglove and the lowest in BARI- 6 at all maturity stages. Total soluble sugar and sucrose contents were highest in BARI-1 and lowest in BARI-6. The activity of amylase was maximum in Ratan and minimum in Marglove. Protease activity was highest in Ratan and lowest in BARI-6. BARI-1 contained the highest cellulase activity and the lowest in BARI-5. The amount of total soluble sugar and sucrose increased moderately from premature to ripe stage. The activities of amylase and cellulase increased up to the mature stage and then decreased drastically in the ripe stage. The activities of invertase and protease increased sharply from the premature to the ripe stage while the beta-galactosidase activity decreased remarkably. No detectable amount of reducing sugar was present in the premature stage in all cultivars of tomato but increased thereafter upto the ripe stage. The highest reducing sugar was present in BARI-5 in all of the maturity stages. (author)

  6. Direct Electrochemistry of Horseradish Peroxidase on NiO Nanoflower Modified Electrode and Its Electrocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Lijun Yan

    2016-09-01

    Full Text Available In this paper nickel oxide (NiO nanoflower was synthesized and used for the realization of direct electrochemistry of horseradish peroxidase (HRP. By using carbon ionic liquid electrode (CILE as the substrate electrode, NiO-HRP composite was casted on the surface of CILE with chitosan (CTS as the film forming material and the modified electrode was denoted as CTS/NiO-HRP/CILE. UV-Vis absorption and FT-IR spectra confirmed that HRP retained its native structure after mixed with NiO nanoflower. Direct electron transfer of HRP on the modified electrode was investigated by cyclic voltammetry with a pair of quasi-reversible redox waves appeared, indicating that the presence of NiO nanoflower on the electrode surface could accelerate the electron transfer rate between the electroactive center of HRP and the substrate electrode. Electrochemical behaviors of HRP on the modified electrode were carefully investigated. The HRP modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid with wider linear range and lower detection limit. Therefore the presence of NiO nanoflower could provide a friendly biocompatible interface for immobilizing biomolecules and keeping their native structure. The fabricated electrochemical biosensor displayed the advantages such as high sensitivity, good reproducibility and long-term stability. This work is licensed under a Creative Commons Attribution 4.0 International License.

  7. Betacyanin accumulation and guaiacol peroxidase activity in Beta vulgaris L. leaves following copper stress

    Directory of Open Access Journals (Sweden)

    Janet M. León Morales

    2012-07-01

    Full Text Available The effect of copper stress on betacyanin accumulation and guaiacol peroxidase (GPOD activity in leaves of different age was evaluated in red beet (Beta vulgaris L. var. Crosby Egyptian plants. In hydroponic culture, plants were treated with 0.3 μM (control, 50 μM, 100 μM, and 250 μM of CuSO4 for 6 days. Copper was taken up and accumulated in old roots but was not translocated to leaves. However in young leaves, the increase of lipid peroxidation and reduction of growth were evident from day 3 of copper exposure; whereas in old leaves, the lipid peroxidation and growth were the same from either copper-treated or control plants. In response to copper exposure, the betacyanin accumulation was evident in young leaves by day 3, and continued to increase until day 6. Betacyanin only were accumulated in old leaves until day 6, but the contents were from 4 to 5 times lower than those observed in young leaves at the same copper concentrations. GPOD activity increased 3.3- and 1.4-fold in young and old leaves from day 3 of copper treatment respectively, but only in the young leaves was sustained at the same level until day 6. Old roots shown betacyanin in the control plants, but the betacyanin level and growth were reduced with the copper exposure. In contrast, young roots emerged by copper effect also accumulated copper and showed the highest betacyanin content of all plant parts assayed. These results indicate that betacyanin accumulation and GPOD activity are defense responses to copper stress in actively growing organs.

  8. Oxidations of N-(3-indoleethyl) cyclic aliphatic amines by horseradish peroxidase: the indole ring binds to the enzyme and mediates electron-transfer amine oxidation.

    Science.gov (United States)

    Ling, Ke-Qing; Li, Wen-Shan; Sayre, Lawrence M

    2008-01-23

    Although oxidations of aromatic amines by horseradish peroxidase (HRP) are well-known, typical aliphatic amines are not substrates of HRP. In this study, the reactions of N-benzyl and N-methyl cyclic amines with HRP were found to be slow, but reactions of N-(3-indoleethyl) cyclic amines were 2-3 orders of magnitude faster. Analyses of pH-rate profiles revealed a dominant contribution to reaction by the amine-free base forms, the only species found to bind to the enzyme. A metabolic study on a family of congeneric N-(3-indoleethyl) cyclic amines indicated competition between amine and indole oxidation pathways. Amine oxidation dominated for the seven- and eight-membered azacycles, where ring size supports the change in hybridization from sp3 to sp2 that occurs upon one-electron amine nitrogen oxidation, whereas only indole oxidation was observed for the six-membered ring congener. Optical difference spectroscopic binding data and computational docking simulations suggest that all the arylalkylamine substrates bind to the enzyme through their aromatic termini with similar binding modes and binding affinities. Kinetic saturation was observed for a particularly soluble substrate, consistent with an obligatory role of an enzyme-substrate complexation preceding electron transfer. The significant rate enhancements seen for the indoleethylamine substrates suggest the ability of the bound indole ring to mediate what amounts to medium long-range electron-transfer oxidation of the tertiary amine center by the HRP oxidants. This is the first systematic investigation to document aliphatic amine oxidation by HRP at rates consistent with normal metabolic turnover, and the demonstration that this is facilitated by an auxiliary electron-rich aromatic ring.

  9. Probucol increases striatal glutathione peroxidase activity and protects against 3-nitropropionic acid-induced pro-oxidative damage in rats.

    Directory of Open Access Journals (Sweden)

    Dirleise Colle

    Full Text Available Huntington's disease (HD is an autosomal dominantly inherited neurodegenerative disease characterized by symptoms attributable to the death of striatal and cortical neurons. The molecular mechanisms mediating neuronal death in HD involve oxidative stress and mitochondrial dysfunction. Administration of 3-nitropropionic acid (3-NP, an irreversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, in rodents has been proposed as a useful experimental model of HD. This study evaluated the effects of probucol, a lipid-lowering agent with anti-inflammatory and antioxidant properties, on the biochemical parameters related to oxidative stress, as well as on the behavioral parameters related to motor function in an in vivo HD model based on 3-NP intoxication in rats. Animals were treated with 3.5 mg/kg of probucol in drinking water daily for 2 months and, subsequently, received 3-NP (25 mg/kg i.p. once a day for 6 days. At the end of the treatments, 3-NP-treated animals showed a significant decrease in body weight, which corresponded with impairment on motor ability, inhibition of mitochondrial complex II activity and oxidative stress in the striatum. Probucol, which did not rescue complex II inhibition, protected against behavioral and striatal biochemical changes induced by 3-NP, attenuating 3-NP-induced motor impairments and striatal oxidative stress. Importantly, probucol was able to increase activity of glutathione peroxidase (GPx, an enzyme important in mediating the detoxification of peroxides in the central nervous system. The major finding of this study was that probucol protected against 3-NP-induced behavioral and striatal biochemical changes without affecting 3-NP-induced mitochondrial complex II inhibition, indicating that long-term probucol treatment resulted in an increased resistance against neurotoxic events (i.e., increased oxidative damage secondary to mitochondrial dysfunction. These data appeared to be of great

  10. An investigation of the mimetic enzyme activity of two-dimensional Pd-based nanostructures

    Science.gov (United States)

    Wei, Jingping; Chen, Xiaolan; Shi, Saige; Mo, Shiguang; Zheng, Nanfeng

    2015-11-01

    In this work, we investigated the mimetic enzyme activity of two-dimensional (2D) Pd-based nanostructures (e.g. Pd nanosheets, Pd@Au and Pd@Pt nanoplates) and found that they possess intrinsic peroxidase-, oxidase- and catalase-like activities. These nanostructures were able to activate hydrogen peroxide or dissolved oxygen for catalyzing the oxidation of organic substrates, and decompose hydrogen peroxide to generate oxygen. More systematic investigations revealed that the peroxidase-like activities of these Pd-based nanomaterials were highly structure- and composition-dependent. Among them, Pd@Pt nanoplates displayed the highest peroxidase-like activity. Based on these findings, Pd-based nanostructures were applied for the colorimetric detection of H2O2 and glucose, and also the electro-catalytic reduction of H2O2. This work offers a promising prospect for the application of 2D noble metal nanostructures in biocatalysis.In this work, we investigated the mimetic enzyme activity of two-dimensional (2D) Pd-based nanostructures (e.g. Pd nanosheets, Pd@Au and Pd@Pt nanoplates) and found that they possess intrinsic peroxidase-, oxidase- and catalase-like activities. These nanostructures were able to activate hydrogen peroxide or dissolved oxygen for catalyzing the oxidation of organic substrates, and decompose hydrogen peroxide to generate oxygen. More systematic investigations revealed that the peroxidase-like activities of these Pd-based nanomaterials were highly structure- and composition-dependent. Among them, Pd@Pt nanoplates displayed the highest peroxidase-like activity. Based on these findings, Pd-based nanostructures were applied for the colorimetric detection of H2O2 and glucose, and also the electro-catalytic reduction of H2O2. This work offers a promising prospect for the application of 2D noble metal nanostructures in biocatalysis. Electronic supplementary information (ESI) available: TEM images, EDX and dispersion stability of Pd-based nanomaterials

  11. Activity assessment of microbial fibrinolytic enzymes.

    Science.gov (United States)

    Kotb, Essam

    2013-08-01

    Conversion of fibrinogen to fibrin inside blood vessels results in thrombosis, leading to myocardial infarction and other cardiovascular diseases. In general, there are four therapy options: surgical operation, intake of antiplatelets, anticoagulants, or fibrinolytic enzymes. Microbial fibrinolytic enzymes have attracted much more attention than typical thrombolytic agents because of the expensive prices and the side effects of the latter. The fibrinolytic enzymes were successively discovered from different microorganisms, the most important among which is the genus Bacillus. Microbial fibrinolytic enzymes, especially those from food-grade microorganisms, have the potential to be developed as functional food additives and drugs to prevent or cure thrombosis and other related diseases. There are several assay methods for these enzymes; this may due to the insolubility of substrate, fibrin. Existing assay methods can be divided into three major groups. The first group consists of assay of fibrinolytic activity with natural proteins as substrates, e.g., fibrin plate methods. The second and third groups of assays are suitable for kinetic studies and are based on the determination of hydrolysis of synthetic peptide esters. This review will deal primarily with the microorganisms that have been reported in literature to produce fibrinolytic enzymes and the first review discussing the methods used to assay the fibrinolytic activity.

  12. Studies of peroxidase isozyme profile in mungbean mutants

    International Nuclear Information System (INIS)

    Auti, S.G.; Apparao, B.J.

    2007-01-01

    Peroxidase is an important oxygen-scavenging enzyme. The activity of peroxidase is often correlated with growth, development and hormonal activity. Traditional methods of cultivar identification usually involve observation and recording of morphological characters or description such as yield, height, weight, earliness etc. which vary with environmental conditions and often misleading. So molecular markers like protein and isozymes profiles, RFLP, RAPDs markers etc. are widely employed in varietal identification of cultivars. It plays important role in respiration and is an indicator of oxidative status of plants. Electrophoretic techniques have been used to group species and identify cultivars. Such identification has various advantages including the unique pattern of protein or isozymes bands for each pure cultivar under any set of environmental conditions. Peroxidase isozyme serves as very good marker for any mutational studies. In the present investigation, peroxidase isozyme profiles of various mutants of mungbean was studied employing the technique of electrophoresis

  13. Changes in element accumulation, phenolic metabolism, and antioxidative enzyme activities in the red-skin roots of Panax ginseng.

    Science.gov (United States)

    Zhou, Ying; Yang, Zhenming; Gao, Lingling; Liu, Wen; Liu, Rongkun; Zhao, Junting; You, Jiangfeng

    2017-07-01

    Red-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng). To explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate-glutathione cycle were examined using conventional methods. Aluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of H 2 O 2 and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of l-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione- S -transferase activity remained constant. Hence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate-glutathione cycles, are activated to protect against phenolic compound

  14. Enzyme specific activity in functionalized nanoporous supports

    International Nuclear Information System (INIS)

    Lei Chenghong; Soares, Thereza A; Shin, Yongsoon; Liu Jun; Ackerman, Eric J

    2008-01-01

    Here we reveal that enzyme specific activity can be increased substantially by changing the protein loading density (P LD ) in functionalized nanoporous supports so that the enzyme immobilization efficiency (I e , defined as the ratio of the specific activity of the immobilized enzyme to the specific activity of the free enzyme in solution) can be much higher than 100%. A net negatively charged glucose oxidase (GOX) and a net positively charged organophosphorus hydrolase (OPH) were entrapped spontaneously in NH 2 - and HOOC-functionalized mesoporous silica (300 A, FMS) respectively. The specific activity of GOX entrapped in FMS increased with decreasing P LD . With decreasing P LD , I e of GOX in FMS increased from 150%. Unlike GOX, OPH in HOOC-FMS showed increased specific activity with increasing P LD . With increasing P LD , the corresponding I e of OPH in FMS increased from 100% to>200%. A protein structure-based analysis of the protein surface charges directing the electrostatic interaction-based orientation of the protein molecules in FMS demonstrates that substrate access to GOX molecules in FMS is limited at high P LD , consequently lowering the GOX specific activity. In contrast, substrate access to OPH molecules in FMS remains open at high P LD and may promote a more favorable confinement environment that enhances the OPH activity

  15. Effect of fluorozis on the erythrocyte antioxidant enzyme activity levels

    International Nuclear Information System (INIS)

    Akdogan, M.; YiImaz, D.; Yontem, M.; Kalei, S.; Kilic, I.

    2011-01-01

    While the flourine level of (drinking) water was higher than normal ranges in the center of Isparta region before 1995 year, this problematic situation is solved in later years. (However) the individuals who are staying in Yenice district are still expose to high levels of fluorine because of the usage of Andik spring water (3.8 mg/L flour level) as drinking water. In this study we aimed to investigate the harmful effect of floride on human erythrocytes via antioxidant defence system and lipid peroxidation. Therefore, we studied the activities of erythrocyte antioxidant enzymes such as Superoxide Dismutase (SOD), Glutathione Peroxidase (GSH-Px) and Catalase (CAT), and the level of erythrocyte Glutathione (GSH), thiobarbituric acid reactive substance (TBARS) and the level of urine floride in high floride exposed people (children, adult and elderly). The activities of SOD, GSH-Px and CAT and the level of GSH, TBARS and urine floride were higher in 3.8 mg/L floride exposed children (Group II) than 0.8 mg/L floride exposed control children (Group I) (p 0.05). The activities of SOD, GSH-Px and CAT were lower and the levels of TBARS and urine floride were higher in 3.8 mg/L floride exposed elderly people (Group VI) than 0.8 mg/L floride exposed control elderly people (Group V) (p 0.05). As a result we thought that increased SOD, GSH-Px and CAT activities in floride exposed children and adult people, decreased activities of these enzymes in floride exposed elderly people, and increased TBARS in all groups may indicate floride caused oxidative damage in erythrocytes. (author)

  16. Evaluation of the Activities of Antioxidant Enzyme and Lysosomal Enzymes of the Longissimus dorsi Muscle from Hanwoo (Korean Cattle) in Various Freezing Conditions

    OpenAIRE

    Kang, Sun Moon; Kang, Geunho; Seong, Pil-Nam; Park, Beomyoung; Kim, Donghun; Cho, Soohyun

    2014-01-01

    This study was conducted to evaluate the activities of antioxidant enzyme (glutathione peroxidase (GSH-Px)) and lysosomal enzymes (alpha-glucopyranosidase (AGP) and beta-N-acetyl-glucosaminidase (BNAG)) of the longissimus dorsi (LD) muscle from Hanwoo (Korean cattle) in three freezing conditions. Following freezing at -20, -60, and -196? (liquid nitrogen), LD samples (48 h post-slaughter) were treated as follows: 1) freezing for 14 d, 2) 1 to 4 freeze-thaw cycles (2 d of freezing in each cycl...

  17. Horseradish peroxidase-nanoclay hybrid particles of high functional and colloidal stability.

    Science.gov (United States)

    Pavlovic, Marko; Rouster, Paul; Somosi, Zoltan; Szilagyi, Istvan

    2018-08-15

    Highly stable dispersions of enzyme-clay nanohybrids of excellent horseradish peroxidase activity were developed. Layered double hydroxide nanoclay was synthesized and functionalized with heparin polyelectrolyte to immobilize the horseradish peroxidase enzyme. The formation of a saturated heparin layer on the platelets led to charge inversion of the positively charged bare nanoclay and to highly stable aqueous dispersions. Great affinity of the enzyme to the surface modified platelets resulted in strong horseradish peroxidase adsorption through electrostatic and hydrophobic interactions as well as hydrogen bonding network and prevented enzyme leakage from the obtained material. The enzyme kept its functional integrity upon immobilization and showed excellent activity in decomposition of hydrogen peroxide and oxidation of an aromatic compound in the test reactions. In addition, remarkable long term functional stability of the enzyme-nanoclay hybrid was observed making the developed colloidal system a promising antioxidant candidate in biomedical treatments and industrial processes. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Accelerating the peroxidase-like activity of gold nanoclusters at neutral pH for colorimetric detection of heparin and heparinase activity.

    Science.gov (United States)

    Hu, Lianzhe; Liao, Hong; Feng, Lingyan; Wang, Min; Fu, Wensheng

    2018-04-26

    The peroxidase-like catalytic activity of gold nanoclusters (NCs) is quite low around physiological pH, which greatly limits their biological applications. Herein, we found heparin can greatly accelerate the peroxidase-like activity of Au-NCs at neutral pH. The catalytic activity of Au-NCs toward the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) oxidation by H2O2 was 25-fold increased in the presence of heparin at pH 7. The addition of heparin not only accelerated the initial catalytic rate of Au-NCs, but also prevented the Au-NCs from catalyst deactivation. This allows the sensitive colorimetric detection of heparin at neutral pH. In the presence of heparinase, heparin was hydrolyzed into small fragments, weakening the enhancement effect of catalytic activity. Based on this phenomenon, the sensitive colorimetric determination of heparinase in biological samples was also developed.

  19. 5,10,15,20-Tetrakis(4-carboxyl phenyl)porphyrin–CdS nanocomposites with intrinsic peroxidase-like activity for glucose colorimetric detection

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qingyun, E-mail: qyliu@sdust.edu.cn [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Jia, Qingyan; Zhu, Renren; Shao, Qian; Wang, Dongmei; Cui, Peng [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Ge, Jiechao, E-mail: jchge2010@mail.ipc.ac.cn [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-09-01

    Here, we describe the design of a novel mimic peroxidase, nanocomposites composed by 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H{sub 2}TCPP) and cadmium sulfide (CdS). The H{sub 2}TCPP–CdS nanocomposites can catalyze oxidation of substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H{sub 2}O{sub 2} and form a blue product which can be seen by the naked eye in 5 min. The mechanism of the catalytic reaction originated from the generation of hydroxyl radical (·OH), which is a powerful oxidizing agent to oxidize TMB to produce a blue product. Then, we developed a colorimetric method that is highly sensitive and selective to detect glucose, combined with glucose oxidase (GOx). The proposed method allowed the detection of H{sub 2}O{sub 2} concentration in the range of 4 × 10{sup −6}–1.4 × 10{sup −5} M and glucose in the range of 1.875 × 10{sup −5}–1 × 10{sup −4} M with detectable H{sub 2}O{sub 2} concentration as low as 4.6 × 10{sup −7} M and glucose as low as 7.02 × 10{sup −6} M, respectively. The results provided the theoretical basis of practical application in glucose detecting and peroxidase mimetic enzymes. - Graphical abstract: 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H{sub 2}TCPP)–CdS nanohybrids were demonstrated to possess intrinsic peroxidase-like activity and used for a glucose colorimetric sensor. - Highlights: • H{sub 2}TCPP–CdS nanocomposites were synthesized by a facile one step under mild condition. • H{sub 2}TCPP–CdS nanocomposites possess excellent intrinsic peroxidase-like activity. • A sensitive and selective colorimetric sensor for glucose is provided based on H{sub 2}TCPP–CdS nanocomposites. • The generation of hydroxyl radical (·OH) decomposed from H{sub 2}O{sub 2} is contributed to efficient catalytic.

  20. Changes in Peroxidase Activity in the Peel of Unshiub Mandarin (Citrus unshiu Marc.) Fruit with Different Storage Treatments

    OpenAIRE

    Lepeduš, Hrvoje; Jozić, Marko; Štolfa, Ivna; Pavičić, Nikola; Hackenberger, Branimir K.; Cesar, Vera

    2005-01-01

    The Unshiu mandarin (Citrus unshiu Marc.) is the major Citrus crop in Croatia. Limiting factors for longer consumption of Unshiu mandarin are low storage performance and the appearance of chilling injuries during storage. Previous studies indicated that oxidative stress might be involved in cold-induced peel damage of harvested Citrus fruit. The aim of the present study was to investigate peroxidase distribution, isoenzyme pattern and activity in the peel of Unshiu mandarin fruit. Special goa...

  1. Changes of enzyme activities in lens after glaucoma trabecular resection

    Directory of Open Access Journals (Sweden)

    Jian-Ping Wang

    2013-08-01

    Full Text Available AIM: To observe the change of lens antioxidant enzyme activity after glaucoma trabecular resection. METHODS: Thirty-two eyes of sixteen New-Zealand rabbits(2.2-2.4kgwere divided into two groups. The left eyes of rabbits underwent standard glaucoma trabecular resection were treatment group, and the normal right eyes served as controls. Transparency of lenses was monitored by a slit-lamp biomicroscopy before and after glaucoma trabecular resection. The morphology of lens cells was observed under the light microscope.The activities of Na+-K+-ATPase,catalase(CAT, glutathion peroxidase(GSH-px, glutathione reductase(GR, superoxide dismutase(SODand content of malondialdehyde(MDAin lenses were detected six months after trabecular resection. RESULTS: Lenses were clear in both treatment group and normal control group during the six months after operation. The morphology and structure of lens cells were normal under the light microscope in both operation group and normal group. The activity of lens cells antioxidant enzyme activity were significantly decreased in operation group compared with control group, Na+-K+-ATPase declined by 20.97%, CAT declined by 16.36%, SOD declined by 4.46%, GR declined by 4.85%, GSH-px declined by 10.02%, and MDA increased by 16.31%. CONCLUSION: Glaucoma trabecular resection can induce the change of Na+-K+-ATPase, CAT, GSH-px, GR, SOD and MDA in lens of rabbit. Glaucoma filtration surgery for the occurrence of cataract development mechanism has important guiding significance.

  2. Synthesis and Evaluation of Amyloid β Derived and Amyloid β Independent Enhancers of the Peroxidase-like Activity of Heme.

    Science.gov (United States)

    Wißbrock, Amelie; Kühl, Toni; Silbermann, Katja; Becker, Albert J; Ohlenschläger, Oliver; Imhof, Diana

    2017-01-12

    Labile heme has been suggested to have an impact in several severe diseases. In the context of Alzheimer's disease (AD), however, decreased levels of free heme have been reported. Therefore, we were looking for an assay system that can be used for heme concentration determination. From a biochemical point of view the peroxidase activity of the Aβ-heme complex seemed quite attractive to pursue this goal. As a consequence, a peptide that is able to increase the readout even in the case of a low heme concentration is favorable. The examination of Aβ- and non-Aβ-derived peptides in complex with heme revealed that the peroxidase-like activity significantly depends on the peptide sequence and length. A 23mer His-based peptide derived from human fatty acyl-CoA reductase 1 in complex with heme exhibited a significantly higher peroxidase activity than Aβ(40)-heme. Structural modeling of both complexes demonstrated that heme binding via a histidine can be supported by hydrogen bond interactions of a basic residue near the propionate carboxyl function of protoporphyrin IX. Furthermore, the interplay of Aβ-heme and the lipoprotein LDL as a potential physiological effector of Aβ was examined.

  3. Colorimetric assay of copper ions based on the inhibition of peroxidase-like activity of MoS2 nanosheets

    Science.gov (United States)

    Chen, Huan; Li, Zhihong; Liu, Xueting; Zhong, Jianhai; Lin, Tianran; Guo, Liangqia; Fu, Fengfu

    2017-10-01

    The peroxidase-like catalytic activity of MoS2 nanomaterials has been utilized for colorimetric bioassays and medical diagnostics. However, the application of peroxidase-like catalytic activity of MoS2 nanomaterials in environmental analysis was seldom explored. Herein, copper ions were found to inhibit the peroxidase-like catalytic activity of MoS2 nanosheets, which can catalyze the oxidation of 3, 3‧, 5, 5‧-tetramethylbenzidine by H2O2 to produce a colorimetric product. Based on this finding, a simple sensitive colorimetric method for the detection of copper ions was developed. In the presence of copper ions, the absorbance and color of the solution decreased with the increasing concentration of copper ions. The color of the solution can be used to semi-quantitative on-site assay of copper ions by naked eyes. A linear relationship between the absorbance and the concentration of copper ions was observed in the range of 0.4-4.0 μmol L- 1 with a detection limit of 92 nmol L- 1, which was much lower than the maximum contaminant level of copper in drinking water legislated by the Environmental Protection Agency of USA and the World Health Organization. The method was applied to detect copper ions in environmental water samples with satisfactory results.

  4. Tetra(p-tolyl)borate-functionalized solvent polymeric membrane: a facile and sensitive sensing platform for peroxidase and peroxidase mimetics.

    Science.gov (United States)

    Wang, Xuewei; Qin, Wei

    2013-07-22

    The determination of peroxidase activities is the basis for enzyme-labeled bioaffinity assays, peroxidase-mimicking DNAzymes- and nanoparticles-based assays, and characterization of the catalytic functions of peroxidase mimetics. Here, a facile, sensitive, and cost-effective solvent polymeric membrane-based peroxidase detection platform is described that utilizes reaction intermediates with different pKa values from those of substrates and final products. Several key but long-debated intermediates in the peroxidative oxidation of o-phenylenediamine (o-PD) have been identified and their charge states have been estimated. By using a solvent polymeric membrane functionalized by an appropriate substituted tetraphenylborate as a receptor, those cationic intermediates could be transferred into the membrane from the aqueous phase to induce a large cationic potential response. Thus, the potentiometric indication of the o-PD oxidation catalyzed by peroxidase or its mimetics can be fulfilled. Horseradish peroxidase has been detected with a detection limit at least two orders of magnitude lower than those obtained by spectrophotometric techniques and traditional membrane-based methods. As an example of peroxidase mimetics, G-quadruplex DNAzymes were probed by the intermediate-sensitive membrane and a label-free thrombin detection protocol was developed based on the catalytic activity of the thrombin-binding G-quadruplex aptamer. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Controlled immobilisation of active enzymes on the cowpea mosaic virus capsid

    Science.gov (United States)

    Aljabali, Alaa A. A.; Barclay, J. Elaine; Steinmetz, Nicole F.; Lomonossoff, George P.; Evans, David J.

    2012-08-01

    Immobilisation of horseradish peroxidase (HRP) and glucose oxidase (GOX) via covalent attachment of modified enzyme carbohydrate to the exterior of the cowpea mosaic virus (CPMV) capsid gave high retention of enzymatic activity. The number of enzymes bound per virus was determined to be about eleven for HRP and 2-3 for GOX. This illustrates that relatively large biomacromolecules can be readily coupled to the virus surface using simple conjugation strategies. Virus-biomacromolecule hybrids have great potential for uses in catalysis, diagnostic assays or biosensors.Immobilisation of horseradish peroxidase (HRP) and glucose oxidase (GOX) via covalent attachment of modified enzyme carbohydrate to the exterior of the cowpea mosaic virus (CPMV) capsid gave high retention of enzymatic activity. The number of enzymes bound per virus was determined to be about eleven for HRP and 2-3 for GOX. This illustrates that relatively large biomacromolecules can be readily coupled to the virus surface using simple conjugation strategies. Virus-biomacromolecule hybrids have great potential for uses in catalysis, diagnostic assays or biosensors. Electronic supplementary information (ESI) available: Alternative conjugation strategies, agarose gel electrophoresis of CPMV and CPMV-HRP conjugates, UV-vis spectrum of HRP-ADHCPMV, agarose gel electrophoresis of GOX-ADHCPMV particles and corresponding TEM image, calibration curves for HRP-ADHCPMV and GOX-ADHCPMV, DLS data for GOX-ADHCPMV are made available. See DOI: 10.1039/c2nr31485a

  6. Proteomic and activity profiles of ascorbate-glutathione cycle enzymes in germinating barley embryo

    DEFF Research Database (Denmark)

    Bønsager, Birgit Christine; Shahpiri, Azar; Finnie, Christine

    2010-01-01

    Enzymes involved in redox control are important during seed germination and seedling growth. Ascorbate-glutathione cycle enzymes in barley embryo extracts were monitored both by 2D-gel electrophoresis and activity measurements from 4 to 144 h post imbibition (PI). Strikingly different activity...... profiles were observed. No ascorbate peroxidase (APX) activity was present in mature seeds but activity was detected after 24 h PI and increased 14-fold up to 144 h PI. In contrast, dehydroascorbate reductase (DHAR) activity was present at 4 h PI and first decreased by 9-fold until 72 h PI followed by a 5......-fold increase at 144 h PI. Glutathione reductase and monodehydroascorbate reductase activities were also detected at 4 h PI, and showed modest increases of 1.8- and 2.7-fold, respectively, by 144 h PI. The combination of functional analysis with the proteomics approach enabled correlation...

  7. Enzyme activity of a Phanerochaete chrysosporium cellobiohydrolase

    African Journals Online (AJOL)

    The aim of this study was to produce a secreted, heterologously expressed Phanerochaete chrysosporium cellobiohydrolase (CBHI.1) protein that required no in vitro chemical refolding and to investigate the cellulolytic activity of the clone expressing the glutathione S-transferase (GST) fused CBHI.1 protein. Plate enzyme ...

  8. Purification and characterization of a novel anti-HSV-2 protein with antiproliferative and peroxidase activities from Stellaria media

    Institute of Scientific and Technical Information of China (English)

    Yu Shan; Yuhong Zheng; Fuqin Guan; Jianjian Zhou; Haiguang Zhao; Bing Xia; Xu Feng

    2013-01-01

    A novel antiviral protein,designated as Stellarmedin A,was purified from Stellaria media (L.) Vill.(Caryophyllaceae) by using ammonium sulfate precipitation,cation-exchange chromatography system.Gel electrophoresis analysis showed that Stellarmedin A is a highly basic glycoprotein with a molecular weight of 35.1 kDa and an isoelectric point of ~8.7.The Nterminal 14-amino acid sequence,MGNTGVLTGERNDR,is similar to those of other plant peroxidases.This protein inhibited herpes simplex virus type 2 (HSV-2) replication in vitro with an ICso of 13.18 μg/ml and a therapeutic index exceeding 75.9.It was demonstrated that Stellarmedin A affects the initial stage of HSV-2 infection and is able to inhibit the proliferation of promyelocytic leukemia HL-60 and colon carcinoma LoVo cells with an ICso of 9.09 and 12.32 μM,respectively.Moreover,Stellarmedin A has a peroxidase activity of 36.6 μmol/min/mg protein,when gualacol was used as substrate.To our knowledge,this is the first report about an anti-HSV-2 protein with antiproliferative and peroxidase activities from S.media.

  9. Effect of sprint cycle training on activities of antioxidant enzymes in human skeletal muscle

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Apple, F. S.; Sjödin, B.

    1996-01-01

    (P anaerobic capacity in the trained muscle. The present study demonstrates that intermittent sprint cycle training that induces an enhanced capacity for anaerobic energy generation also improves......The effect of intermittent sprint cycle training on the level of muscle antioxidant enzyme protection was investigated. Resting muscle biopsies, obtained before and after 6 wk of training and 3, 24, and 72 h after the final session of an additional 1 wk of more frequent training, were analyzed...... for activities of the antioxidant enzymes glutathione peroxidase (GPX), glutathione reductase (GR), and superoxide dismutase (SOD). Activities of several muscle metabolic enzymes were determined to assess the effectiveness of the training. After the first 6-wk training period, no change in GPX, GR, or SOD...

  10. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Science.gov (United States)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  11. Survival of Bemisia tabaci and activity of plant defense-related enzymes in genotypes of Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Luis Latournerie-Moreno

    2015-03-01

    Full Text Available The whitefly Bemisia tabaci (Gennadius, 1889 is a major plant pest of horticultural crops from the families Solanaceae, Fabaceae and Cucurbitaceae in Neotropical areas. The exploration of host plant resistance and their biochemical mechanisms offers an excellent alternative to better understand factors affecting the interaction between phytophagous insect and host plant. We evaluated the survival of B. tabaci in landrace genotypes of Capsicum annuum L., and the activity of plant defense-related enzymes (chitinase, polyphenoloxidase, and peroxidase. The landrace genotypes Amaxito, Tabaquero, and Simojovel showed resistance to B. tabaci, as we observed more than 50% nymphal mortality, while in the commercial susceptible genotype Jalapeño mortality of B. tabaci nymphs was not higher than 20%. The activities of plant defense-related enzymes were significantly different among pepper genotypes (P < 0.05. Basal activities of chitinase, polyphenoloxidase and peroxidase were significantly lower or equal in landrace genotypes than that of the commercial genotype Jalapeño. The activity of plant enzymes was differential among pepper genotypes (P < 0.05. For example, the activity of chitinase enzyme generally was higher in non-infested plants with B. tabaci than those infested. Instead polyphenoloxidase ('Amaxito' and 'Simojovel' and peroxidase enzymes activities ('Tabaquero' increased in infested plants (P < 0.05. We conclude that basal activities of plant defense-related enzymes could be act through other mechanism plant induction, since plant defense-related enzymes showed a different induction response to B. tabaci. We underlined the role of polyphenoloxidase as plant defense in the pepper genotype Simojovel related to B. tabaci.

  12. Tailoring Enzyme-Like Activities of Gold Nanoclusters by Polymeric Tertiary Amines for Protecting Neurons Against Oxidative Stress.

    Science.gov (United States)

    Liu, Ching-Ping; Wu, Te-Haw; Lin, Yu-Lung; Liu, Chia-Yeh; Wang, Sabrina; Lin, Shu-Yi

    2016-08-01

    The cytotoxicity of nanozymes has drawn much attention recently because their peroxidase-like activity can decompose hydrogen peroxide (H2 O2 ) to produce highly toxic hydroxyl radicals (•OH) under acidic conditions. Although catalytic activities of nanozymes are highly associated with their surface properties, little is known about the mechanism underlying the surface coating-mediated enzyme-like activities. Herein, it is reported for the first time that amine-terminated PAMAM dendrimer-entrapped gold nanoclusters (AuNCs-NH2 ) unexpectedly lose their peroxidase-like activity while still retaining their catalase-like activity in physiological conditions. Surprisingly, the methylated form of AuNCs-NH2 (i.e., MAuNCs-N(+) R3 , where R = H or CH3 ) results in a dramatic recovery of the intrinsic peroxidase-like activity while blocking most primary and tertiary amines (1°- and 3°-amines) of dendrimers to form quaternary ammonium ions (4°-amines). However, the hidden peroxidase-like activity is also found in hydroxyl-terminated dendrimer-encapsulated AuNCs (AuNCs-OH, inside backbone with 3°-amines), indicating that 3°-amines are dominant in mediating the peroxidase-like activity. The possible mechanism is further confirmed that the enrichment of polymeric 3°-amines on the surface of dendrimer-encapsulated AuNCs provides sufficient suppression of the critical mediator •OH for the peroxidase-like activity. Finally, it is demonstrated that AuNCs-NH2 with diminished cytotoxicity have great potential for use in primary neuronal protection against oxidative damage. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Arabinogalactan proteins: focus on carbohydrate active enzymes

    Directory of Open Access Journals (Sweden)

    Eva eKnoch

    2014-06-01

    Full Text Available Arabinogalactan proteins (AGPs are a highly diverse class of cell surface proteoglycans that are commonly found in most plant species. AGPs play important roles in many cellular processes during plant development, such as reproduction, cell proliferation, pattern formation and growth, and in plant-microbe interaction. However, little is known about the molecular mechanisms of their function. Numerous studies using monoclonal antibodies that recognize different AGP glycan epitopes have shown the appearance of a slightly altered AGP glycan in a specific stage of development in plant cells. Therefore, it is anticipated that the biosynthesis and degradation of AGP glycan is tightly regulated during development. Until recently, however, little was known about the enzymes involved in the metabolism of AGP glycans. In this review, we summarize recent discoveries of carbohydrate active enzymes (CAZy; http://www.cazy.org/ involved in the biosynthesis and degradation of AGP glycans, and we discuss the biological role of these enzymes in plant development.

  14. Structure of soybean seed coat peroxidase: a plant peroxidase with unusual stability and haem-apoprotein interactions

    DEFF Research Database (Denmark)

    Henriksen, A; Mirza, O; Indiani, C

    2001-01-01

    Soybean seed coat peroxidase (SBP) is a peroxidase with extraordinary stability and catalytic properties. It belongs to the family of class III plant peroxidases that can oxidize a wide variety of organic and inorganic substrates using hydrogen peroxide. Because the plant enzyme is a heterogeneous...... glycoprotein, SBP was produced recombinant in Escherichia coli for the present crystallographic study. The three-dimensional structure of SBP shows a bound tris(hydroxymethyl)aminomethane molecule (TRIS). This TRIS molecule has hydrogen bonds to active site residues corresponding to the residues that interact...... with the small phenolic substrate ferulic acid in the horseradish peroxidase C (HRPC):ferulic acid complex. TRIS is positioned in what has been described as a secondary substrate-binding site in HRPC, and the structure of the SBP:TRIS complex indicates that this secondary substrate-binding site could...

  15. Concentration profiles near an activated enzyme.

    Science.gov (United States)

    Park, Soohyung; Agmon, Noam

    2008-09-25

    When a resting enzyme is activated, substrate concentration profile evolves in its vicinity, ultimately tending to steady state. We use modern theories for many-body effects on diffusion-influenced reactions to derive approximate analytical expressions for the steady-state profile and the Laplace transform of the transient concentration profiles. These show excellent agreement with accurate many-particle Brownian-dynamics simulations for the Michaelis-Menten kinetics. The steady-state profile has a hyperbolic dependence on the distance of the substrate from the enzyme, albeit with a prefactor containing the complexity of the many-body effects. These are most conspicuous for the substrate concentration at the surface of the enzyme. It shows an interesting transition as a function of the enzyme turnover rate. When it is high, the contact concentration decays monotonically to steady state. However, for slow turnover it is nonmonotonic, showing a minimum due to reversible substrate binding, then a maximum due to diffusion of new substrate toward the enzyme, and finally decay to steady state. Under certain conditions one can obtain a good estimate for the critical value of the turnover rate constant at the transition.

  16. Activity of the ligninolytic enzymes of the Phanerochaete chrysosporium and its variation with the Mn+2 addition

    International Nuclear Information System (INIS)

    Jimenez T, Gloria Alicia; Mejia G, Amanda I; Lopez O, Betty Lucy

    1999-01-01

    The activity of the ligninolytic enzymes, lignin peroxidase (LiP), manganese peroxidase (MnP) and Laccase, in submerged cultures of Phanerochaete chrysosporium, with limited amounts of carbon and nitrogen, were affected by the addition of Mn+2. In cultures with o and 1,25 ppm of Mn+2, only the lip was detected and its higher activity level was observed in the cultures with 1.25 ppm of Mn+2. The cultures with 40 ppm of Mn+2 showed activities of lip, MnP and Laccase. The presence of the three enzymes in the same culture had not been reported and it is of great importance because is shows that the fungus and its lignolitic machinery can act sequentially

  17. Changes of Soil Enzyme Activities in Different Restoration Ages of Spruce Forests on the Eastern Qinghai-Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-mei; BAO Wei-kai; PANG Xue-yong; WU Ning; ZHOU Guo-yi

    2005-01-01

    Six soil enzymes (invertase, acid phosphatase, proteinase, catalase, peroxidase and polyphenoloxidase ) were chosen for investigation under different spruce forests with restoration ages of 4,10,16 years and an old-growth spruce forest over 400 years old in the eastern Qinghai-Tibet Plateau, China. Results showed that the activities of invertase, phosphatase, proteinase, catalase and peroxidase decreased in newly restored forests except for pholyphenoloxidase. With the development of forests after restoration, the activities of invertase, acid phosphadase, proteinase increased gradually. Our study also indicated that the soil enzyme activities were associated with surface soils and decreased with depths. This result suggested that in the earlier restoration stage the application of organic fertilizer may be more effective by surface addition to soils than deep addition.

  18. Seasonal changes of peroxidase and catalase activities in leaves of several arborescent species subject to different industrial air pollutions in Upper Silesia

    Energy Technology Data Exchange (ETDEWEB)

    Raczek, E.; Stolarek, J.

    1979-01-01

    Year-round investigations of seasonal patterns of peroxidase and catalase activities in leaves of several deciduous and coniferous arborescent species in forests of Upper Silesia subjected to various amounts of industrial gases and dusts were carried out. The samples of leaves of Betula verrucosa EHRH, Quercus robur L., Q. rubra L., Pinus nigra ARNOLD, and P. silvestris L. were collected at different distances from an iron smelting plant. It was found that raising level of the pollution enhances peroxidase activity in leaves and needles. The induction of peroxidase activity by pollutants exhibited seasonal changes specific for the species and was subjected to the effect of temperature of the environment and was also related to the natural resistivity of a given species. In contrast to peroxidase, the patterns of catalase activity changes did not appear to be specifically influenced by industrial air pollutants. 22 references, 5 figures, 4 tables.

  19. Antioxidant enzymes activities in obese Tunisian children

    Directory of Open Access Journals (Sweden)

    Sfar Sonia

    2013-01-01

    Full Text Available Abstract Background The oxidant stress, expected to increase in obese adults, has an important role in the pathogenesis of many diseases. It results when free radical formation is greatly increased or protective antioxidant mechanisms are compromised. The main objective of this study is to evaluate the antioxidant response to obesity-related stress in healthy children. Methods A hundred and six healthy children (54 obese and 52 controls, aged 6–12 years old, participated in this study. The collected data included anthropometric measures, blood pressure, fasting glucose, total cholesterol, triglycerides and enzymatic antioxidants (Superoxide dismutase: SOD, Catalase: CAT and Glutathione peroxidase: GPx. Results The first step antioxidant response, estimated by the SOD activity, was significantly higher in obese children compared with normal-weight controls (p  Conclusions The obesity-related increase of the oxidant stress can be observed even in the childhood period. In addition to the complications of an increased BMI, obesity itself can be considered as an independent risk factor of free radical production resulting in an increased antioxidant response.

  20. Acute Exercise Increases Plasma Total Antioxidant Status and Antioxidant Enzyme Activities in Untrained Men

    Directory of Open Access Journals (Sweden)

    C. Berzosa

    2011-01-01

    Full Text Available Antioxidant defences are essential for cellular redox regulation. Since free-radical production may be enhanced by physical activity, herein, we evaluated the effect of acute exercise on total antioxidant status (TAS and the plasma activities of catalase, glutathione reductase, glutathione peroxidase, and superoxide dismutase and its possible relation to oxidative stress resulting from exercise. Healthy untrained male subjects (=34 performed three cycloergometric tests, including maximal and submaximal episodes. Venous blood samples were collected before and immediately after each different exercise. TAS and enzyme activities were assessed by spectrophotometry. An increase of the antioxidant enzyme activities in plasma was detected after both maximal and submaximal exercise periods. Moreover, under our experimental conditions, exercise also led to an augmentation of TAS levels. These findings are consistent with the idea that acute exercise may play a beneficial role because of its ability to increase antioxidant defense mechanisms through a redox sensitive pathway.

  1. Purification, characterization and stability of barley grain peroxidase BP1, a new type of plant peroxidase

    DEFF Research Database (Denmark)

    Rasmussen, Christine B; Henriksen, Anette; Abelskov, A. Katrine

    1997-01-01

    peroxidase isoenzyme C (HRP C). However, when measuring the specific activity of BP 1 at pH 4.0 in the presence of 1 mM CaCl2, the enzyme was as competent as HRP C at neutral pH towards a variety of substrates (mM mg(-1) min(-1)): coniferyl alcohol (930+/-48), caffeic acid (795+/-53), ABTS (2,2(1)-azino...

  2. Analysis of monoamine oxidase (MAO) enzymatic activity by high-performance liquid chromatography-diode array detection combined with an assay of oxidation with a peroxidase and its application to MAO inhibitors from foods and plants.

    Science.gov (United States)

    Herraiz, Tomás; Flores, Andrea; Fernández, Lidia

    2018-01-15

    Monoamine oxidase (MAO) enzymes catalyze the oxidative deamination of biogenic amines and neurotransmitters and produce ammonia, aldehydes, and hydrogen peroxide which is involved in oxidative processes. Inhibitors of MAO-A and -B isozymes are useful as antidepressants and neuroprotectants. The assays of MAO usually measure amine oxidation products or hydrogen peroxide by spectrophotometric techniques. Those assays are often compromised by interfering compounds resulting in poor results. This research describes a new method that combines in the same assay the oxidative deamination of kynuramine to 4-hydroxyquinoline analyzed by HPLC-DAD with the oxidation of tetramethylbenzidine (TMB) (or Amplex Rex) by horseradish peroxidase (HRP) in presence of hydrogen peroxide. The new method was applied to study the inhibition of human MAO-A and -B by bioactive compounds including β-carboline alkaloids and flavonoids occurring in foods and plants. As determined by HPLC-DAD, β-carbolines, methylene blue, kaempferol and clorgyline inhibited MAO-A and methylene blue, 5-nitroindazole, norharman and deprenyl inhibited MAO-B, and all of them inhibited the oxidation of TMB in the same extent. The flavonoids catechin and cyanidin were not inhibitors of MAO by HPLC-DAD but highly inhibited the oxidation of TMB (or Amplex Red) by peroxidase whereas quercetin and resveratrol were moderate inhibitors of MAO-A by HPLC-DAD, but inhibited the peroxidase assay in a higher level. For some phenolic compounds, using the peroxidase-coupled assay to measure MAO activity led to mistaken results. The new method permits to discern between true inhibitors of MAO from those that are antioxidants and which interfere with peroxidase assays but do not inhibit MAO. For true inhibitors of MAO, inhibition as determined by HPLC-DAD correlated well with inhibition of the oxidation of TMB and this approach can be used to assess the in vitro antioxidant activity (less hydrogen peroxide production) resulting

  3. Quantitative enzyme activity determination with zeptomole sensitivity by microfluidic gradient-gel zymography.

    Science.gov (United States)

    Hughes, Alex J; Herr, Amy E

    2010-05-01

    We describe a sensitive zymography technique that utilizes an automated microfluidic platform to report enzyme molecular weight, amount, and activity (including k(cat) and K(m)) from dilute protein mixtures. Calf intestinal alkaline phosphatase (CIP) is examined in detail as a model enzyme system, and the method is also demonstrated for horseradish peroxidase (HRP). The 40 min assay has a detection limit of 5 zmol ( approximately 3 000 molecules) of CIP. Two-step pore-limit electrophoresis with enzyme assay (PLENZ) is conducted in a single, straight microchannel housing a polyacrylamide (PA) pore-size gradient gel. In the first step, pore limit electrophoresis (PLE) sizes and pseudoimmobilizes resolved proteins. In the second step, electrophoresis transports both charged and neutral substrates into the PLE channel to the entrapped proteins. Arrival of substrate at the resolved enzyme band generates fluorescent product that reveals enzyme molecular weight against a fluorescent protein ladder. Additionally, the PLENZ zymography assay reports the kinetic properties of CIP in a fully quantitative manner. In contrast to covalent enzyme immobilization, physical pseudoimmobilization of CIP in the PA gel does not significantly reduce its maximum substrate turnover rate. However, an 11-fold increase in the Michaelis constant (over the free solution value) is observed, consistent with diffusional limitations on substrate access to the enzyme active site. PLENZ offers a robust platform for rapid and multiplexed functional analysis of heterogeneous protein samples in drug discovery, clinical diagnostics, and biocatalyst engineering.

  4. Regulation of antioxidant enzyme activities in male and female rat macrophages by sex steroids

    Directory of Open Access Journals (Sweden)

    Azevedo R.B.

    2001-01-01

    Full Text Available Human and animal immune functions present sex dimorphism that seems to be mainly regulated by sex hormones. In the present study, the activities of the antioxidant enzymes total superoxide dismutase (SOD, catalase (CAT, and glutathione peroxidase (GSH-Px were measured in intraperitoneal resident macrophages from adult male and female rats. In addition to comparing males and females, we also examined the regulation of these enzyme activities in macrophages by sex steroids. GSH-Px activity did not differ between male and female macrophages. However, both total SOD and CAT activities were markedly higher in females than in males (83 and 180%. Removal of the gonads in both males and females (comparison between castrated groups increased the difference in SOD activity from 83 to 138% and reduced the difference in CAT activity from 180 to 86%. Castration and testosterone administration did not significantly modify the activities of the antioxidant enzymes in male macrophages. Ovariectomy did not affect SOD or GSH-Px activity but markedly reduced (48% CAT activity. This latter change was fully reversed by estrogen administration, whereas progesterone had a smaller effect. These results led us to conclude that differences in the SOD and CAT activities may partially explain some of the differences in immune function reported for males and females. Also, estrogen is a potent regulator of CAT in macrophages and therefore this enzyme activity in macrophages may vary considerably during the menstrual cycle.

  5. Enzyme Activities in Waste Water and Activated Sludge

    DEFF Research Database (Denmark)

    Nybroe, Ole; Jørgensen, Per Elberg; Henze, Mogens

    1992-01-01

    The purpose of the present study was to evaluate the potential of selected enzyme activity assays to determine microbial abundance and heterotrophic activity in waste water and activated sludge. In waste water, esterase and dehydrogenase activities were found to correlate with microbial abundance...... measured as colony forming units of heterotrophic bacteria. A panel of four enzyme activity assays, α-glucosidase, alanine-aminopeptidase, esterase and dehydrogenase were used to characterize activated sludge and anaerobic hydrolysis sludge from a pilot scale plant. The enzymatic activity profiles were...... distinctly different, suggesting that microbial populations were different, or had different physiological properties, in the two types of sludge. Enzyme activity profiles in activated sludge from four full-scale plants seemed to be highly influenced by the composition of the inlet. Addition of hydrolysed...

  6. Hydrolytic enzyme activity enhanced by Barium supplementation

    Directory of Open Access Journals (Sweden)

    Camilo Muñoz

    2016-10-01

    Full Text Available Hydrolysis of polymers is a first and often limiting step during the degradation of plant residues. Plant biomass is generally a major component of waste residues and a major renewable resource to obtain a variety of secondary products including biofuels. Improving the performance of enzymatic hydrolysis of plant material with minimum costs and limiting the use of additional microbial biomass or hydrolytic enzymes directly influences competitiveness of these green biotechnological processes. In this study, we cloned and expressed a cellulase and two esterases recovered from environmental thermophilic soil bacterial communities and characterize their optimum activity conditions including the effect of several metal ions. Results showed that supplementing these hydrolytic reactions with Barium increases the activity of these extracellular hydrolytic enzymes. This observation represents a simple but major improvement to enhance the efficiency and competitiveness of this process within an increasingly important biotechnological sector.

  7. Erythrocyte superoxide dismutase, glutathione peroxidase, and catalase activities and risk of coronary heart disease in generally healthy women: a prospective study.

    Science.gov (United States)

    Yang, Shuman; Jensen, Majken K; Rimm, Eric B; Willett, Walter; Wu, Tianying

    2014-11-01

    Erythrocyte antioxidant enzymes are major circulating antioxidant enzymes in the oxidative stress defense system. Few prospective studies have assessed the association between these enzymes and the risk of coronary heart disease (CHD) in generally healthy adults. We conducted a prospective nested case-control study of CHD among 32,826 women at baseline with 15 years of follow-up from 1989 to 2004 in the Nurses' Health Study. We investigated the association of baseline erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities with the risk of CHD. A total of 365 cases and 728 controls were included in the analysis. Overall, the relative risks of CHD associated with 1-standard deviation higher SOD, GPx, and CAT activities were 1.07 (95% confidence interval (CI): 0.94, 1.22), 1.04 (95% CI: 0.91, 1.18), and 1.04 (95% CI: 0.92, 1.17), respectively. Multivariable adjustments did not change the associations appreciably. Fasting status did not modify the associations, with the exception that SOD activity was positively associated with the risk of CHD among participants who provided blood samples within 12 hours of fasting. Overall, activities of SOD, GPx, and CAT were not associated with CHD among women who were generally healthy at the time of blood collection. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. One of the possible mechanisms for the inhibition effect of Tb(III) on peroxidase activity in horseradish (Armoracia rusticana) treated with Tb(III).

    Science.gov (United States)

    Guo, Shaofen; Cao, Rui; Lu, Aihua; Zhou, Qing; Lu, Tianhong; Ding, Xiaolan; Li, Chaojun; Huang, Xiaohua

    2008-05-01

    One of the possible mechanisms for the inhibition effect of Tb(III) on peroxidase activity in horseradish (Armoracia rusticana) treated with Tb(III) was investigated using some biophysical and biochemical methods. Firstly, it was found that a large amount of Tb(III) can be distributed on the cell wall, that some Tb(III) can enter into the horseradish cell, indicating that peroxidase was mainly distributed on cell wall, and thus that Tb(III) would interact with horseradish peroxidase (HRP) in the plant. In addition, peroxidase bioactivity was decreased in the presence of Tb(III). Secondly, a new peroxidase-containing Tb(III) complex (Tb-HRP) was obtained from horseradish after treatment with Tb(III); the molecular mass of Tb-HRP is near 44 kDa and the pI is about 8.80. Thirdly, the electrocatalytic activity of Tb-HRP is much lower than that of HRP obtained from horseradish without treatment with Tb(III). The decrease in the activity of Tb-HRP is due to the destruction (unfolding) of the conformation in Tb-HRP. The planarity of the heme active center in the Tb-HRP molecule was increased and the extent of exposure of Fe(III) in heme was decreased, leading to inhibition of the electron transfer. The microstructure change in Tb-HRP might be the result of the inhibition effect of Tb(III) on peroxidase activity in horseradish.

  9. Investigation of glutathione peroxidase activity in chicken meat under different experimental conditions Investigação da atividade de glutationa peroxidase em carne de frango submetida a diferentes condições experimentais

    Directory of Open Access Journals (Sweden)

    Alexandre José Cichoski

    2012-12-01

    Full Text Available Due to the fact that previous studies on the enzymatic activity of Glutathione peroxidase (GSH-Px diverge widely in their methodology and results, this study aimed to investigate the influence of different analytical conditions on GSH-Px activity in chicken thighs from broilers that were fed different diets with different sources and concentrations of selenium. GSH-Px activity was evaluated six hours after slaughter and 120 days after frozen storage at -18 ºC. The different analytical conditions included time of pre-incubation (0, 10 and 30 minutes, reaction medium, types of substrate (H2O2 (0.72 mM, 7.2 mM, and 72 mM and Terc-butil hydroperoxide 15 mM, and different buffer concentrations (buffer 1, potassium phosphate 50 mM pH 7.0 + EDTA 1 mM + mercaptoethanol 1 mM, and buffer 2, tris-HCl 50 mM pH 7.6 + EDTA 1 mM + mercapthanol 5 mM. The results show that the highest GSH-Px activity was observed when enzyme and substrate were in contact at 22 ºC without any pre-incubation, and that, when used at concentrations above 0.72 mM, hydrogen peroxide saturated the GSH-Px enzyme and inhibited its activity. The enzyme presented higher affinity to hydrogen peroxide when compared to terc-butil peroxide, and the addition of a buffer containing mercaptoethanol did not increase GSH-Px enzymatic activity. The activity of GSH-Px was not influenced by the source and concentration of selenium in the diet either. The obtained results allowed the determination of the best temperature of contact between the enzyme and substrate (22 ºC, the optimum concentration, and the type of substrate and buffer to be used. This information is extremely useful for future studies on GSH-Px activity in meat due to the divergence and little information found in the literature.Uma vez que estudos anteriores sobre a atividade enzimática da glutationa peroxidase (GSH-Px divergem acerca da metodologia e dos resultados, este estudo teve por objetivo investigar a influência de

  10. Hydrolytic and ligninolytic enzyme activities in the Pb contaminated soil inoculated with litter-decomposing fungi.

    Science.gov (United States)

    Kähkönen, Mika A; Lankinen, Pauliina; Hatakka, Annele

    2008-06-01

    The impact of Pb contamination was tested to five hydrolytic (beta-glucosidase, beta-xylosidase, beta-cellobiosidase, alpha-glucosidase and sulphatase) and two ligninolytic (manganese peroxidase, MnP and laccase) enzyme activities in the humus layer in the forest soil. The ability of eight selected litter-degrading fungi to grow and produce extracellular enzymes in the heavily Pb (40 g Pb of kg ww soil(-1)) contaminated and non-contaminated soil in the non-sterile conditions was also studied. The Pb content in the test soil was close to that of the shooting range at Hälvälä (37 g Pb of kg ww soil(-1)) in Southern Finland. The fungi were Agaricus bisporus, Agrocybe praecox, Gymnopus peronatus, Gymnopilus sapineus, Mycena galericulata, Gymnopilus luteofolius, Stropharia aeruginosa and Stropharia rugosoannulata. The Pb contamination (40 g Pb of kg ww soil(-1)) was deleterious to all five studied hydrolytic enzyme activities after five weeks of incubation. All five hydrolytic enzyme activities were significantly higher in the soil than in the extract of the soil indicating that a considerable part of enzymes were particle bound in the soils. Hydrolytic enzyme activities were higher in the non-contaminated soil than in the Pb contaminated soil. Fungal inocula increased the hydrolytic enzyme activities beta-cellobiosidase and beta-glucosidase in non-contaminated soils. All five hydrolytic enzyme activities were similar with fungi and without fungi in the Pb contaminated soil. This was in line that Pb contamination (40 g Pb of kg ww soil(-1)) depressed the growth of all fungi compared to those grown without Pb in the soil. Laccase and MnP activities were low in both Pb contaminated and non-contaminated soil cultures. MnP activities were higher in soil cultures containing Pb than without Pb. Our results showed that Pb in the shooting ranges decreased fungal growth and microbial functioning in the soil.

  11. Comparative study on the peroxidase activity from the floats of Caulerpa lentillifera (grapes seaweeds), roots of Tamarindus indica (tamarind), Eichhornia crassipes (water hyacinth) and Dracaena surculosa (spotted dracaena)

    International Nuclear Information System (INIS)

    Berosil, Maan Dyann N.; Magtibay, Cherrie Joy C.

    2005-02-01

    Peroxidase activities from four different varieties of plant roots were investigated through the use of UV-Vis spectrophotometer. Hydrogen peroxide was used as the substrate and phosphate buffer at a pH that have been determined to be the optimal pH for peroxidase activity for the specific sample type. The four plant root extracts showed an assay pH optimum of 7.5 for the Tamarindus indica (tamarind) and Eichhornia crassipes (water hyacinth), pH 5.5 for Dracaena surculosa (spotted dracaena) and pH 7.0 for Caulerpa lentillifera (grapes seaweeds) using Maehly and Chance method. Determination of peroxidase at 510 nm of the four extracts indicated that, spotted dracaena gave the highest peroxidase activity with 361.07 U ml -1 , followed by tamarind with 57.11 U ml -1 , then water hyacinth with 29.39 U m -1 and lastly, grapes seaweeds with 7.55 U ml -1 . The specific peroxidase activities of the spotted dracaena, water hyacinth, tamarind and grapes seaweeds are 0.3224, 0.2048, 0.0721 and 0.0341 U mg -1 respectively. The peroxidase of the four plant tissues that were kept at ultra low personal freezer for almost a week was degraded. (Authors)

  12. Selenium-Enriched Foods Are More Effective at Increasing Glutathione Peroxidase (GPx) Activity Compared with Selenomethionine: A Meta-Analysis

    Science.gov (United States)

    Bermingham, Emma N.; Hesketh, John E.; Sinclair, Bruce R.; Koolaard, John P.; Roy, Nicole C.

    2014-01-01

    Selenium may play a beneficial role in multi-factorial illnesses with genetic and environmental linkages via epigenetic regulation in part via glutathione peroxidase (GPx) activity. A meta-analysis was undertaken to quantify the effects of dietary selenium supplementation on the activity of overall GPx activity in different tissues and animal species and to compare the effectiveness of different forms of dietary selenium. GPx activity response was affected by both the dose and form of selenium (p selenium supplementation on GPx activity (p selenium supply include red blood cells, kidney and muscle. The meta-analysis identified that for animal species selenium-enriched foods were more effective than selenomethionine at increasing GPx activity. PMID:25268836

  13. An enzyme-immunobinding assay for fast screening of expression of tissue plasminogen activator cDNA in E. coli

    International Nuclear Information System (INIS)

    Tang, J.C.T.; Li, S.H.

    1984-01-01

    Tissue plasminogen activator (TPA) has been isolated from normal human tissues and certain human cell lines in culture. The enzyme is a serine protease which converts an inactive zymogen, plasminogen to plasmin, and causes lysis of fibrin clots. The high affinity of TPA for fibrin indicates that it is a potential thrombolytic agent and is superior to urokinase-like plasminogen activators. Recently, TPA has been cloned and expressed in E. coli. Using TPA as a model protein, the authors report here the development of a direct, sensitive enzyme-immunoassay for the screening of a cDNA expression library using specific antibodies and peroxidase-labeled second antibody

  14. Zinc affects differently growth, photosynthesis, antioxidant enzyme activities and phytochelatin synthase expression of four marine diatoms.

    Science.gov (United States)

    Nguyen-Deroche, Thi Le Nhung; Caruso, Aurore; Le, Thi Trung; Bui, Trang Viet; Schoefs, Benoît; Tremblin, Gérard; Morant-Manceau, Annick

    2012-01-01

    Zinc-supplementation (20 μM) effects on growth, photosynthesis, antioxidant enzyme activities (superoxide dismutase, ascorbate peroxidase, catalase), and the expression of phytochelatin synthase gene were investigated in four marine diatoms (Amphora acutiuscula, Nitzschia palea, Amphora coffeaeformis and Entomoneis paludosa). Zn-supplementation reduced the maximum cell density. A linear relationship was found between the evolution of gross photosynthesis and total chlorophyll content. The Zn treatment decreased the electron transport rate except in A. coffeaeformis and in E. paludosa at high irradiance. A linear relationship was found between the efficiency of light to evolve oxygen and the size of the light-harvesting antenna. The external carbonic anhydrase activity was stimulated in Zn-supplemented E. paludosa but was not correlated with an increase of photosynthesis. The total activity of the antioxidant enzymes did not display any clear increase except in ascorbate peroxidase activity in N. palea. The phytochelatin synthase gene was identified in the four diatoms, but its expression was only revealed in N. palea, without a clear difference between control and Zn-supplemented cells. Among the four species, A. paludosa was the most sensitive and A. coffeaeformis, the most tolerant. A. acutiuscula seemed to be under metal starvation, whereas, to survive, only N. palea developed several stress responses.

  15. Zinc Affects Differently Growth, Photosynthesis, Antioxidant Enzyme Activities and Phytochelatin Synthase Expression of Four Marine Diatoms

    Directory of Open Access Journals (Sweden)

    Thi Le Nhung Nguyen-Deroche

    2012-01-01

    Full Text Available Zinc-supplementation (20 μM effects on growth, photosynthesis, antioxidant enzyme activities (superoxide dismutase, ascorbate peroxidase, catalase, and the expression of phytochelatin synthase gene were investigated in four marine diatoms (Amphora acutiuscula, Nitzschia palea, Amphora coffeaeformis and Entomoneis paludosa. Zn-supplementation reduced the maximum cell density. A linear relationship was found between the evolution of gross photosynthesis and total chlorophyll content. The Zn treatment decreased the electron transport rate except in A. coffeaeformis and in E. paludosa at high irradiance. A linear relationship was found between the efficiency of light to evolve oxygen and the size of the light-harvesting antenna. The external carbonic anhydrase activity was stimulated in Zn-supplemented E. paludosa but was not correlated with an increase of photosynthesis. The total activity of the antioxidant enzymes did not display any clear increase except in ascorbate peroxidase activity in N. palea. The phytochelatin synthase gene was identified in the four diatoms, but its expression was only revealed in N. palea, without a clear difference between control and Zn-supplemented cells. Among the four species, A. paludosa was the most sensitive and A. coffeaeformis, the most tolerant. A. acutiuscula seemed to be under metal starvation, whereas, to survive, only N. palea developed several stress responses.

  16. Colorimetric detection of glucose based on ficin with peroxidase-like activity

    Science.gov (United States)

    Pang, Yanjiao; Huang, Zili; Yang, Yufang; Long, Yijuan; Zheng, Huzhi

    2018-01-01

    In this work, we developed a colorimetric biosensing system for glucose detection by coupling the peroxidase-like of ficin and the glucose oxidase (GOx). GOx can catalyze the oxidation of glucose to produce H2O2, then, ficin catalyzes the oxidation of peroxidase substrate 3,3‧,5,5‧-tetramethylbenzidine (TMB) by H2O2 to produce a blue color reaction. The present sensing system showed a linear response toward glucose detection over range of 2.0-100 μM with a detection limit of 0.5 μM. This system is simple, low cost, highly sensitive and selective for glucose detection, and was also applied to measuring glucose in human serum. Furthermore, in order to expand the application of ficin in biological sensing, we immobilized ficin onto the SiO2@Fe3O4 NPs, which exhibited the merits of recycling as well as allowing the repeated detection of glucose. Thus it may provide great potential applications in biomedicine, biotechnology and environmental chemistry.

  17. Tobacco Mosaic Virus with Peroxidase-Like Activity for Cancer Cell Detection through Colorimetric Assay.

    Science.gov (United States)

    Guo, Jiawang; Zhao, Xia; Hu, Jun; Lin, Yuan; Wang, Qian

    2018-01-22

    Cell-based ELISA (CELLISA) has been widely used in disease diagnosis due to its simplicity and low cost. Recently, peroxidase-like nanomaterials have emerged as promising systems for CELLISA applications. In this work, tobacco mosaic virus (TMV) was simultaneously tailored with peroxidase-like inorganic nanoparticles (platinum nanoparticles) and cancer cell target groups (folic acid, FA) to obtain TMV-FA-Pt nanoparticles for cancer cell detection. Induced by the uniformly distributed reactive groups and well-defined structure of the TMV particle, platinum nanoparticles could be grown in situ on the exterior surface of TMV with excellent monodispersity and uniform spatial distribution. Meanwhile, FA with a PEG 1000 linker was successfully conjugated to the coat proteins of TMV through the Cu(I)-catalyzed alkyne-azide cycloaddition reaction, an efficient "click" chemistry. Our study demonstrated that the resultant TMV-FA-Pt had specific affinity to cancer cells and was successfully used to detect cancer cells through CELLISA. Less than 1.0 × 10 4 cells/mL of cancer cells could be readily detected.

  18. Change in catalase and peroxidase activity in rat blood in case of combined burn and radiation injury

    International Nuclear Information System (INIS)

    Abramova, L.P.; Simonova, L.N.

    1982-01-01

    The peroxidase activity of blood and catalase activity were studied in white rats, subjected to whole-body X-irradiation with the dose 129 mC/kg and burn injury (20% of body surface) of 3A-3B degree and also combined burn and radiation injury. It is established that catalase activity was decreased in all groups and at all terms of the investigation. The changes in the blood peroxide activity were of phase character and normalized only by 14th day. The peroxide activity restores to intact level only by 30th day in animals with burn and radiation injury, that testifies to heavier course of the desease and to protracted character of recovery processes

  19. Chemical form of selenium affects its uptake, transport, and glutathione peroxidase activity in the human intestinal Caco-2 cell model.

    Science.gov (United States)

    Zeng, Huawei; Jackson, Matthew I; Cheng, Wen-Hsing; Combs, Gerald F

    2011-11-01

    Determining the effect of selenium (Se) chemical form on uptake, transport, and glutathione peroxidase activity in human intestinal cells is critical to assess Se bioavailability at nutritional doses. In this study, we found that two sources of L-selenomethionine (SeMet) and Se-enriched yeast each increased intracellular Se content more effectively than selenite or methylselenocysteine (SeMSC) in the human intestinal Caco-2 cell model. Interestingly, SeMSC, SeMet, and digested Se-enriched yeast were transported at comparable efficacy from the apical to basolateral sides, each being about 3-fold that of selenite. In addition, these forms of Se, whether before or after traversing from apical side to basolateral side, did not change the potential to support glutathione peroxidase (GPx) activity. Although selenoprotein P has been postulated to be a key Se transport protein, its intracellular expression did not differ when selenite, SeMSC, SeMet, or digested Se-enriched yeast was added to serum-contained media. Taken together, our data show, for the first time, that the chemical form of Se at nutritional doses can affect the absorptive (apical to basolateral side) efficacy and retention of Se by intestinal cells; but that, these effects are not directly correlated to the potential to support GPx activity.

  20. Enzyme activity assay of glycoprotein enzymes based on a boronate affinity molecularly imprinted 96-well microplate.

    Science.gov (United States)

    Bi, Xiaodong; Liu, Zhen

    2014-12-16

    Enzyme activity assay is an important method in clinical diagnostics. However, conventional enzyme activity assay suffers from apparent interference from the sample matrix. Herein, we present a new format of enzyme activity assay that can effectively eliminate the effects of the sample matrix. The key is a 96-well microplate modified with molecularly imprinted polymer (MIP) prepared according to a newly proposed method called boronate affinity-based oriented surface imprinting. Alkaline phosphatase (ALP), a glycoprotein enzyme that has been routinely used as an indicator for several diseases in clinical tests, was taken as a representative target enzyme. The prepared MIP exhibited strong affinity toward the template enzyme (with a dissociation constant of 10(-10) M) as well as superb tolerance for interference. Thus, the enzyme molecules in a complicated sample matrix could be specifically captured and cleaned up for enzyme activity assay, which eliminated the interference from the sample matrix. On the other hand, because the boronate affinity MIP could well retain the enzymatic activity of glycoprotein enzymes, the enzyme captured by the MIP was directly used for activity assay. Thus, additional assay time and possible enzyme or activity loss due to an enzyme release step required by other methods were avoided. Assay of ALP in human serum was successfully demonstrated, suggesting a promising prospect of the proposed method in real-world applications.

  1. In situ detection of microbial c-type cytochrome based on intrinsic peroxidase-like activity using screen-printed carbon electrode.

    Science.gov (United States)

    Wen, Junlin; He, Daigui; Yu, Zhen; Zhou, Shungui

    2018-08-15

    C-type cytochromes (c-cyts) facilitate microbial extracellular electron transfer and play critical roles in biogeochemical cycling, bioelectricity generation and bioremediation. In this study, a simple and effective method has been developed to detect microbial c-cyts by means of peroxidase mimetic reaction on screen-printed carbon electrode (SPCE). To this end, bacteria cells were immobilized onto the working electrode surface of SPCE by a simple drop casting. After introducing 3,3',5,5'-tetramethylbenzidine (TMB) solution, microbial c-cyts with peroxidase-like activity catalyze the oxidation of TMB in the presence of hydrogen peroxide. The oxidized TMB was electrochemically determined and the current signal was employed to calculate the c-cyts content. This electrochemical method is highly sensitive for microbial c-cyts with a low detection limit of 40.78 fmol and a wide detection range between 51.70 fmol and 6.64 pmol. Moreover, the proposed technique can be universally expanded to detect c-cyts in other bacteria species such as Fontibacter ferrireducens, Pseudomonas aeruginosa, Comamonas guangdongensis and Escherichia coli. Furthermore, the proposed method confers an in situ facile and quantitative c-cyts detection without any destructive sample preparations, complex electrode modifications and expensive enzyme- or metal particle- based signal amplification. The suggested method advances an intelligent strategy for in situ quantification of microbial c-cyts and consequently holds promising application potential in microbiology and environmental science. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Halide peroxidase in tissues that interact with bacteria in the host squid Euprymna scolopes.

    Science.gov (United States)

    Small, A L; McFall-Ngai, M J

    1999-03-15

    An enzyme with similarities to myeloperoxidase, the antimicrobial halide peroxidase in mammalian neutrophils, occurs abundantly in the light organ tissue of Euprymna scolopes, a squid that maintains a beneficial association with the luminous bacterium Vibrio fischeri. Using three independent assays typically applied to the analysis of halide peroxidase enzymes, we directly compared the activity of the squid enzyme with that of human myeloperoxidase. One of these methods, the diethanolamine assay, confirmed that the squid peroxidase requires halide ions for its activity. The identification of a halide peroxidase in a cooperative bacterial association suggested that this type of enzyme can function not only to control pathogens, but also to modulate the interactions of host animals with their beneficial partners. To determine whether the squid peroxidase functions under both circumstances, we examined its distribution in a variety of host tissues, including those that typically interact with bacteria and those that do not. Tissues interacting with bacteria included those that have specific cooperative associations with bacteria (i.e., the light organ and accessory nidamental gland) and those that have transient nonspecific interactions with bacteria (i.e., the gills, which clear the cephalopod circulatory system of invading microorganisms). These bacteria-associated tissues were compared with the eye, digestive gland, white body, and ink-producing tissues, which do not typically interact directly with bacteria. Peroxidase enzyme assays, immunocytochemical localization, and DNA-RNA hybridizations showed that the halide-dependent peroxidase is consistently expressed in high concentration in tissues that interact bacteria. Elevated levels of the peroxidase were also found in the ink-producing tissues, which are known to have enzymatic pathways associated with antimicrobial activity. Taken together, these data suggest that the host uses a common biochemical response to

  3. Enzyme activity and seedling growth of soybean seeds under accelerated aging

    Directory of Open Access Journals (Sweden)

    Yadollhhi Nooshabadi S.J.

    2013-11-01

    Full Text Available Seed aging is the main problem of seed storage. Changes of bio-chemical and reduction of seedling growth are consequence of seed deterioration. An experiment was conducted to evaluate the effects of accelerated aging on soybean seed germination indexes and enzyme activity. Seeds were incubated in closed plastic boxes for the accelerated aging treatments. Three accelerate aging regimes were performed by placing seeds at 41°C and relative humidity (RH of 90-100 % for 0, 2, 4, 6 and 8 days periods. Our results showed that increasing aging duration resulted higher reduction in germination characteristics, catalase and ascorbate peroxidase. Germination percentage, means time to germination, germination index, normal seedling percentage and enzyme activity decrease significantly.

  4. Purification and characterization of lignin peroxidases from Penicillium decumbens P6

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.S.; Yuan, H.L.; Wang, H.X.; Chen, W.X. [China Agricultural University, Beijing (China). College of Biological Science

    2005-06-01

    Peroxidases are essential enzymes in biodegradation of lignin and lignite which have been investigated intensively in the white-rot fungi. This is the first report of purification and characterization of lignin peroxidase from Penicillium sp. P6 as lignite degradation fungus. The results indicated that the lignin peroxidase of Penicillium decumbens P6 had physical and chemical properties and a N-terminal amino acid sequence different from the lignin peroxidases of white-rot fungi. The lignin peroxidase was isolated from a liquid culture of P. decumbens P6. This enzyme had a molecular weight of 46.3 KDa in SDS-PAGE and exhibited greater activity, temperature stability and wider pH range than those previously reported. The isolation procedure involved (NH{sub 4}){sub 2}SO{sub 4} precipitation, ion-exchange chromatography on DEAE-cellulose and CM-cellulose, gel filtration on Sephadex G-100, and non-denaturing, discontinuous polyacrylamide gel electrophoresis. The K{sub m} and V{sub max} values of this enzyme using veratryl alcohol as substrate were 0.565 mmol L{sup -1} and 0.088 mmol (mg protein){sup -1} min{sup -1} respectively. The optimum pH of P6 lignin peroxidase was 4.0, and 70.6% of the relative activity was remained at pH 9.0. The optimum temperature of the enzyme was 45{sup o}C.

  5. Peroxidase activity and sensory quality of ready to cook mixed vegetables for soup: combined effect of biopreservatives and refrigerated storage

    Directory of Open Access Journals (Sweden)

    María Victoria Alvarez

    2015-03-01

    Full Text Available Enzymatic senescence processes and browning of fresh cut vegetables negatively affect their sensory properties and nutritional value and finally result in the rejection of affected products by consumers. In order to prevent quality decay, the combined effects of natural antioxidants and storage temperature on peroxidase activity and sensory attributes (overall visual quality, browning and odor of individual and mixed vegetables for soup (butternut squash, leek and celery were evaluated. Fresh cut vegetables were treated with antioxidant solutions as tea tree essential oil (15 μl/mL, propolis extract (15 μl/mL and gallic acid (2 mg/mL and stored at optimal (5 °C and abusive (15 °C temperature for a maximum of 14 days. The application of natural preservatives, plus optimal storage conditions, exerted significant inhibitory effects in peroxidase activity of squash, celery and mixed vegetables throughout the storage. Furthermore, propolis treatment applied on mixed vegetables retarded browning appearance and preserved the visual quality for a longer period when compared to untreated product.

  6. Fenóis totais, peroxidase e suas relações com a compatibilidade de mudas de pessegueiro interenxertadas Total phenols content, peroxidase activity and their relationship with the compatibility of the intergrafted seedlings of peach tree

    Directory of Open Access Journals (Sweden)

    Charles Allan Telles

    2009-02-01

    Full Text Available O conhecimento das relações entre porta-enxerto e copa é vital para produção de mudas sem problemas de compatibilidade. Nesse sentido, a atividade de peroxidases e a concentração de fenóis apresentam grande importância na união entre enxerto e porta-enxerto, influenciando na resposta de compatibilidade de enxertia. Objetivou-se, neste trabalho, avaliar a compatibilidade de enxertia em mudas de pessegueiro interenxertadas, quantificando a atividade da peroxidase e a concentração dos fenóis totais em cultivares do gênero Prunus, no período de crescimento vegetativo e de repouso. Amostras da casca foram processadas e quantificadas por espectrofotometria. Os tratamentos foram a combinação de dois porta-enxertos de pessegueiro ('Okinawa' e 'Capdeboscq', com dois interenxertos de ameixeira ('Irati' e 'Reubennel' e duas copas ('Chimarrita' e 'Coral', mais o damasqueiro Japonês e cerejeira 'Capulin', cultivados no viveiro da Embrapa Transferência de Tecnologia, Canoinhas-SC. O delineamento experimental foi inteiramente ao acaso, com três repetições e três plantas por parcela. Concluiu-se que a atividade da peroxidase e os fenóis totais apresentaram baixa variação entre o pessegueiro e a ameixeira, sendo compatíveis entre si. A atividade da peroxidase e os fenóis totais foram superiores no período de repouso das mudas. O damasqueiro e a cerejeira apresentaram alta incompatibilidade, quando enxertados sobre porta-enxertos de pessegueiro.The understanding of the biochemical relation between rootstock and scion is very important for the production of seedlings without incompatibility problems. The activity of peroxidases and the phenol concentration are very important to the union between scion and rootstock, influencing the graft compatibility. This work aimed to analyze the compatibility of graft in peach tree intergrafted seedlings, to determine the peroxidase activity and total phenols in cultivars of Prunus, during the

  7. Purification and characterization of an intracellular peroxidase from Streptomyces cyaneus.

    OpenAIRE

    Mliki, A; Zimmermann, W

    1992-01-01

    An intracellular peroxidase (EC 1.11.1.7) from Streptomyces cyaneus was purified to homogeneity. The enzyme had a molecular weight of 185,000 and was composed of two subunits of equal size. It had an isoelectric point of 6.1. The enzyme had a peroxidase activity toward o-dianisidine with a Km of 17.8 microM and a pH optimum of 5.0. It also showed catalase activity with a Km of 2.07 mM H2O2 and a pH optimum of 8.0. The purified enzyme did not catalyze C alpha-C beta bond cleavage of 1,3-dihydr...

  8. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Energy Technology Data Exchange (ETDEWEB)

    Semsang, Nuananong, E-mail: nsemsang@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, LiangDeng [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29–60 keV and ion fluences of 1 × 10{sup 16} ions cm{sup −2}. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  9. Polyphenol oxidase and peroxidase in different sugarcane cultivars, in Presidente Prudente region; Polifenoloxidases e peroxidase em diferentes variedades de cana-de-acucar na regiao de Presidente Prudente

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Tadeu A.; Gomes, Danilo B.; Marques, Patricia A.A.; Alves, Vagner C. [Universidade do Oeste Paulista (UNOESTE), Presidente Prudente, SP (Brazil). Curso de Agronomia], Emails: tmarques@unoeste.br, pmarques@unoeste.br, vagner@unoeste.br

    2009-07-01

    The objective in present work was compare three sugarcane cultivars (RB 72-454, RB 86-7515, IAC 86-2480), evaluating the content of polyphenoloxidase and peroxidase. These determinations had aimed at to detect possible differences between varieties thus and being to differentiate them with regard to the products most interesting to be elaborated, ethanol production or sugar production. The varieties had presented differences of behavior for studied enzymes. The activity of polyphenoloxidase was superior the activity of peroxidase. The enzyme peroxidase was presented in bigger indices in the dry and cold periods. The enzyme polyphenoloxidase was presented well changeable, but with strong trend of bigger values in the rainy periods. It can be said that distinct periods for the best use of the varieties in the sugar production or alcohol exist. (author)

  10. Monovalent Cation Activation of the Radical SAM Enzyme Pyruvate Formate-Lyase Activating Enzyme.

    Science.gov (United States)

    Shisler, Krista A; Hutcheson, Rachel U; Horitani, Masaki; Duschene, Kaitlin S; Crain, Adam V; Byer, Amanda S; Shepard, Eric M; Rasmussen, Ashley; Yang, Jian; Broderick, William E; Vey, Jessica L; Drennan, Catherine L; Hoffman, Brian M; Broderick, Joan B

    2017-08-30

    Pyruvate formate-lyase activating enzyme (PFL-AE) is a radical S-adenosyl-l-methionine (SAM) enzyme that installs a catalytically essential glycyl radical on pyruvate formate-lyase. We show that PFL-AE binds a catalytically essential monovalent cation at its active site, yet another parallel with B 12 enzymes, and we characterize this cation site by a combination of structural, biochemical, and spectroscopic approaches. Refinement of the PFL-AE crystal structure reveals Na + as the most likely ion present in the solved structures, and pulsed electron nuclear double resonance (ENDOR) demonstrates that the same cation site is occupied by 23 Na in the solution state of the as-isolated enzyme. A SAM carboxylate-oxygen is an M + ligand, and EPR and circular dichroism spectroscopies reveal that both the site occupancy and the identity of the cation perturb the electronic properties of the SAM-chelated iron-sulfur cluster. ENDOR studies of the PFL-AE/[ 13 C-methyl]-SAM complex show that the target sulfonium positioning varies with the cation, while the observation of an isotropic hyperfine coupling to the cation by ENDOR measurements establishes its intimate, SAM-mediated interaction with the cluster. This monovalent cation site controls enzyme activity: (i) PFL-AE in the absence of any simple monovalent cations has little-no activity; and (ii) among monocations, going down Group 1 of the periodic table from Li + to Cs + , PFL-AE activity sharply maximizes at K + , with NH 4 + closely matching the efficacy of K + . PFL-AE is thus a type I M + -activated enzyme whose M + controls reactivity by interactions with the cosubstrate, SAM, which is bound to the catalytic iron-sulfur cluster.

  11. High-Throughput Analysis of Enzyme Activities

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Guoxin [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    High-throughput screening (HTS) techniques have been applied to many research fields nowadays. Robot microarray printing technique and automation microtiter handling technique allows HTS performing in both heterogeneous and homogeneous formats, with minimal sample required for each assay element. In this dissertation, new HTS techniques for enzyme activity analysis were developed. First, patterns of immobilized enzyme on nylon screen were detected by multiplexed capillary system. The imaging resolution is limited by the outer diameter of the capillaries. In order to get finer images, capillaries with smaller outer diameters can be used to form the imaging probe. Application of capillary electrophoresis allows separation of the product from the substrate in the reaction mixture, so that the product doesn't have to have different optical properties with the substrate. UV absorption detection allows almost universal detection for organic molecules. Thus, no modifications of either the substrate or the product molecules are necessary. This technique has the potential to be used in screening of local distribution variations of specific bio-molecules in a tissue or in screening of multiple immobilized catalysts. Another high-throughput screening technique is developed by directly monitoring the light intensity of the immobilized-catalyst surface using a scientific charge-coupled device (CCD). Briefly, the surface of enzyme microarray is focused onto a scientific CCD using an objective lens. By carefully choosing the detection wavelength, generation of product on an enzyme spot can be seen by the CCD. Analyzing the light intensity change over time on an enzyme spot can give information of reaction rate. The same microarray can be used for many times. Thus, high-throughput kinetic studies of hundreds of catalytic reactions are made possible. At last, we studied the fluorescence emission spectra of ADP and obtained the detection limits for ADP under three different

  12. Peroxidase gene discovery from the horseradish transcriptome.

    Science.gov (United States)

    Näätsaari, Laura; Krainer, Florian W; Schubert, Michael; Glieder, Anton; Thallinger, Gerhard G

    2014-03-24

    Horseradish peroxidases (HRPs) from Armoracia rusticana have long been utilized as reporters in various diagnostic assays and histochemical stainings. Regardless of their increasing importance in the field of life sciences and suggested uses in medical applications, chemical synthesis and other industrial applications, the HRP isoenzymes, their substrate specificities and enzymatic properties are poorly characterized. Due to lacking sequence information of natural isoenzymes and the low levels of HRP expression in heterologous hosts, commercially available HRP is still extracted as a mixture of isoenzymes from the roots of A. rusticana. In this study, a normalized, size-selected A. rusticana transcriptome library was sequenced using 454 Titanium technology. The resulting reads were assembled into 14871 isotigs with an average length of 1133 bp. Sequence databases, ORF finding and ORF characterization were utilized to identify peroxidase genes from the 14871 isotigs generated by de novo assembly. The sequences were manually reviewed and verified with Sanger sequencing of PCR amplified genomic fragments, resulting in the discovery of 28 secretory peroxidases, 23 of them previously unknown. A total of 22 isoenzymes including allelic variants were successfully expressed in Pichia pastoris and showed peroxidase activity with at least one of the substrates tested, thus enabling their development into commercial pure isoenzymes. This study demonstrates that transcriptome sequencing combined with sequence motif search is a powerful concept for the discovery and quick supply of new enzymes and isoenzymes from any plant or other eukaryotic organisms. Identification and manual verification of the sequences of 28 HRP isoenzymes do not only contribute a set of peroxidases for industrial, biological and biomedical applications, but also provide valuable information on the reliability of the approach in identifying and characterizing a large group of isoenzymes.

  13. Thiol peroxidases mediate specific genome-wide regulation of gene expression in response to hydrogen peroxide

    OpenAIRE

    Fomenko, Dmitri E.; Koc, Ahmet; Agisheva, Natalia; Jacobsen, Michael; Kaya, Alaattin; Malinouski, Mikalai; Rutherford, Julian C.; Siu, Kam-Leung; Jin, Dong-Yan; Winge, Dennis R.; Gladyshev, Vadim N.

    2011-01-01

    Hydrogen peroxide is thought to regulate cellular processes by direct oxidation of numerous cellular proteins, whereas antioxidants, most notably thiol peroxidases, are thought to reduce peroxides and inhibit H2O2 response. However, thiol peroxidases have also been implicated in activation of transcription factors and signaling. It remains unclear if these enzymes stimulate or inhibit redox regulation and whether this regulation is widespread or limited to a few cellular components. Herein, w...

  14. Oxidative enzymes activity in sugarcane juice as a function of the planting system

    Directory of Open Access Journals (Sweden)

    Tadeu Alcides Marques

    2013-03-01

    Full Text Available In Brazil, the largest producer of sugarcane in the world, the industrial process transforms this crop into ethanol and/or granulated sugar. Some cultivars exhibit enzymatic browning in the extracted sugarcane juice at levels harmful to the manufacturing process of white granulated sugar. The objective of this study was to assess the effect of sugarcane straw used as soil coverage, the use of different planting systems, and treatments with hydrogel polymer on enzymatic activity. The cultivar RB 86 7515 was sampled for 8 months; the first sample was obtained by cutting the upper portion of the stalk at the internode, which was taken to the laboratory for determination of the enzymatic activity of polyphenoloxidase (PPO and peroxidase (POD. The soil coverage with different forms of straw as well as the planting systems did not change the enzymatic activity of polyphenoloxidase (PPO and peroxidase (POD. The polyphenoloxidase (PPO activity increased with the use of a polymer due to increased polyphenoloxidase (PPO activity in the groove system. The enzymes studied showed changes in activity during the experimental period. The production of sugar at the end of the season (August to November avoids the periods of highest enzymatic activity.

  15. [Characteristics of soil organic carbon and enzyme activities in soil aggregates under different vegetation zones on the Loess Plateau].

    Science.gov (United States)

    Li, Xin; Ma, Rui-ping; An, Shao-shan; Zeng, Quan-chao; Li, Ya-yun

    2015-08-01

    In order to explore the distribution characteristics of organic carbon of different forms and the active enzymes in soil aggregates with different particle sizes, soil samples were chosen from forest zone, forest-grass zone and grass zone in the Yanhe watershed of Loess Plateau to study the content of organic carbon, easily oxidized carbon, and humus carbon, and the activities of cellulase, β-D-glucosidase, sucrose, urease and peroxidase, as well as the relations between the soil aggregates carbon and its components with the active soil enzymes were also analyzed. It was showed that the content of organic carbon and its components were in order of forest zone > grass zone > forest-grass zone, and the contents of three forms of organic carbon were the highest in the diameter group of 0.25-2 mm. The content of organic carbon and its components, as well as the activities of soil enzymes were higher in the soil layer of 0-10 cm than those in the 10-20 cm soil layer of different vegetation zones. The activities of cellulase, β-D-glucosidase, sucrose and urease were in order of forest zone > grass zone > forest-grass zone. The peroxidase activity was in order of forest zone > forest-grass zone > grass zone. The activities of various soil enzymes increased with the decreasing soil particle diameter in the three vegetation zones. The activities of cellulose, peroxidase, sucrose and urease had significant positive correlations with the contents of various forms of organic carbon in the soil aggregates.

  16. Assessment of Behavior of Rice Root Peroxidase in the Presence of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammadzade

    2016-01-01

    Full Text Available Background Silver Nanoparticles (AgNPs can change proteins function and structure. The increased production and high surface reactivity of silver nanoparticles, has interested researchers to study the interactions of these particles with biomolecules. Objectives The present study aimed to show the effects of AgNPs on rice plant root peroxidase enzyme and the interaction quality between silver nanoparticles and the enzyme. Materials and Methods Extracted peroxidase enzyme of rice plant root was treated by AgNPs at concentrations of 0, 20, 40, 80, 100mg/L for 2, 7 and 24 hours. The experiment was done with 15 treatments for measuring the peroxidase enzyme activity using the spectrophotometry method at a wavelength of 470. Results Low concentrations of AgNPs and short incubation times can have the maximum positive impact on the peroxidase activity, and in the present study the highest activity was seen at a concentration of 40 mg/L and two hours of incubation time. Conclusions This study suggests that changes of enzyme activity can occur as a result of the effect of silver nanoparticles on enzyme conformation, increase of reactive environment pH, and amount of substrate and enzyme stability.

  17. Markers of oxidative stress and erythrocyte antioxidant enzyme activity in older men and women with differing physical activity.

    Science.gov (United States)

    Rowiński, Rafał; Kozakiewicz, Mariusz; Kędziora-Kornatowska, Kornelia; Hübner-Woźniak, Elżbieta; Kędziora, Józef

    2013-11-01

    The aim of the present study was to examine the relationship between markers of oxidative stress and erythrocyte antioxidant enzyme activity and physical activity in older men and women. The present study included 481 participants (233 men and 248 women) in the age group 65-69 years (127 men and 125 women) and in the age group 90 years and over (106 men and 123 women). The classification of respondents by physical activity was based on answers to the question if, in the past 12 months, they engaged in any pastimes which require physical activity. The systemic oxidative stress status was assessed by measuring plasma iso-PGF2α and protein carbonyl concentration as well as erythrocyte antioxidant enzymes activity, i.e., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). The concentration of plasma iso-PGF2α and protein carbonyls (CP) was lower in groups of younger men and women compared to the respective older groups. In all examined groups, physical activity resulted in decrease of these oxidative stress markers and simultaneously caused adaptive increase in the erythrocyte SOD activity. Additionally, in active younger men CAT, GPx, and GR activities were higher than in sedentary ones. In conclusion, oxidative stress increase is age-related, but physical activity can reduce oxidative stress markers and induce adaptive increase in the erythrocyte antioxidant enzyme activity, especially SOD, even in old and very old men and women. © 2013.

  18. Extracellular enzyme activities during lignocellulose degradation by Streptomyces spp.: a comparative study of wild-type and genetically manipulated strains

    International Nuclear Information System (INIS)

    Ramachandra, M.; Crawford, D.L.; Pometto, A.L. III

    1987-01-01

    The wild-type ligninolytic actinomycete Streptomyces viridosporus T7A and two genetically manipulated strains with enhanced abilities to produce a water-soluble lignin degradation intermediate, an acid-precipitable polymeric lignin (APPL), were grown on lignocellulose in solid-state fermentation cultures. Culture filtrates were periodically collected, analyzed for APPL, and assayed for extracellular lignocellulose-catabolizing enzyme activities. Two APPL-overproducing strains, UV irradiation mutant T7A-81 and protoplast fusion recombinant SR-10, had higher and longer persisting peroxidase, esterase, and endoglucanase activities than did the wild-type strain T7A. Results implicated one or more of these enzymes in lignin solubilization. Only mutant T7A-81 had higher xylanase activity than the wild type. The peroxidase was induced by both lignocellulose and APPL. This extracellular enzyme has some similarities to previously described ligninases in fungi. This is the first report of such an enzyme in Streptomyces spp. Four peroxidase isozymes were present, and all catalyzed the oxidation of 3,4-dihydroxyphenylalanine, while one also catalyzed hydrogen peroxide-dependent oxidation of homoprotocatechuic acid and caffeic acid. Three constitutive esterase isozymes were produced which differed in substrate specificity toward α-naphthyl acetate and α-naphthyl butyrate. Three endoglucanase bands, which also exhibited a low level of xylanase activity, were identified on polyacrylamide gels as was one xylanase-specific band. There were no major differences in the isoenzymes produced by the different strains. The probable role of each enzyme in lignocellulose degradation is discussed

  19. Effect of Ethanol on Germination and Enzyme Activities in Finger millet (Eleusine coracana Gaertn. Seeds

    Directory of Open Access Journals (Sweden)

    S.S. Kulkarni

    2014-08-01

    Full Text Available Influence of ethanol the end product of alcoholic fermentation on the growth of finger millet (var. GPU-28, CO-9 seedlings of two finger millet was studied as a means of evaluating growth responses under anoxia. The germination was delayed by ethanol treatment in case of both the cultivars. Ethanol treatment affected the growth of both radicle and coleoptile of seedlings. In this respect the radicle growth is more sensitive to ethanol than the coleoptile in both varieties of finger millet. The activities of enzymes nitrate reductase, ATPase, acid phosphatase, amylase were reduced by alcohol treatment in germinating seeds of both the cultivars. However, lower concentration of alcohol (1% caused stimulation of peroxidase in var. CO-9. In case of var. GPU-28 showed stimulation of enzyme alkaline phosphatase in both concentration of alcohol.

  20. Pathogenicity and cell wall-degrading enzyme activities of some ...

    African Journals Online (AJOL)

    Dr. J. T. Ekanem

    2005-12-17

    Dec 17, 2005 ... be attributed to the activities of these cell wall degrading enzymes. Keywords: Cowpea ... bacteria have long been known to produce enzymes capable of ... Inoculated seeds were sown in small plastic pots filled with steam- ...

  1. Not so monofunctional-a case of thermostable Thermobifida fusca catalase with peroxidase activity

    NARCIS (Netherlands)

    Lončar, Nikola; Fraaije, Marco W

    Thermobifida fusca is a mesothermophilic organism known for its ability to degrade plant biomass and other organics, and it was demonstrated that it represents a rich resource of genes encoding for potent enzymes for biocatalysis. The thermostable catalase from T. fusca has been cloned and

  2. Effects of Copper Oxide Nanoparticles on Antioxidant Enzyme Activities and on Tissue Accumulation of Oreochromis niloticus.

    Science.gov (United States)

    Tunçsoy, Mustafa; Duran, Servet; Ay, Özcan; Cicik, Bedii; Erdem, Cahit

    2017-09-01

    Accumulation of copper oxide nanoparticles (CuO NPs) in gill, liver and muscle tissues of Oreochromis niloticus and its effects on superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities in gill and liver tissues were studied after exposing the fish to 20 µg/L Cu over 15 days. Copper levels and enzyme activities in tissues were determined using spectrophotometric (ICP-AES and UV) techniques respectively. No mortality was observed during the experiments. Copper levels increased in gill and liver tissues of O. niloticus compared to control when exposed to CuO NPs whereas exposure to metal had no effect on muscle level at the end of the exposure period. Highest accumulation of copper was observed in liver while no accumulation was detected in muscle tissue. SOD, CAT activities decreased and GPx activity increased in gill and liver tissues when exposed to CuO NPs.

  3. Copper-Based Metal-Organic Framework Nanoparticles with Peroxidase-Like Activity for Sensitive Colorimetric Detection of Staphylococcus aureus.

    Science.gov (United States)

    Wang, Shuqin; Deng, Wenfang; Yang, Lu; Tan, Yueming; Xie, Qingji; Yao, Shouzhuo

    2017-07-26

    Cu-MOF nanoparticles with an average diameter of 550 nm were synthesized from 2-aminoterephthalic acid and Cu(NO 3 ) 2 by a mixed solvothermal method. The Cu-MOF nanoparticles can show peroxidase-like activity that can catalyze 3,3',5,5'-tetramethylbenzidine to produce a yellow chromogenic reaction in the presence of H 2 O 2 . The presence of abundant amine groups on the surfaces of Cu-MOF nanoparticles enables facile modification of Staphylococcus aureus (S. aureus) aptamer on Cu-MOF nanoparticles. By combining Cu-MOF-catalyzed chromogenic reaction with aptamer recognition and magnetic separation, a simple, sensitive, and selective colorimetric method for the detection of S. aureus was developed.

  4. Reduction of Diphenyl Diselenide and Analogs by Mammalian Thioredoxin Reductase Is Independent of Their Gluthathione Peroxidase-Like Activity: A Possible Novel Pathway for Their Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    João Batista Teixeira Rocha

    2010-10-01

    Full Text Available Since the successful use of the organoselenium drug ebselen in clinical trials for the treatment of neuropathological conditions associated with oxidative stress, there have been concerted efforts geared towards understanding the precise mechanism of action of ebselen and other organoselenium compounds, especially the diorganyl diselenides such as diphenyl diselenide, and its analogs. Although the mechanism of action of ebselen and other organoselenium compounds has been shown to be related to their ability to generally mimic native glutathione peroxidase (GPx, only ebselen however has been shown to serve as a substrate for the mammalian thioredoxin reductase (TrxR, demonstrating another component of its pharmacological mechanisms. In fact, there is a dearth of information on the ability of other organoselenium compounds, especially diphenyl diselenide and its analogs, to serve as substrates for the mammalian enzyme thioredoxin reductase. Interestingly, diphenyl diselenide shares several antioxidant and neuroprotective properties with ebselen. Hence in the present study, we tested the hypothesis that diphenyl diselenide and some of its analogs (4,4’-bistrifluoromethyldiphenyl diselenide, 4,4’-bismethoxy-diphenyl diselenide, 4.4’-biscarboxydiphenyl diselenide, 4,4’-bischlorodiphenyl diselenide, 2,4,6,2’,4’,6’-hexamethyldiphenyl diselenide could also be substrates for rat hepatic TrxR. Here we show for the first time that diselenides are good substrates for mammalian TrxR, but not necessarily good mimetics of GPx, and vice versa. For instance, bis-methoxydiphenyl diselenide had no GPx activity, whereas it was a good substrate for reduction by TrxR. Our experimental observations indicate a possible dissociation between the two pathways for peroxide degradation (either via substrate for TrxR or as a mimic of GPx. Consequently, the antioxidant activity of diphenyl diselenide and analogs can be attributed to their capacity to be

  5. Diverse effects of arsenic on selected enzyme activities in soil-plant-microbe interactions.

    Science.gov (United States)

    Lyubun, Yelena V; Pleshakova, Ekaterina V; Mkandawire, Martin; Turkovskaya, Olga V

    2013-11-15

    Under the influence of pollutants, enzyme activities in plant-microbe-soil systems undergo changes of great importance in predicting soil-plant-microbe interactions, regulation of metal and nutrient uptake, and, ultimately, improvement of soil health and fertility. We evaluated the influence of As on soil enzyme activities and the effectiveness of five field crops for As phytoextraction. The initial As concentration in soil was 50mg As kg(-1) soil; planted clean soil, unplanted polluted soil, and unplanted clean soil served as controls. After 10 weeks, the growth of the plants elevated soil dehydrogenase activity relative to polluted but unplanted control soils by 2.4- and 2.5-fold for sorghum and sunflower (respectively), by 3-fold for ryegrass and sudangrass, and by 5.2-fold for spring rape. Soil peroxidase activity increased by 33% with ryegrass and rape, while soil phosphatase activity was directly correlated with residual As (correlation coefficient R(2)=0.7045). We conclude that soil enzyme activities should be taken into account when selecting plants for phytoremediation. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Effect of irradiation on lysosomal enzyme activation in cultured macrophages

    International Nuclear Information System (INIS)

    Clarke, C.; Wills, E.D.

    1980-01-01

    The effect of γrays on lysosomal enzyme activity of normal and immune macrophages of DBA/2 mice cultured in vitro has been studied. A dose of 500 rad did not significantly affect lysosomal enzyme activity 3 hours after irradiation but caused the activity to increase to 1.4 times the control value 22.5 hours after irradiation. 22.5 hours after a dose of 3000 rad the enzyme activity increased to 2.5 times the control. Lysosomal enzyme activity of the macrophages was also markedly increased by immunization of the mice with D lymphoma cells, before culture in vitro, but irradiation of these cells with a dose of 500 rad caused a further increase in lysosomal enzyme activity. The results indicate that immunization and irradiation both cause stimulation of lysosomal enzyme activity in macrophages but that the mechanisms of activation are unlikely to be identical. (author)

  7. Effect of Sodium Fluoride Ingestion on Malondialdehyde Concentration and the Activity of Antioxidant Enzymes in Rat Erythrocytes

    Directory of Open Access Journals (Sweden)

    José A. Morales-González

    2010-06-01

    Full Text Available Fluoride intoxication has been shown to produce diverse deleterious metabolic alterations within the cell. To determine the effects of sodium fluoride (NaF treatment on malondialdehyde (MDA levels and on the activity of antioxidant enzymes in rat erythrocytes, Male Wistar rats were treated with 50 ppm of NaF or were untreated as controls. Erythrocytes were obtained from rats sacrificed weekly for up to eight weeks and the concentration of MDA in erythrocyte membrane was determined. In addition, the activity of the enzymes superoxide, dismutase, catalase, and glutathione peroxidase were determined. Treatment with NaF produces an increase in the concentration of malondialdehyde in the erythrocyte membrane only after the eight weeks of treatment. On the other hand, antioxidant enzyme activity was observed to increase after the fourth week of NaF treatment. In conclusion, intake of NaF produces alterations in the erythrocyte of the male rat, which indicates induction of oxidative stress.

  8. Quantum mechanical design of enzyme active sites.

    Science.gov (United States)

    Zhang, Xiyun; DeChancie, Jason; Gunaydin, Hakan; Chowdry, Arnab B; Clemente, Fernando R; Smith, Adam J T; Handel, T M; Houk, K N

    2008-02-01

    The design of active sites has been carried out using quantum mechanical calculations to predict the rate-determining transition state of a desired reaction in presence of the optimal arrangement of catalytic functional groups (theozyme). Eleven versatile reaction targets were chosen, including hydrolysis, dehydration, isomerization, aldol, and Diels-Alder reactions. For each of the targets, the predicted mechanism and the rate-determining transition state (TS) of the uncatalyzed reaction in water is presented. For the rate-determining TS, a catalytic site was designed using naturalistic catalytic units followed by an estimation of the rate acceleration provided by a reoptimization of the catalytic site. Finally, the geometries of the sites were compared to the X-ray structures of related natural enzymes. Recent advances in computational algorithms and power, coupled with successes in computational protein design, have provided a powerful context for undertaking such an endeavor. We propose that theozymes are excellent candidates to serve as the active site models for design processes.

  9. The Catalase Activity of Catalase-Peroxidases Is Modulated by Changes in the pKa of the Distal Histidine.

    Science.gov (United States)

    Machuqueiro, Miguel; Victor, Bruno; Switala, Jacek; Villanueva, Jacylyn; Rovira, Carme; Fita, Ignacio; Loewen, Peter C

    2017-05-02

    The unusual Met-Tyr-Trp adduct composed of cross-linked side chains along with an associated mobile Arg is essential for catalase activity in catalase-peroxidases. In addition, acidic residues in the entrance channel, in particular an Asp and a Glu ∼7 and ∼15 Å, respectively, from the heme, significantly enhance catalase activity. The mechanism by which these channel carboxylates influence catalase activity is the focus of this work. Seventeen new variants with fewer and additional acidic residues have been constructed and characterized structurally and for enzymatic activity, revealing that their effect on activity is roughly inversely proportional to their distance from the heme and adduct, suggesting that the electrostatic potential of the heme cavity may be affected. A discrete group of protonable residues are contained within a 15 Å sphere surrounding the heme iron, and a computational analysis reveals that the pK a of the distal His 112 , alone, is modulated within the pH range of catalase activity by the remote acidic residues in a pattern consistent with its protonated form having a key role in the catalase reaction cycle. The electrostatic potential also impacts the catalatic reaction through its influence on the charged status of the Met-Tyr-Trp adduct.

  10. The influence of non thermal coherent EMR with low intensity and extremely high frequency on total activity and isoenzyme composition of peroxidase

    International Nuclear Information System (INIS)

    Nerkararyan, A.V.; Shahinyan, M.A.; Khachatryan, A.V.; Vardevanyan, P.O.

    2011-01-01

    In this work the influence of non-thermal coherent electromagnetic radiation (EMR) with low intensity and extremely high frequency on intensity of wheat developing germ metabolism has been investigated. Particularly, total activity and isoenzymatic composition of peroxidase of germ cells have been determined during their growth. The role of water in formation of organism response reaction to the external physical field effect has also been investigated. It has been shown, that water appears to be a primary element of extremely high frequency EMR effect on bio system. Extremely high frequency EMR irradiation of germinating seeds and the cultivation of dry seeds and their germs by irradiated water stimulate peroxidase synthesis in germ cells. The redistribution of quantitative composition of peroxidase molecular forms takes place in germ cells effected by EMR with extremely high frequency and low intensity

  11. Effects of carbon ion irradiation on survival rate, catalase and peroxidase activity of alfalfa M1 under low temperature stress

    International Nuclear Information System (INIS)

    Wang Shuyang; Li Jinghua; Jiang Boling

    2014-01-01

    In this study, three kinds of alfalfa including Zhonglan 1, BC-04-477 and Ta Cheng were treated with different doses of "1"2C"6"+ (75 keV) heavy ion radiation, and then the influence of survival rate, catalase (CAT) and peroxidase (POD) activity of M1 with low temperature stress were tested. The results showed that under the condition of 400 Gy radiation dose, the survival rate and CAT activity of Zhonglan 1 under low temperature stress have increased by 33.3%, 56.3% respectively compared with those of the control group, while there was no difference in POD activity between those two groups. The survival rate, CAT and POD activity of BC-04-477 treated with low temperature have been improved by 33.3%, 69.2%, 5.1% respectively compared with those of the control group when the radiation dose was 400 Gy. Compared with those of the control group, the survival rate, CAT and POD activity of Ta Cheng under low temperature stress have been improved by 25%, 26%,22.8% respectively when the radiation dose was 800 Gy. These results indicate that the viability and the cold resistance ability of Zhong Lan 1, BC-04-477 and Ta Cheng can be improved by "1"2C"6"+ radiation. (authors)

  12. Physicochemical characteristcs and enzymatic activity of peroxidase and polyphenoloxidase in four genotypes of cupuaçu (Theobroma grandiflorum Willd ex-Spreng Schum submitted to freezingCaracterísticas físico-químicas e atividade da peroxidase e polifenoloxidase em genótipos de cupuaçu (Theobroma grandiflorum Willd ex-Spreng Schum submetidos ao congelamento

    Directory of Open Access Journals (Sweden)

    Salomão Rocha Martim

    2013-10-01

    Full Text Available During the freezing of fruits pulps, the enzyme activity is not finished completely. Sensory, nutritional and coloring changes may occur on fruits due to the action of oxidative enzymes such as peroxidase and polyphenoloxidase. The frozen cupuaçu pulps, sold in Brazil, have a shelf life of one year and become browned during this period. The aim of this study was to evaluate the effect of frozen storage on the physicochemical characteristics, polyphenoloxidase activity and soluble and ionically bound peroxidases presented in the pulps of four new cupuaçu genotypes over twelve months. The cupuaçu genotypes developed by the West Amazonian Agroforestry Research Center (EMBRAPA were pulped, frozen and stored at – 30 °C. The polyphenoloxidase of the four cupuaçu genotypes showed an increase in activity according to the storage time with peaks in the sixth, ninth and tenth months, but the peroxidases exhibited oscillations in the enzyme activity. The physicochemical properties of the pulps showed variations during the twelve months of storage under freezing. The vitamin C content of D 28-10 and P 3-10 genotypes decreased from the fourth and tenth months, respectively. Moreover P 9-8 e B 28-7 genotypes remained stable. In relation the acidity of citric acid, the B-28-7, D 28-10 and P 9-8 samples were not different, but P 3-10 genotype presented a reduction. The pH and total soluble solids of all genotypes decreased over the study period. There was an increase in sugar concentration of B 28-7, P 3-10 and P 9-8 genotypes, except for D 28-10 sample which remained unchanged. All genotypes were in accordance with physical-chemicals standards required by legislation, except for P 3-10 genotype that showed a lower acidity. In respect of the enzymatic parameters, there were variations in the activity of peroxidase and polyphenoloxidases of all genotypes. No congelamento de polpas de frutas a atividade enzimática não é completamente cessada. Podem

  13. Detection of Extracellular Enzyme Activities in Ganoderma neo-japonicum

    OpenAIRE

    Jo, Woo-Sik; Park, Ha-Na; Cho, Doo-Hyun; Yoo, Young-Bok; Park, Seung-Chun

    2011-01-01

    The ability of Ganoderma to produce extracellular enzymes, including β-glucosidase, cellulase, avicelase, pectinase, xylanase, protease, amylase, and ligninase was tested in chromogenic media. β-glucosidase showed the highest activity, among the eight tested enzymes. In particular, Ganoderma neo-japonicum showed significantly stronger activity for β-glucosidase than that of the other enzymes. Two Ganoderma lucidum isolates showed moderate activity for avicelase; however, Ganoderma neo-japonic...

  14. Ultraviolet-B- and ozone-induced biochemical changes in antioxidant enzymes of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Rao, M.V.; Paliyath, G.; Ormrod, D.P.

    1996-01-01

    Earlier studies with Arabidopsis thaliana exposed to ultraviolet B (UV-B) and ozone (O 3 ) have indicated the differential responses of superoxide dismutase and glutathione reductase. In this study, we have investigated whether A. thaliana genotype Landsberg erecta and its flavonoid-deficient mutant transparent testa (tt5) is capable of metabolizing UV-B- and O 3 -induced activated oxygen species by invoking similar antioxidant enzymes. UV-B exposure preferentially enhanced guaiacol-peroxidases, ascorbate peroxidase, and peroxidases specific to coniferyl alcohol and modified the substrate affinity of ascorbate peroxidase. O 3 exposure enhanced superoxide dismutase, peroxidases, glutathione reductase, and ascorbate peroxidase to a similar degree and modified the substrate affinity of both glutathione reductase and ascorbate peroxidase. Both UV-B and O 3 exposure enhanced similar Cu,Zn-superoxide dismutase isoforms. New isoforms of peroxidases and ascorbate peroxidase were synthesized in tt5 plants irradiated with UV-B. UV-B radiation, in contrast to O 3 , enhanced the activation oxygen species by increasing membrane-localized NADPH-oxidase activity and decreasing catalase activities. These results collectively suggest that (a) UV-B exposure preferentially induces peroxidase-related enzymes, whereas O 3 exposure invokes the enzymes of superoxide dismutase/ascorbate-glutathione cycle, and (b) in contrast to O 3 , UV-B exposure generated activated oxygen species by increasing NADPH-oxidase activity. 10 figs., 4 tabs

  15. Antioxidant enzyme activity and malondialdehyde levels can be modulated by Piper betle, tocotrienol rich fraction and Chlorella vulgaris in aging C57BL/6 mice.

    Science.gov (United States)

    Aliahmat, Nor Syahida; Noor, Mohd Razman Mohd; Yusof, Wan Junizam Wan; Makpol, Suzana; Ngah, Wan Zurinah Wan; Yusof, Yasmin Anum Mohd

    2012-12-01

    The aim of this study was to determine the erythrocyte antioxidant enzyme activity and the superoxide dismutase, catalase, glutathione peroxidase, and plasma malondialdehyde levels in aging mice and to evaluate how these measures are modulated by potential antioxidants, including the tocotrienol-rich fraction, Piper betle, and Chlorella vulgaris. One hundred and twenty male C57BL/6 inbred mice were divided into three age groups: young (6 months old), middle-aged (12 months old), and old (18 months old). Each age group consisted of two control groups (distilled water and olive oil) and three treatment groups: Piper betle (50 mg/kg body weight), tocotrienol-rich fraction (30 mg/kg), and Chlorella vulgaris (50 mg/kg). The duration of treatment for all three age groups was two months. Blood was withdrawn from the orbital sinus to determine the antioxidant enzyme activity and the malondialdehyde level. Piper betle increased the activities of catalase, glutathione peroxidase, and superoxide dismutase in the young, middle, and old age groups, respectively, when compared to control. The tocotrienol-rich fraction decreased the superoxide dismutase activity in the middle and the old age groups but had no effect on catalase or glutathione peroxidase activity for all age groups. Chlorella vulgaris had no effect on superoxide dismutase activity for all age groups but increased glutathione peroxidase and decreased catalase activity in the middle and the young age groups, respectively. Chlorella vulgaris reduced lipid peroxidation (malondialdehyde levels) in all age groups, but no significant changes were observed with the tocotrienol-rich fraction and the Piper betle treatments. We found equivocal age-related changes in erythrocyte antioxidant enzyme activity when mice were treated with Piper betle, the tocotrienol-rich fraction, and Chlorella vulgaris. However, Piper betle treatment showed increased antioxidant enzymes activity during aging.

  16. Antioxidant enzyme activity and malondialdehyde levels can be modulated by Piper betle, tocotrienol rich fraction and Chlorella vulgaris in aging C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    Nor Syahida Aliahmat

    2012-12-01

    Full Text Available OBJECTIVE: The aim of this study was to determine the erythrocyte antioxidant enzyme activity and the superoxide dismutase, catalase, glutathione peroxidase, and plasma malondialdehyde levels in aging mice and to evaluate how these measures are modulated by potential antioxidants, including the tocotrienol-rich fraction, Piper betle, and Chlorella vulgaris. METHOD: One hundred and twenty male C57BL/6 inbred mice were divided into three age groups: young (6 months old, middle-aged (12 months old, and old (18 months old. Each age group consisted of two control groups (distilled water and olive oil and three treatment groups: Piper betle (50 mg/kg body weight, tocotrienol-rich fraction (30 mg/kg, and Chlorella vulgaris (50 mg/kg. The duration of treatment for all three age groups was two months. Blood was withdrawn from the orbital sinus to determine the antioxidant enzyme activity and the malondialdehyde level. RESULTS: Piper betle increased the activities of catalase, glutathione peroxidase, and superoxide dismutase in the young, middle, and old age groups, respectively, when compared to control. The tocotrienol-rich fraction decreased the superoxide dismutase activity in the middle and the old age groups but had no effect on catalase or glutathione peroxidase activity for all age groups. Chlorella vulgaris had no effect on superoxide dismutase activity for all age groups but increased glutathione peroxidase and decreased catalase activity in the middle and the young age groups, respectively. Chlorella vulgaris reduced lipid peroxidation (malondialdehyde levels in all age groups, but no significant changes were observed with the tocotrienol-rich fraction and the Piper betle treatments. CONCLUSION: We found equivocal age-related changes in erythrocyte antioxidant enzyme activity when mice were treated with Piper betle, the tocotrienol-rich fraction, and Chlorella vulgaris. However, Piper betle treatment showed increased antioxidant enzymes

  17. Effect of drought stress and subsequent recovery on protein, carbohydrate contents, catalase and peroxidase activities in three chickpea (Cicer arietinum) cultivars

    NARCIS (Netherlands)

    Mafakheri, A.; Siosemardeh, A.; Bahramnejad, B.; Struik, P.C.; Sohrabi, Y.

    2011-01-01

    Drought stress is one of the major abiotic stresses in agriculture worldwide. This study was carried out to investigate the effects of drought stress and subsequent recovery on protein, carbohydrate content, catalase (CAT), and peroxidase (POX) activities in three varieties of chickpea (drought

  18. Effects of dietary menadione on the activity of antioxidant enzymes in abalone, Haliotis discus hannai Ino

    Science.gov (United States)

    Fu, Jinghua; Xu, Wei; Mai, Kangsen; Zhang, Wenbing; Feng, Xiuni; Liufu, Zhiguo

    2012-01-01

    A 240-day growth experiment in a re-circulating water system was conducted to investigate the effects of dietary menadione on the growth and antioxidant responses of abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 1.19 ± 0.01 g; shell length: 19.23 ± 0.01 mm) were fed to satiation with 3 semi-purified diets containing 0, 10, and 1 000 mg menadione sodium bisulfite (MSB)/kg, respectively. Results show that there were no significant differences in the rate of weight gain or in the daily increment in shell length of abalone among different treatments. Activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR) in viscera were significantly decreased with dietary menadione. However, activities of these enzymes except for GPX in muscle were increased. Therefore, antioxidant responses of abalone were increased in muscle and decreased in viscera by dietary menadione.

  19. Activities of some enzymes of lignin formation in reaction wood of Thuja orientalis, Metasequoia glyptostroboides and Robinia pseudoacacia.

    Science.gov (United States)

    Kutsuki, H; Higuchi, T

    1981-07-01

    The activities of the following five enzymes which are involved in the formation of lignin have been compared in reaction wood and in opposite wood: phenylalanine ammonia lyase (EC 4.3.1.5), caffeate 3-O-methyltransferase (EC 2.1.1.-), p-hydroxycinnamate: CoA ligase (EC 6.2.1.12), cinnamyl alcohol dehydrogenase (EC 1.1.1.-) and peroxidase (EC 1.11.1.7). The activities of the four first-named enzymes in the compression wood of Thuja orientalis L. and Metasequoia glyptostroboides Hu et Cheng were 2.8±1.4-fold and 2.6±1.5-fold higher than those in opposite wood, respectively, whereas peroxidase had the same level of activity in either type of wood. On the other hand, no differences were observed in the activities of the five enzymes between tension and opposite woods of Robinia pseudoacacia L. These findings are well in accord with the chemical structure of lignin in the compression and tension woods of the three species studied: high content of lignin rich in condensed units in compression wood, and little difference in lignin between tension and opposite woods.

  20. Seeing diabetes: visual detection of glucose based on the intrinsic peroxidase-like activity of MoS2 nanosheets

    Science.gov (United States)

    Lin, Tianran; Zhong, Liangshuang; Guo, Liangqia; Fu, Fengfu; Chen, Guonan

    2014-09-01

    Molybdenum disulfide (MoS2) has attracted increasing research interest recently due to its unique physical, optical and electrical properties, correlated with its 2D ultrathin atomic-layered structure. Until now, however, great efforts have focused on its applications such as lithium ion batteries, transistors, and hydrogen evolution reactions. Herein, for the first time, MoS2 nanosheets are discovered to possess an intrinsic peroxidase-like activity and can catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to produce a color reaction. The catalytic activity follows the typical Michaelis-Menten kinetics and is dependent on temperature, pH, H2O2 concentration, and reaction time. Based on this finding, a highly sensitive and selective colorimetric method for H2O2 and glucose detection is developed and applied to detect glucose in serum samples. Moreover, a simple, inexpensive, instrument-free and portable test kit for the visual detection of glucose in normal and diabetic serum samples is constructed by utilizing agarose hydrogel as a visual detection platform.Molybdenum disulfide (MoS2) has attracted increasing research interest recently due to its unique physical, optical and electrical properties, correlated with its 2D ultrathin atomic-layered structure. Until now, however, great efforts have focused on its applications such as lithium ion batteries, transistors, and hydrogen evolution reactions. Herein, for the first time, MoS2 nanosheets are discovered to possess an intrinsic peroxidase-like activity and can catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to produce a color reaction. The catalytic activity follows the typical Michaelis-Menten kinetics and is dependent on temperature, pH, H2O2 concentration, and reaction time. Based on this finding, a highly sensitive and selective colorimetric method for H2O2 and glucose detection is developed and applied to detect glucose in serum samples. Moreover, a simple, inexpensive

  1. Horseradish peroxidase-modified porous silicon for phenol monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kermad, A., E-mail: amina_energetique@yahoo.fr [Unité de Recherche Matériaux et Energies Renouvelables (URMER), Département de Physique, Faculté des Sciences, Université Abou Baker Belkaid, B.P. 119, Tlemcen 13000 (Algeria); Sam, S., E-mail: Sabrina.sam@polytechnique.edu [Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE), 02 Bd. Frantz-Fanon, B.P. 140, Alger-7 merveilles, Algiers (Algeria); Ghellai, N., E-mail: na_ghellai@yahoo.fr [Unité de Recherche Matériaux et Energies Renouvelables (URMER), Département de Physique, Faculté des Sciences, Université Abou Baker Belkaid, B.P. 119, Tlemcen 13000 (Algeria); Khaldi, K., E-mail: Khadidjaphy@yahoo.fr [Unité de Recherche Matériaux et Energies Renouvelables (URMER), Département de Physique, Faculté des Sciences, Université Abou Baker Belkaid, B.P. 119, Tlemcen 13000 (Algeria); Gabouze, N., E-mail: ngabouze@yahoo.fr [Centre de Recherche en Technologie des Semi-conducteurs pour l’Energétique (CRTSE), 02 Bd. Frantz-Fanon, B.P. 140, Alger-7 merveilles, Algiers (Algeria)

    2013-11-01

    Highlights: • Horseradish peroxidase enzyme (HRP) was covalently immobilized on porous silicon (PSi) surface. • Multistep strategy was used allowing the maintaining of the enzymatic activity of the immobilized enzyme. • Direct electron transfer has occurred between the immobilized enzyme and the surface. • Electrochemical measurements showed a response of HRP-modified PSi toward phenol in the presence of H{sub 2}O{sub 2}. -- Abstract: In this study, horseradish peroxidase enzyme (HRP) was covalently immobilized on porous silicon (PSi) surface using multistep strategy. First, acid terminations were generated on hydrogenated PSi surface by thermal hydrosilylation of undecylenic acid. Then, the carboxyl-terminated monolayer was transformed to active ester (succinimidyl ester) using N-hydroxysuccinimide (NHS) in the presence of the coupling agent N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide (EDC). Subsequently, the enzyme was anchored on the surface via an amidation reaction. The structure of the PSi layers was observed by scanning electron microscopy (SEM). Infrared spectroscopy (FTIR) and contact angle measurements confirmed the efficiency of the modification at each step of the functionalization. Cyclic voltammetry was recorded using the HRP-modified PSi as working electrode. The results show that the enzymatic activity of the immobilized HRP is preserved and in the presence of hydrogen peroxide, the enzyme oxidizes phenolic molecules which were subsequently reduced at the modified-PSi electrode.

  2. Horseradish peroxidase-modified porous silicon for phenol monitoring

    International Nuclear Information System (INIS)

    Kermad, A.; Sam, S.; Ghellai, N.; Khaldi, K.; Gabouze, N.

    2013-01-01

    Highlights: • Horseradish peroxidase enzyme (HRP) was covalently immobilized on porous silicon (PSi) surface. • Multistep strategy was used allowing the maintaining of the enzymatic activity of the immobilized enzyme. • Direct electron transfer has occurred between the immobilized enzyme and the surface. • Electrochemical measurements showed a response of HRP-modified PSi toward phenol in the presence of H 2 O 2 . -- Abstract: In this study, horseradish peroxidase enzyme (HRP) was covalently immobilized on porous silicon (PSi) surface using multistep strategy. First, acid terminations were generated on hydrogenated PSi surface by thermal hydrosilylation of undecylenic acid. Then, the carboxyl-terminated monolayer was transformed to active ester (succinimidyl ester) using N-hydroxysuccinimide (NHS) in the presence of the coupling agent N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide (EDC). Subsequently, the enzyme was anchored on the surface via an amidation reaction. The structure of the PSi layers was observed by scanning electron microscopy (SEM). Infrared spectroscopy (FTIR) and contact angle measurements confirmed the efficiency of the modification at each step of the functionalization. Cyclic voltammetry was recorded using the HRP-modified PSi as working electrode. The results show that the enzymatic activity of the immobilized HRP is preserved and in the presence of hydrogen peroxide, the enzyme oxidizes phenolic molecules which were subsequently reduced at the modified-PSi electrode

  3. Daily rhythms of catalase and glutathione peroxidase expression and activity are endogenously driven in the hippocampus and are modified by a vitamin A-free diet.

    Science.gov (United States)

    Navigatore-Fonzo, Lorena S; Delgado, Silvia M; Gimenez, Maria Sofia; Anzulovich, Ana C

    2014-01-01

    Alterations in enzymatic antioxidant defense systems lead to a deficit of cognitive functions and altered hippocampal synaptic plasticity. The objectives of this study were to investigate endogenous rhythms of catalase (CAT) and glutathione peroxidase (GPx) expression and activity, as well as CREB1 mRNA, in the rat hippocampus, and to evaluate to which extent the vitamin A deficiency could affect those temporal patterns. Rats from control and vitamin A-deficient (VAD) groups received a diet containing 4000 IU of vitamin A/kg diet, or the same diet devoid of vitamin A, respectively, during 3 months. Rats were maintained under 12-hour-dark conditions, during 10 days before the sacrifice. Circadian rhythms of CAT, GPx, RXRγ, and CREB1 mRNA levels were determined by reverse transcriptrase polymerase chain reaction in hippocampus samples isolated every 4 hours during a 24-hour period. CAT and GPx enzymatic activities were also determined by kinetic assays. Regulatory regions of clock and antioxidant enzymes genes were scanned for E-box, RXRE, and CRE sites. E-box, RXRE, and CRE sites were found on regulatory regions of GPx and CAT genes, which display a circadian expression in the rat hippocampus. VAD phase shifted CAT, GPx, and RXRγ endogenous rhythms without affecting circadian expression of CREB1. CAT and GPx expression and enzymatic activity are circadian in the rat hippocampus. The VAD affected the temporal patterns antioxidant genes expression, probably by altering circadian rhythms of its RXR receptors and clock factors; thus, it would impair the temporal orchestration of hippocampal daily cognitive performance.

  4. Assessing two different peroxidases´ potential for application in recalcitrant organic compound bioremediation

    Directory of Open Access Journals (Sweden)

    Nelson Caicedo

    2001-07-01

    Full Text Available This work shows the promising future presented by the following enzymes: Chloroperoxidase (CPO from Caldariomyces fumago and royal palm peroxidase (Roystonea regia, PPR. These peroxidases were obtained from different sources (microbial and vegetable and used as biocatalysts for applicating them in bioremediation of recalcitrant organic compounds. Each one of the enzymes' peroxidase catalytic activity was evaluated in organic phase systems, using different model compounds such as: PAHs (pyrene and anthracene, organic-nitrogenated compounds (diphenylamine, monoaromatic phenolic molecules (guayacol and dyes (methyl orange and ABTS. The reaction systems were composed of mono-phase water mixtures and organic miscible solvent (methanol, ethanol, isopropanol, acetonitrile, tetrahydrofuran, dimethyl sulfoxide and dimethyl formamide, on which both peroxidases' catalytic activity was evaluated. The two enzymes' catalytic activity was observed on the evaluated substrates in most of these assays. However, PPR did not show biocatalytic oxidation for methyl orange dye and some PAHs. This enzyme did show the best tolerance to the evaluated solvents. Its catalytic activity was appreciably enhanced when low hydrophobic solvents were used. The kcat was calculated from this experimental data (as kinetic parameter leading to each enzyme's biocatalytic performance on substrates being compared.

  5. A catalytic approach to estimate the redox potential of heme-peroxidases

    International Nuclear Information System (INIS)

    Ayala, Marcela; Roman, Rosa; Vazquez-Duhalt, Rafael

    2007-01-01

    The redox potential of heme-peroxidases varies according to a combination of structural components within the active site and its vicinities. For each peroxidase, this redox potential imposes a thermodynamic threshold to the range of oxidizable substrates. However, the instability of enzymatic intermediates during the catalytic cycle precludes the use of direct voltammetry to measure the redox potential of most peroxidases. Here we describe a novel approach to estimate the redox potential of peroxidases, which directly depends on the catalytic performance of the activated enzyme. Selected p-substituted phenols are used as substrates for the estimations. The results obtained with this catalytic approach correlate well with the oxidative capacity predicted by the redox potential of the Fe(III)/Fe(II) couple

  6. Spatial distribution of enzyme activities in the rhizosphere

    Science.gov (United States)

    Razavi, Bahar S.; Zarebanadkouki, Mohsen; Blagodatskaya, Evgenia; Kuzyakov, Yakov

    2015-04-01

    The rhizosphere, the tiny zone of soil surrounding roots, certainly represents one of the most dynamic habitat and interfaces on Earth. Activities of enzymes produced by both plant roots and microbes are the primary biological drivers of organic matter decomposition and nutrient cycling. That is why there is an urgent need in spatially explicit methods for the determination of the rhizosphere extension and enzyme distribution. Recently, zymography as a new technique based on diffusion of enzymes through the 1 mm gel plate for analysis has been introduced (Spohn & Kuzyakov, 2013). We developed the zymography technique to visualize the enzyme activities with a higher spatial resolution. For the first time, we aimed at quantitative imaging of enzyme activities as a function of distance from the root tip and the root surface in the soil. We visualized the two dimensional distribution of the activity of three enzymes: β-glucosidase, phosphatase and leucine amino peptidase in the rhizosphere of maize using fluorogenically labelled substrates. Spatial-resolution of fluorescent images was improved by direct application of a substrate saturated membrane to the soil-root system. The newly-developed direct zymography visualized heterogeneity of enzyme activities along the roots. The activity of all enzymes was the highest at the apical parts of individual roots. Across the roots, the enzyme activities were higher at immediate vicinity of the roots (1.5 mm) and gradually decreased towards the bulk soil. Spatial patterns of enzyme activities as a function of distance from the root surface were enzyme specific, with highest extension for phosphatase. We conclude that improved zymography is promising in situ technique to analyze, visualize and quantify spatial distribution of enzyme activities in the rhizosphere hotspots. References Spohn, M., Kuzyakov, Y., 2013. Phosphorus mineralization can be driven by microbial need for carbon. Soil Biology & Biochemistry 61: 69-75

  7. Enzyme activity and kinetics in substrate-amended river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Duddridge, J E; Wainwright, M

    1982-01-01

    In determining the effects of heavy metals in microbial activity and litter degradation in river sediments, one approach is to determine the effects of these pollutants on sediment enzyme activity and synthesis. Methods to assay amylase, cellulase and urease activity in diverse river sediments are reported. Enzyme activity was low in non-amended sediments, but increased markedly when the appropriate substrate was added, paralleling both athropogenic and natural amendment. Linear relationships between enzyme activity, length of incubation, sample size and substrate concentration were established. Sediment enzyme activity generally obeyed Michaelis-Menton kinetics, but of the three enzymes, urease gave least significant correlation coefficients when the data for substrate concentration versus activity was applied to the Eadie-Hofstee transformation of the Michaelis-Menten equation. K/sub m/ and V/sub max/ for amylase, cellulase and urease in sediments are reported. (JMT)

  8. Improving enzymatic activities and thermostability of a tri-functional enzyme with SOD, catalase and cell-permeable activities.

    Science.gov (United States)

    Luangwattananun, Piriya; Eiamphungporn, Warawan; Songtawee, Napat; Bülow, Leif; Isarankura Na Ayudhya, Chartchalerm; Prachayasittikul, Virapong; Yainoy, Sakda

    2017-04-10

    Synergistic action of major antioxidant enzymes, e.g., superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) is known to be more effective than the action of any single enzyme. Recently, we have engineered a tri-functional enzyme, 6His-MnSOD-TAT/CAT-MnSOD (M-TAT/CM), with SOD, CAT and cell-permeable activities. The protein actively internalized into the cells and showed superior protection against oxidative stress-induced cell death over native enzymes fused with TAT. To improve its molecular size, enzymatic activity and stability, in this study, MnSOD portions of the engineered protein were replaced by CuZnSOD, which is the smallest and the most heat resistant SOD isoform. The newly engineered protein, CAT-CuZnSOD/6His-CuZnSOD-TAT (CS/S-TAT), had a 42% reduction in molecular size and an increase in SOD and CAT activities by 22% and 99%, respectively. After incubation at 70°C for 10min, the CS/S-TAT retained residual SOD activity up to 54% while SOD activity of the M-TAT/CM was completely abolished. Moreover, the protein exhibited a 5-fold improvement in half-life at 70°C. Thus, this work provides insights into the design and synthesis of a smaller but much more stable multifunctional antioxidant enzyme with ability to enter mammalian cells for further application as protective/therapeutic agent against oxidative stress-related conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Thermodynamic Activity-Based Progress Curve Analysis in Enzyme Kinetics.

    Science.gov (United States)

    Pleiss, Jürgen

    2018-03-01

    Macrokinetic Michaelis-Menten models based on thermodynamic activity provide insights into enzyme kinetics because they separate substrate-enzyme from substrate-solvent interactions. Kinetic parameters are estimated from experimental progress curves of enzyme-catalyzed reactions. Three pitfalls are discussed: deviations between thermodynamic and concentration-based models, product effects on the substrate activity coefficient, and product inhibition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Nanodiamonds as pH-switchable oxidation and reduction catalysts with enzyme-like activities for immunoassay and antioxidant applications.

    Science.gov (United States)

    Chen, T M; Tian, X M; Huang, L; Xiao, J; Yang, G W

    2017-10-19

    Nanodiamonds (NDs) have recently become a focus of interest from the viewpoints of both science and technology. Their intriguing properties make them suitable as biologically active substrates, in biosensor applications as well as diagnostic and therapeutic biomedical imaging probes. Here, we demonstrate that NDs, as oxidation and reduction catalysts, possess intrinsic enzyme mimetic properties of oxidase, peroxidase and catalase, and these behaviors can be switched by modulating the pH value. NDs not only catalyze the reduction of oxygen (O 2 ) and hydrogen peroxide (H 2 O 2 ) at acidic pH, but also catalyze the dismutation decomposition of H 2 O 2 to produce O 2 at alkaline pH. It was proposed that the molecular mechanism of their peroxidase-like activity is electron-transfer acceleration, the source of which is likely derived from oxygen containing functional groups on their surface. Based on the color reaction, a nanodiamond-based enzyme linked immunosorbent assay (ELISA) was established for the detection of immunoglobulin G (IgG). Surprisingly, NDs display an excellent antioxidant activity due to the protective effect against H 2 O 2 -induced cellular oxidative damage. These findings make NDs a promising enzyme mimetic candidate and expand their applications in biocatalysis, bioassays and nano-biomedicine.

  11. Microbial Enzyme Activity and Carbon Cycling in Grassland Soil Fractions

    Science.gov (United States)

    Allison, S. D.; Jastrow, J. D.

    2004-12-01

    Extracellular enzymes are necessary to degrade complex organic compounds present in soils. Using physical fractionation procedures, we tested whether old soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates, microaggregates, and the clay fraction, which contains carbon with a mean residence time of ~200 years. The activities of two cellulose-degrading enzymes and a chitin-degrading enzyme were 2-10 times greater in organic matter fractions than in bulk soil, consistent with the rapid turnover of these fractions. Polyphenol oxidase activity was 3 times greater in the clay fraction than in the bulk soil, despite very slow carbon turnover in this fraction. Changes in enzyme activity across the restoration chronosequence were small once adjusted for increases in soil carbon concentration, although polyphenol oxidase activity per unit carbon declined by 50% in native prairie versus cultivated soil. These results are consistent with a `two-pool' model of enzyme and carbon turnover in grassland soils. In light organic matter fractions, enzyme production and carbon turnover both occur rapidly. However, in mineral-dominated fractions, both enzymes and their carbon substrates are immobilized on mineral surfaces, leading to slow turnover. Soil carbon accumulation in the clay fraction and across the prairie restoration chronosequence probably reflects increasing physical isolation of enzymes and substrates on the molecular scale, rather than the micron to millimeter scale.

  12. Oxidative status, in vitro iron-induced lipid oxidation and superoxide dismutase, catalase and glutathione peroxidase activities in rhea meat.

    Science.gov (United States)

    Terevinto, A; Ramos, A; Castroman, G; Cabrera, M C; Saadoun, A

    2010-04-01

    Rhea (Rhea americana) muscles Obturatorius medialis (OM) Iliotibialis lateralis (IL) and Iliofibularis (I), obtained from farmed animals, were evaluated regarding their oxidative/antioxidant status. The mean level of thiobarbituric acid reactive substances (TBARS) expressed as malonaldehyde (MDA) content was of 0.84 mg MDA/kg wet tissue for the three muscles. TBARS level was significantly higher in IL than OM and I, with the two latter showing similar levels. The mean level of carbonyl proteins expressed as dinitrophenylhydrazine (DNPH) was 1.59 nmol DNPH mg(-1). Carbonyl protein levels were significantly different (POM>I). Iron-induced TBARS generation was not significantly different between the three muscles at any time, nor for each muscle during the 5 h of the experiment. Superoxide dismutase activity in IL muscle was significantly higher (P<0.05) than in I muscle. However, the difference between IL and OM muscles was not significant. The differences between the three muscles became not significant when the results were expressed by mg of protein contained in the extract, instead by g of wet tissue. No differences were found for catalase (micromol of discomposed H(2)O(2) min(-1) g(-1) wet tissue or by mg of protein contained in the extract) and glutathione peroxidase (micromol ol of oxidized NADPH min(-1) g(-1) of wet tissue or by mg of protein contained in the extract) activities between the three muscles. 2009 Elsevier Ltd. All rights reserved.

  13. Correlation between the potency of flavonoids for cytochrome c reduction and inhibition of cardiolipin-induced peroxidase activity.

    Science.gov (United States)

    Lagoa, Ricardo; Samhan-Arias, Alejandro K; Gutierrez-Merino, Carlos

    2017-05-06

    There are large differences between flavonoids to protect against apoptosis, a process in which cytochrome c (Cyt c) plays a key role. In this work, we show that 7 of 13 flavonoids studied have a capacity to reduce Cyt c similar or higher than ascorbate, the flavonols quercetin, kaempferol and myricetin, flavanol epigallocatechin-gallate, anthocyanidins cyanidin and malvidin, and the flavone luteolin. In contrast, the kaempferol 3(O)- and 3,4'(O)-methylated forms, the flavanone naringenin, and also apigenin and chrysin, had a negligible reducing capacity. Equilibrium dialysis and quenching of 1,6-diphenyl-1,3,5-hexatriene fluorescence experiments showed that flavonoids did not interfere with Cyt c binding to cardiolipin (CL)/phosphatidylcholine (PC) vesicles. However, the CL-induced loss of Cyt c Soret band intensity was largely attenuated by flavonoids, pointing out a stabilizing action against Cyt c unfolding in the complex. Moreover, flavonoids that behave as Cyt c reductants also inhibited the pro-apoptotic CL-induced peroxidase activity of Cyt c, indicating that modulation of Cyt c signaling are probable mechanisms behind the protective biological activities of flavonoids. © 2016 BioFactors, 43(3):451-468, 2017. © 2017 International Union of Biochemistry and Molecular Biology.

  14. A novel amperometric alcohol biosensor developed in a 3rd generation bioelectrode platform using peroxidase coupled ferrocene activated alcohol oxidase as biorecognition system.

    Science.gov (United States)

    Chinnadayyala, Somasekhar R; Kakoti, Ankana; Santhosh, Mallesh; Goswami, Pranab

    2014-05-15

    Alcohol oxidase (AOx) with a two-fold increase in efficiency (Kcat/Km) was achieved by physical entrapment of the activator ferrocene in the protein matrix through a simple microwave based partial unfolding technique and was used to develop a 3rd generation biosensor for improved detection of alcohol in liquid samples. The ferrocene molecules were stably entrapped in the AOx protein matrix in a molar ratio of ~3:1 through electrostatic interaction with the Trp residues involved in the functional activity of the enzyme as demonstrated by advanced analytical techniques. The sensor was fabricated by immobilizing ferrocene entrapped alcohol oxidase (FcAOx) and sol-gel chitosan film coated horseradish peroxidase (HRP) on a multi-walled carbon nanotube (MWCNT) modified glassy carbon electrode through layer-by-layer technique. The bioelectrode reactions involved the formation of H2O2 by FcAOx biocatalysis of substrate alcohol followed by HRP-catalyzed reduction of the liberated H2O2 through MWCNT supported direct electron transfer mechanism. The amperometric biosensor exhibited a linear response to alcohol in the range of 5.0 × 10(-6) to 30 × 10(-4)mol L(-1) with a detection limit of 2.3 × 10(-6) mol L(-1), and a sensitivity of 150 µA mM(-1) cm(-2). The biosensor response was steady for 28 successive measurements completed in a period of 5h and retained ~90% of the original response even after four weeks when stored at 4 °C. The biosensor was successfully applied for the determination of alcohol in commercial samples and its performance was validated by comparing with the data obtained by GC analyses of the samples. © 2013 Published by Elsevier B.V.

  15. Effects of de-icing salt on soil enzyme activity

    Energy Technology Data Exchange (ETDEWEB)

    Guentner, M; Wilke, B M

    1983-01-01

    Effects of de-icing salt on dehydrogenase, urease, alkalinephosphatase and arylsulfatase activity of O/sub L/- and A/sub h/-horizons of a moder and a mull soil were investigated using a field experiment. Additions of 2.5 kg m/sup -2/ and 5.0 kg m/sup -2/ of de-icing salt reduced activities of most enzymes within four weeks. Eleven months after salt addition there was nearly no reduction of enzyme activity to be measured on salt treated soils. The percentage of reduced enzyme activity was generally higher in the moder soil. It was concluded that reductions of enzyme activity were due to decreases of microbial activity and not to inactivation of enzymes.

  16. 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 ...

  17. Decolorization of direct dyes using peroxidase from raphanus sativus (F04 SL)

    International Nuclear Information System (INIS)

    Bhatti, H.N.; Kalsoom, U.; Habib, A.

    2012-01-01

    An acidic peroxidase was isolated and partially purified from Raphanus sativus. The purified enzyme was characterized in terms of kinetics and thermodynamic aspects. Finally the enzyme was assessed to see its potential for decolorization of direct dyes. The specific activity of Raphanus sativus peroxidase increased from 44.77 to 65.20 U/mg of protein using 80 % ammonium sulphate precipitation. The optimum pH and temperature of the enzyme was 4 and 55 deg. C respectively. The activation energy of Raphanus sativus peroxidase was 25.44 kJ/mol and average value of Km was 0.25 mM. The activation energy of thermal denaturation of Raphanus sativus peroxidase was 17.79 kJ/mol. It was observed that with an increase in temperature, there was decrease in a half life and enthalpy, which showed that the enzyme was unstable at higher temperature. A maximum decolorization of 97 and 77 % was observed for Solar Blue A and Solar Flavine 5G at pH 4 and temperature 50 deg. C respectively. It was observed that % decolorization of both the dyes increased with an increase in enzyme units and incubation time. H/sub 2/O/sub 2/ dose of 0.8 mM for Solar Blue A and 0.7 mM for Solar Flavine 5G was sufficient for the maximum dye degradation. (author)

  18. Ultrasound in Enzyme Activation and Inactivation

    Science.gov (United States)

    Mawson, Raymond; Gamage, Mala; Terefe, Netsanet Shiferaw; Knoerzer, Kai

    As discussed in previous chapters, most effects due to ultrasound arise from cavitation events, in particular, collapsing cavitation bubbles. These collapsing bubbles generate very high localized temperatures and pressure shockwaves along with micro-streaming that is associated with high shear forces. These effects can be used to accelerate the transport of substrates and reaction products to and from enzymes, and to enhance mass transfer in enzyme reactor systems, and thus improve efficiency. However, the high velocity streaming, together with the formation of hydroxy radicals and heat generation during collapsing of bubbles, may also potentially affect the biocatalyst stability, and this can be a limiting factor in combined ultrasound/enzymatic applications. Typically, enzymes can be readily denatured by slight changes in environmental conditions, including temperature, pressure, shear stress, pH and ionic strength.

  19. Keratocyte apoptosis and corneal antioxidant enzyme activities after refractive corneal surgery.

    Science.gov (United States)

    Bilgihan, K; Bilgihan, A; Adiguzel, U; Sezer, C; Yis, O; Akyol, G; Hasanreisoglu, B

    2002-01-01

    Refractive corneal surgery induces keratocyte apoptosis and generates reactive oxygen radicals (ROS) in the cornea. The purpose of the present study is to evaluate the correlation between keratocyte apoptosis and corneal antioxidant enzyme activities after different refractive surgical procedures in rabbits. Rabbits were divided into six groups. All groups were compared with the control group (Group 1), after epithelial scraping (Group 2), epithelial scrape and photorefractive keratectomy (PRK) (traditional PRK: Group 3), transepithelial PRK (Group 4), creation of a corneal flap with microkeratome (Group 5) and laser-assisted in situ keratomileusis (LASIK, Group 6). Terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay (to detect DNA fragmentation in situ) and light microscopy were used to detect apoptosis in rabbit eyes. Glutathione peroxidase (Gpx) and superoxide dismutase (SOD) activities of the corneal tissues were measured with spectrophotometric methods. Corneal Gpx and SOD activities decreased significantly in all groups when compared with the control group (P<0.05) and groups 2, 3 and 6 showed a significantly higher amount of keratocyte apoptosis (P<0.05). Not only a negative correlation was observed between corneal SOD activity and keratocyte apoptosis (cc: -0.3648) but Gpx activity also showed negative correlation with keratocyte apoptosis (cc: -0.3587). The present study illustrates the negative correlation between keratocyte apoptosis and corneal antioxidant enzyme activities. This finding suggests that ROS may be partly responsible for keratocyte apoptosis after refractive surgery.

  20. Immobilized enzyme reactor chromatography: Optimization of protein retention and enzyme activity in monolithic silica stationary phases

    International Nuclear Information System (INIS)

    Besanger, Travis R.; Hodgson, Richard J.; Green, James R.A.; Brennan, John D.

    2006-01-01

    Our group recently reported on the application of protein-doped monolithic silica columns for immobilized enzyme reactor chromatography, which allowed screening of enzyme inhibitors present in mixtures using mass spectrometry for detection. The enzyme was immobilized by entrapment within a bimodal meso/macroporous silica material prepared by a biocompatible sol-gel processing route. While such columns proved to be useful for applications such as screening of protein-ligand interactions, significant amounts of entrapped proteins leached from the columns owing to the high proportion of macropores within the materials. Herein, we describe a detailed study of factors affecting the morphology of protein-doped bioaffinity columns and demonstrate that specific pH values and concentrations of poly(ethylene glycol) can be used to prepare essentially mesoporous columns that retain over 80% of initially loaded enzyme in an active and accessible form and yet still retain sufficient porosity to allow pressure-driven flow in the low μL/min range. Using the enzyme γ-glutamyl transpeptidase (γ-GT), we further evaluated the catalytic constants of the enzyme entrapped in capillary columns with different silica morphologies as a function of flowrate and backpressure using the enzyme reactor assay mode. It was found that the apparent activity of the enzyme was highest in mesoporous columns that retained high levels of enzyme. In such columns, enzyme activity increased by ∼2-fold with increases in both flowrate (from 250 to 1000 nL/min) and backpressure generated (from 500 to 2100 psi) during the chromatographic activity assay owing to increases in k cat and decreases in K M , switching from diffusion controlled to reaction controlled conditions at ca. 2000 psi. These results suggest that columns with minimal macropore volumes (<5%) are advantageous for the entrapment of soluble proteins for bioaffinity and bioreactor chromatography

  1. Modification of polymer surfaces to enhance enzyme activity and stability

    DEFF Research Database (Denmark)

    Hoffmann, Christian

    Enzyme immobilization is an important concept for the development of improved biocatalytic processes, primarily through facilitated separation procedures. However, enzyme immobilization usually comes at a price of reduced biocatalytic activity. For this reason, different immobilization methods have...... already been developed, combining the same goal to improve enzyme activity, stability and selectivity. Polymer materials have shown, due to their easy processibility and versatile properties, high potential as enzyme support. However, in order to achieve improved enzyme performance, the combination...... on their tailored surface modification in order to obtain improved enzyme-support systems. Firstly, an off-stoichiometric thiol-ene (OSTE) thermosetting material was used for the development of a screening platform allowing the investigation of micro-environmental effects and their impact on the activity...

  2. Isolation of a tyrosine-activating enzyme from baker's yeast

    NARCIS (Netherlands)

    Ven, A.M. van de; Koningsberger, V.V.; Overbeek, J.Th.G.

    1958-01-01

    The extracts of ether-CO2-frozen baker's yeast contain enzymes that catalyze the ATP-linked amino acid activation by way of pyrophosphate elimination. From the extract a tyrosine-activating enzyme could be isolated, which, judging from ultracentrifugation and electrophoretic data, was about 70% pure

  3. A Simple and Accurate Method for Measuring Enzyme Activity.

    Science.gov (United States)

    Yip, Din-Yan

    1997-01-01

    Presents methods commonly used for investigating enzyme activity using catalase and presents a new method for measuring catalase activity that is more reliable and accurate. Provides results that are readily reproduced and quantified. Can also be used for investigations of enzyme properties such as the effects of temperature, pH, inhibitors,…

  4. Arabidopsis thaliana peroxidase N

    DEFF Research Database (Denmark)

    Mirza, Osman Asghar; Henriksen, A; Ostergaard, L

    2000-01-01

    The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C...

  5. Effect Of Heavy Metals Stress On Enzyme Activities And Chlorophyll Content Of Pea (Pisum Sativum) And Tomato Plants

    International Nuclear Information System (INIS)

    Ahmed, B.M.; El Maghrabi, G.; Hashem, M.F.

    2013-01-01

    The effects of heavy metal stress on the chlorophyll in addition to catalase and peroxidase activities were studied in the leaves and roots of tomato and pea plants. Four groups were studied; the control group and other three groups treated with heavy metals. Group 1HM was treated with 1.0 mg CuSO 4 /l + 0.2 mg CdSO 4 /l + 0.1 mg ZnNO 3 /l every 10 days while in group 5 HM and group 10 HM, the doses were 5 and 10 folds the 1 HM, respectively. Leaves and roots of control and heavy metal-stressed plants were harvested after 10 weeks for chlorophyll determination. The chlorophyll content, especially chlo. b, was significantly decreased with the increase in heavy metals stress in both plants. In leaves of heavy metal-stressed plants, the peroxidase level in different stress levels was increased with increasing stress levels in tomato and pea while catalase was unchanged in leaves of tomato in comparison with the control. The activities of catalase and peroxidase in roots of heavy metal-stressed plants were increased in group 5 HM then decreased in case of group 10 HM. The increase in enzyme activities demonstrated that tomato is more tolerant to heavy metals than pea

  6. Thermodynamic activity-based intrinsic enzyme kinetic sheds light on enzyme-solvent interactions.

    Science.gov (United States)

    Grosch, Jan-Hendrik; Wagner, David; Nistelkas, Vasilios; Spieß, Antje C

    2017-01-01

    The reaction medium has major impact on biocatalytic reaction systems and on their economic significance. To allow for tailored medium engineering, thermodynamic phenomena, intrinsic enzyme kinetics, and enzyme-solvent interactions have to be discriminated. To this end, enzyme reaction kinetic modeling was coupled with thermodynamic calculations based on investigations of the alcohol dehydrogenase from Lactobacillus brevis (LbADH) in monophasic water/methyl tert-butyl ether (MTBE) mixtures as a model solvent. Substrate concentrations and substrate thermodynamic activities were varied separately to identify the individual thermodynamic and kinetic effects on the enzyme activity. Microkinetic parameters based on concentration and thermodynamic activity were derived to successfully identify a positive effect of MTBE on the availability of the substrate to the enzyme, but a negative effect on the enzyme performance. In conclusion, thermodynamic activity-based kinetic modeling might be a suitable tool to initially curtail the type of enzyme-solvent interactions and thus, a powerful first step to potentially understand the phenomena that occur in nonconventional media in more detail. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:96-103, 2017. © 2016 American Institute of Chemical Engineers.

  7. Toxic action of zinc on growth and enzyme activities of rice Oryza sativa L. seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Nag, P.; Nag, P.; Paul, A.K.; Mukherji, S.

    1984-01-01

    This paper provides information on the effects of toxic concentrations of zinc sulfate (ZnSO/sub 4/.7H/sub 2/O) on the growth and metabolism of rice Oryza sativa L. seedlings. Root growth inhibition was always more pronounced than was shoot growth inhibition. Root growth was completely inhibited at 40 m M concentration, whereas the magnitude of reduction of shoot length was only 56% at this concentration. Gibberellic acid (GA/sub 3/) was partially capable of relieving zinc inhibition. The activities of peroxidase, IAA oxidase and ascorbic acid oxidase of seedlings increased in response to zinc addition, whereas catalase and IAA synthetase decreased. All the hydrolyzing enzymes, viz., ..cap alpha..-amylase and phytase of endosperm together with RNase and ATPase of the embryo, showed distinct inhibition from the control, the exception being endosperm RNase which was stimulated under zinc treatment. 50 references, 6 figures.

  8. Synthesis, structure, and glutathione peroxidase-like activity of amino acid containing ebselen analogues and diaryl diselenides.

    Science.gov (United States)

    Selvakumar, Karuthapandi; Shah, Poonam; Singh, Harkesh B; Butcher, Ray J

    2011-11-04

    The synthesis of some ebselen analogues and diaryl diselenides, which have amino acid functions as an intramolecularly coordinating group (Se···O) has been achieved by the DCC coupling procedure. The reaction of 2,2'-diselanediylbis(5-tert-butylisophthalic acid) or the activated ester tetrakis(2,5-dioxopyrrolidin-1-yl) 2,2'-diselanediylbis(5-tert-butylisophthalate) with different C-protected amino acids (Gly, L-Phe, L-Ala, and L-Trp) afforded the corresponding ebselen analogues. The used precursor diselenides have been found to undergo facile intramolecular cyclization during the amide bond formation reaction. In contrast, the DCC coupling of 2,2'-diselanediyldibenzoic acid with C-protected amino acids (Gly, L/D-Ala and L-Phe) affords the corresponding amide derivatives and not the ebselen analogues. Some of the representative compounds have been structurally characterized by single-crystal X-ray crystallography. The glutathione peroxidase (GPx)-like activities of the ebselen analogues and the diaryl diselenides have been evaluated by using the coupled reductase assay method. Intramolecularly stabilized ebselen analogues show slightly higher maximal velocity (V(max)) than ebselen. However, they do not show any GPx-like activity at low GSH concentrations at which ebselen and related diselenides are active. This could be attributed to the peroxide-mediated intramolecular cyclization of the corresponding selenenyl sulfide and diaryl diselenide intermediates generated during the catalytic cycle. Interestingly, the diaryl diselenides with alanine (L,L or D,D) amide moieties showed excellent catalytic efficiency (k(cat)/K(M)) with low K(M) values in comparison to the other compounds. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Site- and horizon-specific patterns of microbial community structure and enzyme activities in permafrost-affected soils of Greenland

    DEFF Research Database (Denmark)

    Gittel, Antje; Barta, Jiri; Kohoutova, Iva

    2014-01-01

    topsoils”), resulting from a decrease in fungal abundance compared to recent (“unburied”) topsoils. Actinobacteria (in particular Intrasporangiaceae) accounted for a major fraction of the microbial community in buried topsoils, but were only of minor abundance in all other soil horizons. It was indicated...... that the distribution pattern of Actinobacteria and a variety of other bacterial classes was related to the activity of phenol oxidases and peroxidases supporting the hypothesis that bacteria might resume the role of fungi in oxidative enzyme production and degradation of phenolic and other complex substrates...

  10. Association between Antioxidant Enzyme Activities and Enterovirus-Infected Type 1 Diabetic Children.

    Science.gov (United States)

    Abdel-Moneim, Adel; El-Senousy, Waled M; Abdel-Latif, Mahmoud; Khalil, Rehab G

    2018-01-01

    To examine the effect of infection with Enterovirus (EV) in children with type 1 diabetes (T1D) on the activities of serum antioxidant enzymes in diabetic and nondiabetic controls. Three hundred and eighty-two diabetic and 100 nondiabetic children were tested for EV RNA using reverse transcriptase (RT)-PCR. The activities of serum superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were also estimated in diabetic patients infected with EV (T1D-EV+), those not infected with EV (T1D-EV-), and in nondiabetic controls. The frequency of EV was higher in diabetic children (100/382; 26.2%) than in healthy controls (0/100). Levels of fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c) and C-reactive protein (CRP) were significantly higher but C-peptide was significantly lower in diabetic children than in controls. CRP levels were higher in the T1D-EV+ group than in the T1D-EV- group, and higher in all diabetic children than in nondiabetic controls. The activities of the antioxidant enzymes GPx, SOD, and CAT decreased significantly in diabetic children compared to in controls. Moreover, the activities of the enzymes tested were significantly reduced in the T1D-EV+ group compared to in the T1D-EV- group. Our data indicate that EV infection correlated with a decrease in the activity of antioxidant enzymes in the T1D-EV+ group compared to in the T1D-EV- group; this may contribute to β cell damage and increased inflammation. © 2018 The Author(s) Published by S. Karger AG, Basel.

  11. Physiological responses of Brassica napus to fulvic acid under water stress: Chlorophyll a fluorescence and antioxidant enzyme activity

    Directory of Open Access Journals (Sweden)

    Ramin Lotfi

    2015-10-01

    Full Text Available The ameliorative effect of fulvic acid (0, 300, and 600 mg L− 1 on photosystem II and antioxidant enzyme activity of the rapeseed (Brassica napus L. plant under water stress (60, 100, and 140 mm evaporation from class A pan was studied using split plots in a randomized complete block design with three replications. Results indicated that application of fulvic acid (FA improved the maximum quantum efficiency of PSII (Fv/Fm and performance index (PI of plants under both well-watered and limited-water conditions. The time span from Fo to Fm and the energy necessary for the closure of all reaction centers was significantly increased, but the size of the plastoquinone pool was reduced with increasing water stress levels. Plants treated with FA had higher peroxidase and catalase activities under all irrigation conditions. Activities of ascorbate peroxidase and superoxide dismutase in plants increased with increasing water stress. Malondialdehyde increased under severe water stress, but application of FA significantly decreased lipid peroxidation. Production of reactive oxygen species (ROS is a common phenomenon in plants under stress. Under this condition, the balance between the production of ROS and the quenching activity of antioxidants is upset, often resulting in oxidative damage. In this study, application of FA significantly increased fluorescence of chlorophyll a, inhibiting ROS production and enhancing antioxidant enzymes activity that destroyed ROS. Thus, ROS in plant cells was reduced under water stress by application of FA and consequently lipid peroxidation was reduced.

  12. EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS

    DEFF Research Database (Denmark)

    De Fine Licht, Henrik H; Schiøtt, Morten; Mueller, Ulrich G

    2010-01-01

    an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across...... the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens...... are targeted primarily towards partial degradation of plant cell walls, reflecting a plesiomorphic state of non-domesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major...

  13. Leishmania mexicana amazonensis: heterogeneity in 5-nucleotidase and peroxidase activities of mononuclear phagocytes during in vivo and in vitro infection Leishmania mexicana amazonensis: heterogeneidade da 5’-Nucleotidase e da peroxidase em fagócitos mononucleares durante infecção in vivo e in vitro

    Directory of Open Access Journals (Sweden)

    Suzana Côrte-Real

    1988-03-01

    Full Text Available The degree of maturation of cells of the Mononuclear Phagocyte System (MPS, during in vivo and in vitro infection by Leishmania mexicana amazonenesis, was evaluated in this study. The macrophages' differentiation was assayed by cytochemical characterization at the ultrastrctural level, using two well-established markers: 5'-nucleotidase enzyme activity, for revealing the mature cells, and the peroxidase activity present in the cell granules to demonstrate immature mononuclear phagocytes. only a few mcrophages, demonstrating 5'-nucleotidase positive reaction in both the plasma membrane and within their cytoplasmic vesicles, were found scattered in the chronic inflammation at the L. m. amazonensis lesions in albino mice. However, by the peroxidase activity analysis, we were also able to demonstrate the presence of immature MPS cells, which predominate, together with parasitized vacuolated macrophages, in chronic lesions induced in this systemby L. m. amazonensis. The implications of these results on the pathogenesis of murine cutaneous leishmaniasis are discussed.Um estudo sobre o grau de maturação das células do Sistema Fagocítico Mononuclear foi realizado durante a infecção in vivo e in vitro com a Leishmania mexicana amazonensis. A caracterização da diferenciação das células fagocíticas foi obtida com a localização ultraestrutural de dois marcadores enzimáticos bam conhecidos: a enzima 5'-Nucleotidase marcadora de membrana plasmática de células maduras e a enzima peroxidase, presente em grânulos, marcadora de células imaturas. A atividade da enzima 5'-Nucleotidase foi encontrada apenas em alguns macrófagos, presentes no foco inflamatório, em projeções da membrana plasmática e em algumas vesículas citoplasmáticas. Macrófagos peritoneais de camundongo apresentaram a mesma reatividade para este marcador. Contudo a análise da atividade peroxidásica demonstrou a predominância da presença de fagócitos mononucleares

  14. Influence of 2. 45 GHz microwave radiation on enzyme activity

    Energy Technology Data Exchange (ETDEWEB)

    Galvin, M J; Parks, D L; McRee, D I

    1981-05-01

    The in vitro activity of acetylcholinesterase and creatine phosphokinase was determined during in vitro exposure to 2.45 GHz microwave radiation. The enzyme activities were examined during exposure to microwave radiation at specific absorption rates (SAR) of 1, 10, 50, and 100 mW/g. These specific absorption rates had no effect on the activity of either enzyme when the temperature of the control and exposed samples were similar. These data demonstrate that the activity of these two enzymes is not affected by microwave radiation at the SARs and frequency employed in this study.

  15. Continuous microwave pasteurization of a vegetable smoothie improves its physical quality and hinders detrimental enzyme activity.

    Science.gov (United States)

    Arjmandi, Mitra; Otón, Mariano; Artés, Francisco; Artés-Hernández, Francisco; Gómez, Perla A; Aguayo, Encarna

    2017-01-01

    The effect of a pasteurization treatment at 90 ± 2 ℃ for 35 s provided by continuous microwave under different doses (low power/long time and high power/short time) or conventional pasteurization on the quality of orange-colored smoothies and their changes throughout 45 days of storage at 5 ℃ was investigated. A better color retention of the microwave pasteurization- treated smoothie using high power/short time than in conventionally processed sample was evidenced by the stability of the hue angle. The continuous microwave heating increased the viscosity of the smoothie more than the conventional pasteurization in comparison with non-treated samples. Lower residual enzyme activities from peroxidase, pectin methylesterase and polygalacturonase were obtained under microwave heating, specifically due to the use of higher power/shorter time. For this kind of smoothie, polygalacturonase was the more thermo-resistant enzyme and could be used as an indicator of pasteurization efficiency. The use of a continuous semi-industrial microwave using higher power and shorter time, such as 1600 W/206 s and 3600 W/93 s, resulted in better quality smoothies and greater enzyme reduction than conventional thermal treatment. © The Author(s) 2016.

  16. Comparative evaluation of oxidative enzyme activities during adventitious rooting in the cuttings of grapevine rootstocks.

    Science.gov (United States)

    Kose, Cafer; Erdal, Serkan; Kaya, Ozkan; Atici, Okkeş

    2011-03-15

    This study investigated changes in peroxidase (POX) and polyphenol oxidase (PPO) activities through adventitious rooting in hardwood cuttings of grapevine rootstocks. Three grapevine rootstocks with different propensity to produce adventitious roots were selected: recalcitrant (Ramsey), non-recalcitrant (Rupestris du Lot) and intermediate (99R) cultivars. The averages of root number at 65 days were 96 in Lot, 76 in 99R and 30 in Ramsey. Both enzyme activities characteristically increased before adventitious rooting, regardless of rooting ability of the rootstocks, and then decreased. POX activity increased in Ramsey cuttings at 22 days, in Lot and 99R cuttings at 14 days after planting, and then decreased gradually until 51 days. The highest POX activity was determined in Ramsey rootstock with the highest rooting ability and the lowest activity was determined in the rootstocks with the lowest rooting ability. PPO activity gradually increased in Ramsey rootstock cuttings from 10 days to 22 days, in Lot and 99R cuttings at 14 days, and then decreased until 51 days. A significant correlation was identified between high POX activity and adventitious rooting capability in rootstocks, but the same result was not determined with PPO activity. A recalcitrant rooting variety cannot increase POX activity sufficiently before rooting. Therefore applications that could increase POX activity in stem cuttings during rooting may facilitate increased rooting in such rootstocks. Copyright © 2011 Society of Chemical Industry.

  17. Enzyme hydration, activity and flexibility : A neutron scattering approach

    International Nuclear Information System (INIS)

    Kurkal-Siebert, V.; Finney, J.L.; Daniel, R.M.; Smith, Jeremy C.

    2006-01-01

    Recent measurements have demonstrated enzyme activity at hydrations as low as 3%. The question of whether the hydration-induced enzyme flexibility is important for activity is addressed by performing picosecond dynamic neutron scattering experiments on pig liver esterase powders at various temperatures as well as solutions. At all temperatures and hydrations investigated here, significant quasielastic scattering intensity is found in the protein, indicating the presence of anharmonic, diffusive motion. As the hydration increases a temperature-dependent dynamical transition appears and strengthens involving additional diffusive motion. At low temperature, increasing hydration resulted in lower flexibility of the enzyme. At higher temperatures, systems containing sufficient number of water molecules interacting with the protein exhibit increased flexibility. The implication of these results is that, although the additional hydration-induced diffusive motion and flexibility at high temperatures in the enzyme detected here may be related to increased activity, they are not required for the enzyme to function

  18. Activity enhancement of ligninolytic enzymes of Trametes versicolor ...

    African Journals Online (AJOL)

    Suspended cultures of white-rot fungus, Trametes versicolor, supplemented with bagasse powder showed a concentration dependent enhancement in the ligninolytic enzymes activity in liquid shake cultures. 2% (w/v) bagasse powder improved greater stability to the enzymes. The optimum pH is 3.5 and the optimum ...

  19. Changes in growth, survival and digestive enzyme activities of Asian ...

    African Journals Online (AJOL)

    A study was conducted to determine the effects of different dietary treatments on the growth, survival and digestive enzyme activities of Mystus nemurus larvae. Newly hatched larvae were reared for 14 days in twelve 15 L glass aquaria (for growth and survival) and eight 300 L fiberglass tanks (for enzyme samples) at a ...

  20. Ligninolytic enzyme activities in mycelium of some wild and ...

    African Journals Online (AJOL)

    Lignin is probably one of the most recalcitrant compounds synthesized by plants. This compound is degraded by few microorganisms. White-rot fungi have been extensively studied due to its powerful ligninolytic enzymes. In this study, ligninolytic enzyme activities of different fungal species (six commercial and 13 wild) were ...

  1. Effect of diffusion on enzyme activity in a microreactor

    NARCIS (Netherlands)

    Swarts, J.W.; Kolfschoten, R.C.; Jansen, M.C.A.A.; Janssen, A.E.M.; Boom, R.M.

    2010-01-01

    To establish general rules for setting up an enzyme microreactor system, we studied the effect of diffusion on enzyme activity in a microreactor. As a model system we used the hydrolysis of ortho-nitrophenyl-ß-d-galactopyranoside by ß-galactosidase from Kluyveromyces lactis. We found that the

  2. Dibromine radical anion reactions with heme enzymes

    International Nuclear Information System (INIS)

    Gebicka, L.; Gebicki, J.L.

    1996-01-01

    Reactions of Br 2 radical anion with heme enzymes, catalase horseradish peroxidase, have been studied by pulse radiolysis. It has been found that Br 2 - does not react with the heme centre of investigated enzymes. Dibromine radical anion reacts with tryptophan residues of catalase without any influence on the activity of catalase. It is suggested that in pulse radiolysis studies, where horseradish peroxidase is at about tenfold excess toward Br 2 - , the enzyme is modified rather by Br 2 , than by Br 2 - . (author). 26 refs., 3 figs

  3. General discussion about enzymes activities of radiation injury

    International Nuclear Information System (INIS)

    Vucicevic, M.; Sukalo, I.

    1989-01-01

    Researching reliable and practical indicators of radiation injury, however, is very interesting and considerable department of scientific studies, practical and theoretical. Enzymes activities are among biochemical indicators which are changed after radiation injury. Activity of these specific proteins is important in regulation of every biochemical reaction in existing beings. Biological macromolecules can be damaged by radiation or the cell permeability can be changed. All of these influence directly on enzymes activities. In this paper we present the review of the all important enzymes, indicators of the radiation injury, which variances on reference to normal values are significant of the functional and the structural changes of essential organs (author)

  4. General discussion about enzymes activities of radiation injury

    Energy Technology Data Exchange (ETDEWEB)

    Vucicevic, M; Sukalo, I [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1989-07-01

    Researching reliable and practical indicators of radiation injury, however, is very interesting and considerable department of scientific studies, practical and theoretical. Enzymes activities are among biochemical indicators which are changed after radiation injury. Activity of these specific proteins is important in regulation of every biochemical reaction in existing beings. Biological macromolecules can be damaged by radiation or the cell permeability can be changed. All of these influence directly on enzymes activities. In this paper we present the review of the all important enzymes, indicators of the radiation injury, which variances on reference to normal values are significant of the functional and the structural changes of essential organs (author)

  5. The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase.

    Science.gov (United States)

    Harrison-Findik, Duygu Dee; Lu, Sizhao

    2015-05-06

    This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1(-/-) mice. Alcohol increased H2O2 production in catalase(-/-) and wild-type, but not gpx-1(-/-), mice. Hepcidin expression was inhibited in alcohol-fed catalase(-/-) and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1(-/-) mice. Gpx-1(-/-) mice also displayed higher level of basal liver CHOP protein expression than catalase(-/-) mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1(-/-) mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1(-/-) mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

  6. Msn2p/Msn4p act as a key transcriptional activator of yeast cytoplasmic thiol peroxidase II.

    Science.gov (United States)

    Hong, Seung-Keun; Cha, Mee-Kyung; Choi, Yong-Soo; Kim, Won-Cheol; Kim, Il-Han

    2002-04-05

    We observed that the transcription of Saccharomyces cerevisiae cytoplasmic thiol peroxidase type II (cTPx II) (YDR453C) is regulated in response to various stresses (e.g. oxidative stress, carbon starvation, and heat-shock). It has been suggested that both transcription-activating proteins, Yap1p and Skn7p, regulate the transcription of cTPx II upon exposure to oxidative stress. However, a dramatic loss of transcriptional response to various stresses in yeast mutant strains lacking both Msn2p and Msn4p suggests that the transcription factors act as a principal transcriptional activator. In addition to two Yap1p response elements (YREs), TTACTAA and TTAGTAA, the presence of two stress response elements (STREs) (CCCCT) in the upstream sequence of cTPx II also suggests that Msn2p/Msn4p could control stress-induced expression of cTPx II. Analysis of the transcriptional activity of site-directed mutagenesis of the putative STREs (STRE1 and STRE2) and YREs (TRE1 and YRE2) in terms of the activity of a lacZ reporter gene under control of the cTPx II promoter indicates that STRE2 acts as a principal binding element essential for transactivation of the cTPx II promoter. The transcriptional activity of the cTPx II promoter was exponentially increased after postdiauxic growth. The transcriptional activity of the cTPx II promoter is greatly increased by rapamycin. Deletion of Tor1, Tor2, Ras1, and Ras2 resulted in a considerable induction when compared with their parent strains, suggesting that the transcription of cTPx II is under negative control of the Ras/cAMP and target of rapamycin signaling pathways. Taken together, these results suggest that cTPx II is a target of Msn2p/Msn4p transcription factors under negative control of the Ras-protein kinase A and target of rapamycin signaling pathways. Furthermore, the accumulation of cTPx II upon exposure to oxidative stress and during the postdiauxic shift suggests an important antioxidant role in stationary phase yeast cells.

  7. Antioxidant enzymes activity in embryogenic and non-embryogenic tissues in Sugarcane

    International Nuclear Information System (INIS)

    Marina Medeiros de Araujo Silva; Ulisses, Claudia; Lacerda E Medeiros, Maria Jaislanny; Cavalcante Granja, Manuela Maria; Willadino, Lilia; Camara, Terezinha

    2014-01-01

    The objective of this work was to induce direct somatic embryogenesis from segments of immature leaves of the RB872552 variety of sugarcane and to correlate this morphogenic event with oxidative stress. Two previously described protocols were utilized for the induction of somatic embryogenesis in sugarcane with different supplementations of the culture medium and different incubation conditions. For the conversion of embryos into plants was used ms medium without phytoregulators. Histological analyses and activity of antioxidant enzymes were also conducted for the embryogenic and non-embryogenic tissues. The formation of somatic embryos was obtained in 81 % of the explants with the combination of regulators 2,4-D (2,4-dichlorophenoxyacetic acid)and BAP (6-benzylaminopurine) when incubated under 16 h photoperiod. With regards to the antioxidant enzymes, there was increased activity of peroxidase and an increase in the soluble protein content in embryogenic tissues, whereas lower activities of polyphenol oxidase and catalase appeared in these tissues compared to nonembryogenic tissues. It could be inferred that oxidative stress plays an important role in the induction of somatic embryogenesis in sugarcane.

  8. Lignin peroxidase isoenzyme: a novel approach to biodegrade the toxic synthetic polymer waste.

    Science.gov (United States)

    Khatoon, Nazia; Jamal, Asif; Ali, Muhammad Ishtiaq

    2018-01-05

    Fungal metabolites are playing an immense role in developing various sustainable waste treatment processes. The present study aimed at production and characterization of fungal lignin peroxidase (EC 1.11.1.14) with a potential to degrade Polyvinyl Chloride. Optimization studies revealed that the maximum enzyme production occurred at a temperature 25°C, pH 5 in the 4th week of the incubation period with fungal strain. Enzyme assay was performed to find out the dominating enzyme in the culture broth. The molecular weight of the enzyme was found to be 46 kDa. Partially purified lignin peroxidase from Phanerocheate chrysosporium was used for the degradation of PVC films. A significant reduction in the weight of PVC film was observed (31%) in shake flask experiment. FTIR spectra of the enzyme-treated plastic film revealed structural changes in the chemical composition, indicating a specific peak at 2943 cm -1 that corresponded to alkenyl C-H stretch. Moreover, deterioration on the surface of PVC films was confirmed by Scanning Electron Microscopy tracked through activity assay for the lignin peroxidase. Extracellular lignin peroxidases from P. chrysosporium play a significant role in the degradation of complex polymeric compounds like PVC.

  9. Radioimmunoassays for catalase and glutathion peroxidase

    International Nuclear Information System (INIS)

    Baret, A.; Courtiere, A.; Lorry, D.; Puget, K.; Michelson, A.M.

    1982-01-01

    Specific and sensitive radioimmunoassays for human, bovine and rat catalase (CAT) and glutathion Peroxidase (GPX) are described. The obtained values are expressed as enzymatic units per μg of immunoreactive protein. They appear to closely correspond to specific activities of the purified enzymes determined by colorimetric protein-assay. Indeed, the values of the specific activities of purified human CAT is 57.9 k/mg and that of purified rat GPX is 180 units/mg. This result validates the present RIAs and the association of the two techniques allows the determination of a further parameter. In conclusion, RIAs for CAT and GPX can be applied with great specificity and sensitivity to a wide variety of human, rat and bovine medias

  10. Nitroxides protect horseradish peroxidase from H2O2-induced inactivation and modulate its catalase-like activity.

    Science.gov (United States)

    Samuni, Amram; Maimon, Eric; Goldstein, Sara

    2017-08-01

    Horseradish peroxidase (HRP) catalyzes H 2 O 2 dismutation while undergoing heme inactivation. The mechanism underlying this process has not been fully elucidated. The effects of nitroxides, which protect metmyoglobin and methemoglobin against H 2 O 2 -induced inactivation, have been investigated. HRP reaction with H 2 O 2 was studied by following H 2 O 2 depletion, O 2 evolution and heme spectral changes. Nitroxide concentration was followed by EPR spectroscopy, and its reactions with the oxidized heme species were studied using stopped-flow. Nitroxide protects HRP against H 2 O 2 -induced inactivation. The rate of H 2 O 2 dismutation in the presence of nitroxide obeys zero-order kinetics and increases as [nitroxide] increases. Nitroxide acts catalytically since its oxidized form is readily reduced to the nitroxide mainly by H 2 O 2 . The nitroxide efficacy follows the order 2,2,6,6-tetramethyl-piperidine-N-oxyl (TPO)>4-OH-TPO>3-carbamoyl proxyl>4-oxo-TPO, which correlates with the order of the rate constants of nitroxide reactions with compounds I, II, and III. Nitroxide catalytically protects HRP against inactivation induced by H 2 O 2 while modulating its catalase-like activity. The protective role of nitroxide at μM concentrations is attributed to its efficient oxidation by P940, which is the precursor of the inactivated form P670. Modeling the dismutation kinetics in the presence of nitroxide adequately fits the experimental data. In the absence of nitroxide the simulation fits the observed kinetics only if it does not include the formation of a Michaelis-Menten complex. Nitroxides catalytically protect heme proteins against inactivation induced by H 2 O 2 revealing an additional role played by nitroxide antioxidants in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Stability and Catalytic Kinetics of Horseradish Peroxidase Confined in Nanoporous SBA-15

    DEFF Research Database (Denmark)

    Ikemoto, Hediki; Chi, Qijin; Ulstrup, Jens

    2010-01-01

    We have synthesized nanoporous silica, SBA-15 in the 1 m size range with the pore diameter of 7.6 nm. The redox enzyme horseradish peroxidase (HRP) was entrapped in the pores to form nanostructured hybrid materials. The catalytic activity of free and immobilized enzyme was first compared at room...... likely due to different hydrogen bonding of water and increased hydration strength of the protein inside the nanopores....

  12. Regenerative Capacity of Cacti Schlumbergera and Rhipsalidopsis in Relation to Endogenous Phytohormones, Cytokinin Oxidase/Dehydrogenase, and Peroxidase Activities

    Czech Academy of Sciences Publication Activity Database

    Sriskandarajah, S.; Prinsen, E.; Motyka, Václav; Dobrev, Petre; Serek, M.

    2006-01-01

    Roč. 25, č. 1 (2006), s. 79-88 ISSN 0721-7595 R&D Projects: GA ČR GA206/03/0313 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cytokinin dehydrogenase * Cytokinin oxidase * Endogenous phytohormones * In vitro regeneration * Peroxidase * Rhipsalidopsis * Schlumbergera Subject RIV: EF - Botanics Impact factor: 2.107, year: 2006

  13. A redox-dependent dimerization switch regulates activity and tolerance for reactive oxygen species of barley seed glutathione peroxidase

    DEFF Research Database (Denmark)

    Navrot, Nicolas; Skjoldager, Nicklas; Bunkenborg, Jakob

    2015-01-01

    Monomeric and dimeric forms of recombinant barley (Hordeum vulgare subsp. vulgare) glutathione peroxidase 2 (HvGpx2) are demonstrated to display distinctly different functional properties in vitro. Monomeric HvGpx2 thus has five fold higher catalytic efficiency than the dimer towards tert-butyl h...

  14. Compounds from silicones alter enzyme activity in curing barnacle glue and model enzymes.

    Science.gov (United States)

    Rittschof, Daniel; Orihuela, Beatriz; Harder, Tilmann; Stafslien, Shane; Chisholm, Bret; Dickinson, Gary H

    2011-02-17

    Attachment strength of fouling organisms on silicone coatings is low. We hypothesized that low attachment strength on silicones is, in part, due to the interaction of surface available components with natural glues. Components could alter curing of glues through bulk changes or specifically through altered enzyme activity. GC-MS analysis of silicone coatings showed surface-available siloxanes when the coatings were gently rubbed with a cotton swab for 15 seconds or given a 30 second rinse with methanol. Mixtures of compounds were found on 2 commercial and 8 model silicone coatings. The hypothesis that silicone components alter glue curing enzymes was tested with curing barnacle glue and with commercial enzymes. In our model, barnacle glue curing involves trypsin-like serine protease(s), which activate enzymes and structural proteins, and a transglutaminase which cross-links glue proteins. Transglutaminase activity was significantly altered upon exposure of curing glue from individual barnacles to silicone eluates. Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents. Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties. Altered curing of natural glues has potential in fouling management.

  15. Change in catalase and peroxidase activity in rat blood in case of combined radiation and mechanical injuries

    International Nuclear Information System (INIS)

    Volkovaya, T.A.

    1982-01-01

    Changes of catalase and peroxide activity of blood in rats in case of irradiation at 2.0 and 7.0 Gy, mechanical injury of animal chest and combined radiation injury were studied. The given data testify to considerable increase of the above enzymes activity in case of all these effects. The less decrease of catalase and peroxide activity was observed after infliction of mechanical injury alone. Aggravating effect of mechanical injury on the irradiated organism leads to more noticeable decrease of catalase activity (at early periods of observation) in comparison with radiation effect. Peroxide changes in case of combined radiation and mechanical injury of rats differ slightly from similar factors observed in case of irradiation alone

  16. Changes in photosynthesis and activities of enzymes involved in ...

    African Journals Online (AJOL)

    tolerance, respectively were used to investigate the oxygen consumption rate of photosystem I, the oxygen evolution rate of photosystem II, cab transcript levels, and activities of enzymes involved in photosynthetic carbon reduction cycle.

  17. activity of enzyme trypsin immobilized onto macroporous poly(epoxy

    African Journals Online (AJOL)

    dell

    consequential effects of covalent immobilization. EXPERIMENTAL. Materials .... immersed into water bath. ... storage stability of the enzyme was studied ... pore size range of about 10 to 150 µm. ... figures, the differences in activities (slopes.

  18. Seasonality of fibrolytic enzyme activity in herbivore microbial ...

    African Journals Online (AJOL)

    2012-08-21

    Aug 21, 2012 ... liberating end-products such as volatile fatty acids. Cellulase enzyme ... All the other common chemicals such as glacial acetic acid, sodium azide .... specific activity was observed among animal species and between seasons ...

  19. Changes in activities of tissues enzymes in rats administered Ficus ...

    African Journals Online (AJOL)

    This study evaluates the effects of methanolic extract of Ficus exasperata leaf on the ... measuring the levels of some key enzymes in ... powder using an electrical blender. .... of the cells at these doses. .... activities and acute toxicity of a stem.

  20. Identification and characterization of a selenium-dependent glutathione peroxidase in Setaria cervi

    International Nuclear Information System (INIS)

    Singh, Anchal; Rathaur, Sushma

    2005-01-01

    Setaria cervi a bovine filarial parasite secretes selenium glutathione peroxidase during in vitro cultivation. A significant amount of enzyme activity was detected in the somatic extract of different developmental stages of the parasite. Among different stages, microfilariae showed a higher level of selenium glutathione peroxidase activity followed by males then females. However, when the activity was compared in excretory secretory products of these stages males showed higher activity than microfilariae and female worms. The enzyme was purified from female somatic extract using a combination of glutathione agarose and gel filtration chromatography, which migrated as a single band of molecular mass ∼20 kDa. Selenium content of purified enzyme was estimated by atomic absorption spectroscopy and found to be 3.5 ng selenium/μg of protein. Further, inhibition of enzyme activity by potassium cyanide suggested the presence of selenium at the active site of enzyme. This is the first report of identification of selenium glutathione peroxidase from any filarial parasite

  1. Purification and characterization of peroxidase from avocado (Persea americana Mill, cv. Hass).

    Science.gov (United States)

    Rojas-Reyes, José O; Robles-Olvera, Victor; Carvajal-Zarrabal, Octavio; Castro Matinez, Claudia; Waliszewski, Krzysztof N; Aguilar-Uscanga, María Guadalupe

    2014-07-01

    Avocado (Persea americana Mill, cv. Hass) fruit ranks tenth in terms of the most important products for Mexico. Avocado products are quite unstable due to the presence of oxidative enzymes such as polyphenol oxidase and peroxidase. The present study is to characterize the activity of purified avocado peroxidase from avocado in order to ascertain the biochemical and kinetic properties and their inhibition conditions. Purification was performed by Sephacryl S 200 HR gel filtration chromatography and its estimated molecular weight was 40 kDa. The zymogram showed an isoelectric point of 4.7. Six substrates were tested in order to ascertain the affinity of the enzyme for these substrates. The purified peroxidase was found to have low Km (0.296 mM) and high catalytic efficiency (2688 mM(-1) s(-1)) using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), optimum activity being reached at 51°C, pH 3.8. The addition of dithiothreitol, β-mercaptoethanol, ascorbic acid, sodium azide, L-cysteine and Tween-20 had high inhibitory effects, while metals ions such as Cu(+), Fe(2+) and Mn(2+) had weak inhibitory activity on purified avocado peroxidase. The purified avocado peroxidase exhibits high inhibition (Ki = 0.37 µM) with 1.97 µM n-propyl gallate using ABTS as substrate at 51°C, pH 3.8 for 10 min. © 2013 Society of Chemical Industry.

  2. Apparent expression of flower colours and internal variation of enzyme activities in some typical phenotypes of dyer's saffron cultivars

    Directory of Open Access Journals (Sweden)

    Koshi Saito

    2014-01-01

    Full Text Available Phytochemical screening of four Carthamus pigments in phenotypically different cultivars of dyer's saffron was carried out by means of chromatographic techniques. The pigment composition in the floral part correlated well with the flower colour, supporting these components as idoneous chemotaxonomic markers. Among seven cultivars examined, three were orange-yellow and contained carthamin (red and precarthamin, safflor yellow A and safflor yellow B (orange-yellow (type 0. There were bright-yellow and also had the above four pigments (type Y. The seventh cultivar was ivory-white and produced no quinoidal chalcones in the florets (type W. Relative activities of three different enzymes were examined in soluble protein extracts from etiolated seedlings of the garden varieties. Monophenol monooxygenase (EC 1.14.18.1 and peroxidase (EC 1.11.1.7. were distributed over all cultivars tested. The relative level of the enzyme activities could be ordered as follows: type 0, type W and type Y. The activity of a carthamin-synthesizing enzyme was found in the protein extracts from all garden forms examined. Its activity was most prominent in type O. The activity level in type W was inferior to that of type O. The catalytic intensity in type Y was found to even lower. The results were discussed as to the composition of the phenotypic markers and the distribution of the enzyme activities in three different garden forms of dyer's saffron cultivars.

  3. Enzyme activity measurement via spectral evolution profiling and PARAFAC

    DEFF Research Database (Denmark)

    Baum, Andreas; Meyer, Anne S.; Garcia, Javier Lopez

    2013-01-01

    The recent advances in multi-way analysis provide new solutions to traditional enzyme activity assessment. In the present study enzyme activity has been determined by monitoring spectral changes of substrates and products in real time. The method relies on measurement of distinct spectral...... fingerprints of the reaction mixture at specific time points during the course of the whole enzyme catalyzed reaction and employs multi-way analysis to detect the spectral changes. The methodology is demonstrated by spectral evolution profiling of Fourier Transform Infrared (FTIR) spectral fingerprints using...

  4. Analysis of metallotionein expression and antioxidant enzyme activities in Meretrix meretrix larvae under sublethal cadmium exposure

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qing [Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7th Nanhai Road, Qingdao 266071 (China); Graduate University, Chinese Academy of Sciences, Beijing 100049 (China); Wang Xiaomei [Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Wang Xiaoyu [Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7th Nanhai Road, Qingdao 266071 (China); Engineering Research Center of Seawater Utilization Technology, Ministry of Education, Hebei University of Technology, Tianjin 300130 (China); Yang Hongsheng, E-mail: hshyang@ms.qdio.ac.cn [Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, 7th Nanhai Road, Qingdao 266071 (China); Liu Baozhong, E-mail: bzliu@ms.qdio.ac.cn [Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China)

    2010-11-15

    To investigate the possible role of metallothioneins (MTs) and antioxidant enzymes in cadmium (Cd) tolerance in Meretrix meretrix larvae, a new MT (designated MmMT) gene was identified and cloned from M. meretrix. The full-length cDNA of MmMT consisted of an open reading frame (ORF) of 231 bp encoding a protein of 76 amino acids, with 21 cysteine residues and a conserved structural pattern Cys-x-Cys-x(3)-Cys-Tyr-Gly-x(3)-Cys-x-Cys-x(3)-Cys-x-Cys-Lys at the C-terminus. The deduced amino acid sequence of MmMT showed about 57-84% identity with previously published MT sequences of mussels and oysters. Real-time PCR was used to analyze the expression level of MmMT mRNA at different M. meretrix larval stages under Cd exposure (25 {mu}g L{sup -1}). Results showed that Cd could induce the expression of MmMT mRNA in the larvae, and the expression level increased 5.04-fold and 3.99-fold in D-shaped larvae and pediveligers, respectively. Immunolocalization of MmMT in the stressed larvae revealed that MmMT was synthesized in almost all of the soft parts at the trochophore and postlarva stages, whereas it was only synthesized in the velum and epidermis at the D-shaped larva and pediveliger stages. The activities of three antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), also were measured in larvae at different developmental stages. Increased enzymatic activities were detected mainly in D-shaped larvae and pediveligers under Cd stress, suggesting that these enzymes respond synchronously with MT. Our results indicate that MmMT and antioxidant enzymes played important roles in counteracting Cd stress in M. meretrix larvae.

  5. Analysis of metallotionein expression and antioxidant enzyme activities in Meretrix meretrix larvae under sublethal cadmium exposure

    International Nuclear Information System (INIS)

    Wang Qing; Wang Xiaomei; Wang Xiaoyu; Yang Hongsheng; Liu Baozhong

    2010-01-01

    To investigate the possible role of metallothioneins (MTs) and antioxidant enzymes in cadmium (Cd) tolerance in Meretrix meretrix larvae, a new MT (designated MmMT) gene was identified and cloned from M. meretrix. The full-length cDNA of MmMT consisted of an open reading frame (ORF) of 231 bp encoding a protein of 76 amino acids, with 21 cysteine residues and a conserved structural pattern Cys-x-Cys-x(3)-Cys-Tyr-Gly-x(3)-Cys-x-Cys-x(3)-Cys-x-Cys-Lys at the C-terminus. The deduced amino acid sequence of MmMT showed about 57-84% identity with previously published MT sequences of mussels and oysters. Real-time PCR was used to analyze the expression level of MmMT mRNA at different M. meretrix larval stages under Cd exposure (25 μg L -1 ). Results showed that Cd could induce the expression of MmMT mRNA in the larvae, and the expression level increased 5.04-fold and 3.99-fold in D-shaped larvae and pediveligers, respectively. Immunolocalization of MmMT in the stressed larvae revealed that MmMT was synthesized in almost all of the soft parts at the trochophore and postlarva stages, whereas it was only synthesized in the velum and epidermis at the D-shaped larva and pediveliger stages. The activities of three antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), also were measured in larvae at different developmental stages. Increased enzymatic activities were detected mainly in D-shaped larvae and pediveligers under Cd stress, suggesting that these enzymes respond synchronously with MT. Our results indicate that MmMT and antioxidant enzymes played important roles in counteracting Cd stress in M. meretrix larvae.

  6. Defoliation effects on enzyme activities of the ectomycorrhizal fungus Suillus granulatus in a Pinus contorta (lodgepole pine) stand in Yellowstone National Park.

    Science.gov (United States)

    Cullings, Ken; Ishkhanova, Galina; Henson, Joan

    2008-11-01

    Ectomycorrhizal (EM) basidiomycete fungi are obligate mutualists of pines and hardwoods that receive fixed C from the host tree. Though they often share most recent common ancestors with wood-rotting fungi, it is unclear to what extent EM fungi retain the ability to express enzymes that break down woody substrates. In this study, we tested the hypothesis that the dominant EM fungus in a pure pine system retains the ability to produce enzymes that break down woody substrates in a natural setting, and that this ability is inducible by reduction of host photosynthetic potential via partial defoliation. To achieve this, pines in replicate blocks were defoliated 50% by needle removal, and enzyme activities were measured in individual EM root tips that had been treated with antibiotics to prevent possible bacterial activity. Results indicate that the dominant EM fungal species (Suillus granulatus) expressed all enzymes tested (endocellulase D: -glucosidase, laccase, manganese peroxidase, lignin peroxidase, phosphatase and protease), and that activities of these enzymes increased significantly (P pine) has the potential to play a significant role in C, N and P cycling in this forested ecosystem. Therefore, many above-ground factors that reduce photosynthetic potential or divert fixed C from roots may have wide-reaching ecosystem effects.

  7. Comparative effect of Piper betle, Chlorella vulgaris and tocotrienol-rich fraction on antioxidant enzymes activity in cellular ageing of human diploid fibroblasts.

    Science.gov (United States)

    Makpol, Suzana; Yeoh, Thong Wei; Ruslam, Farah Adilah Che; Arifin, Khaizurin Tajul; Yusof, Yasmin Anum Mohd

    2013-08-16

    Human diploid fibroblasts (HDFs) undergo a limited number of cellular divisions in culture and progressively reach a state of irreversible growth arrest, a process termed cellular ageing. Even though beneficial effects of Piper betle, Chlorella vulgaris and tocotrienol-rich fraction (TRF) have been reported, ongoing studies in relation to ageing is of interest to determine possible protective effects that may reverse the effect of ageing. The aim of this study was to evaluate the effect of P. betle, C. vulgaris and TRF in preventing cellular ageing of HDFs by determining the activity of antioxidant enzymes viz.; catalase, superoxide dismutase (SOD) and glutathione peroxidase. Different passages of HDFs were treated with P. betle, C. vulgaris and TRF for 24 h prior to enzymes activity determination. Senescence-associated beta-galactosidase (SA β-gal) expression was assayed to validate cellular ageing. In cellular ageing of HDFs, catalase and glutathione peroxidase activities were reduced, but SOD activity was heightened during pre-senescence. P. betle exhibited the strongest antioxidant activity by reducing SA β-gal expression, catalase activities in all age groups, and SOD activity. TRF exhibited a strong antioxidant activity by reducing SA β-gal expression, and SOD activity in senescent HDFs. C. vulgaris extract managed to reduce SOD activity in senescent HDFs. P. betle, C. vulgaris, and TRF have the potential as anti-ageing entities which compensated the role of antioxidant enzymes in cellular ageing of HDFs.

  8. Comparative effect of Piper betle, Chlorella vulgaris and tocotrienol-rich fraction on antioxidant enzymes activity in cellular ageing of human diploid fibroblasts

    Science.gov (United States)

    2013-01-01

    Background Human diploid fibroblasts (HDFs) undergo a limited number of cellular divisions in culture and progressively reach a state of irreversible growth arrest, a process termed cellular ageing. Even though beneficial effects of Piper betle, Chlorella vulgaris and tocotrienol-rich fraction (TRF) have been reported, ongoing studies in relation to ageing is of interest to determine possible protective effects that may reverse the effect of ageing. The aim of this study was to evaluate the effect of P. betle, C. vulgaris and TRF in preventing cellular ageing of HDFs by determining the activity of antioxidant enzymes viz.; catalase, superoxide dismutase (SOD) and glutathione peroxidase. Methods Different passages of HDFs were treated with P. betle, C. vulgaris and TRF for 24 h prior to enzymes activity determination. Senescence-associated beta-galactosidase (SA β-gal) expression was assayed to validate cellular ageing. Results In cellular ageing of HDFs, catalase and glutathione peroxidase activities were reduced, but SOD activity was heightened during pre-senescence. P. betle exhibited the strongest antioxidant activity by reducing SA β-gal expression, catalase activities in all age groups, and SOD activity. TRF exhibited a strong antioxidant activity by reducing SA β-gal expression, and SOD activity in senescent HDFs. C. vulgaris extract managed to reduce SOD activity in senescent HDFs. Conclusion P. betle, C. vulgaris, and TRF have the potential as anti-ageing entities which compensated the role of antioxidant enzymes in cellular ageing of HDFs. PMID:23948056

  9. Changes in antioxidant enzyme activities in Eichhornia crassipes (Pontederiaceae) and Pistia stratiotes (Araceae) under heavy metal stress

    International Nuclear Information System (INIS)

    Odjegba, V. J.; Fasidi, I. O.

    2007-01-01

    Whole plants of Eichhornia crassipes and Pistia stratiotes were exposed to various concentrations (0,0.1, 0.3, 0.5, 1.0, 3.0 and 5.0 mM) of 8 heavy metals (Ag, Cd, Cr, Cu, Hg, Ni, Pb and Zn) hydroponically for 21 days. Spectrometric assays for the total activity of catalase, peroxidase, and superoxide dismutase in the leaves were studied. At the end of the experimental period, data referred to metal treated plants were compared to data of untreated ones (control). Heavy metals increased the activity of catalase, peroxidase and superoxide dismutase in both species and there was differential inducement among metals. Overall, Zn had the least inducement of antioxidant enzymes in both species while Hg had the highest inducement. The increase in antioxidant enzymes in relation to the control plants was more in E. crassipes than P. stratiotes. The results showed that E. crassipes tolerated higher metal concentrations in a greater number of metals than P. stratiotes. (author)

  10. Biotransformation of albendazole and activities of selected detoxification enzymes in Haemonchus contortus strains susceptible and resistant to anthelmintics.

    Science.gov (United States)

    Vokřál, Ivan; Jirásko, Robert; Stuchlíková, Lucie; Bártíková, Hana; Szotáková, Barbora; Lamka, Jiří; Várady, Marián; Skálová, Lenka

    2013-09-23

    The increased activity of drug-metabolizing enzymes can protect helminths against the toxic effect of anthelmintics. The aim of this study was to compare the metabolism of the anthelmintic drug albendazole (ABZ) and the activities of selected biotransformation and antioxidant enzymes in three different strains of Haemonchus contortus: the ISE strain (susceptible to common anthelmintics), the BR strain (resistant to benzimidazole anthelmintics) and the WR strain (multi-resistant). H. contortus adults were collected from the abomasum of experimentally infected lambs. In vitro (subcellular fractions of H. contortus homogenate) as well as ex vivo (living nematodes cultivated in flasks with medium) experiments were performed. HPLC with spectrofluorimetric and mass-spectrometric detection was used in the analysis of ABZ metabolites. The in vitro activities of oxidation/antioxidation and conjugation enzymes toward model substrates were also assayed. The in vitro data showed significant differences between the susceptible (ISE) and resistant (BR, WR) strains regarding the activities of peroxidases, catalase and UDP-glucosyltransferases. S-oxidation of ABZ was significantly lower in BR than in the ISE strain. Ex vivo, four ABZ metabolites were identified: ABZ sulphoxide and three ABZ glucosides. In the resistant strains BR and WR, the ex vivo formation of all ABZ glucosides was significantly higher than in the susceptible ISE strain. The altered activities of certain detoxifying enzymes might partly protect the parasites against the toxic effect of the drugs as well as contribute to drug-resistance in these parasites. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Antioxidant Enzyme Activity and Meat Quality of Meat Type Ducks Fed with Dried Oregano ( L. Powder

    Directory of Open Access Journals (Sweden)

    J. H. Park

    2015-01-01

    Full Text Available One-day-old Cherry valley meat-strain ducks were used to investigate the effect of supplemental dried oregano powder (DOP in feed on the productivity, antioxidant enzyme activity, and breast meat quality. One hundred sixty five ducks were assigned to 5 dietary treatments for 42 days. The dietary treatment groups were control group (CON; no antibiotic, no DOP, antibiotic group (ANT; CON+0.1% Patrol, 0.1% DOP (CON+0.1% DOP, 0.5% DOP (CON+0.5% DOP, and 1.0% DOP (CON+1.0% DOP. Upon feeding, 1,1-diphenyl-2-picryl-hydrazyl (DPPH radical scavenging activity of oregano extracts was higher than that of tocopherol, although it was less than that of ascorbic acid. As a result of in vivo study, DOP in the diet showed no effects on final body weight, feed intake, or feed conversion ratio. However, dietary 0.5% and 1% DOP supplementation caused a significant increase in the serum enzyme activity of superoxide dismutase (SOD compared with CON and ANT, while glutathione peroxidase (GPx in tissue was increased as compared to ANT (p<0.05. Cooking loss from ducks fed with DOP decreased compared with the control ducks. Thiobarbituric acid reactive substance (TBARS values of duck breast meat at 5 d post slaughter was found to be significantly reduced in ducks whose diets were supplemented with 0.5% and 1% DOP (p<0.05. These results suggest that diets containing 0.5% and 1% DOP may beneficially affect antioxidant enzyme activity of GPx and SOD, improve meat cooking loss, and reduce TBARS values in breast meat at 5 d of storage in ducks.

  12. Hfq stimulates the activity of the CCA-adding enzyme

    Directory of Open Access Journals (Sweden)

    Betat Heike

    2007-10-01

    Full Text Available Abstract Background The bacterial Sm-like protein Hfq is known as an important regulator involved in many reactions of RNA metabolism. A prominent function of Hfq is the stimulation of RNA polyadenylation catalyzed by E. coli poly(A polymerase I (PAP. As a member of the nucleotidyltransferase superfamily, this enzyme shares a high sequence similarity with an other representative of this family, the tRNA nucleotidyltransferase that synthesizes the 3'-terminal sequence C-C-A to all tRNAs (CCA-adding enzyme. Therefore, it was assumed that Hfq might not only influence the poly(A polymerase in its specific activity, but also other, similar enzymes like the CCA-adding enzyme. Results Based on the close evolutionary relation of these two nucleotidyltransferases, it was tested whether Hfq is a specific modulator acting exclusively on PAP or whether it also influences the activity of the CCA-adding enzyme. The obtained data indicate that the reaction catalyzed by this enzyme is substantially accelerated in the presence of Hfq. Furthermore, Hfq binds specifically to tRNA transcripts, which seems to be the prerequisite for the observed effect on CCA-addition. Conclusion The increase of the CCA-addition in the presence of Hfq suggests that this protein acts as a stimulating factor not only for PAP, but also for the CCA-adding enzyme. In both cases, Hfq interacts with RNA substrates, while a direct binding to the corresponding enzymes was not demonstrated up to now (although experimental data indicate a possible interaction of PAP and Hfq. So far, the basic principle of these stimulatory effects is not clear yet. In case of the CCA-adding enzyme, however, the presented data indicate that the complex between Hfq and tRNA substrate might enhance the product release from the enzyme.

  13. Dynamic relationships between microbial biomass, respiration, inorganic nutrients and enzyme activities: informing enzyme based decomposition models

    Directory of Open Access Journals (Sweden)

    Daryl L Moorhead

    2013-08-01

    Full Text Available We re-examined data from a recent litter decay study to determine if additional insights could be gained to inform decomposition modeling. Rinkes et al. (2013 conducted 14-day laboratory incubations of sugar maple (Acer saccharum or white oak (Quercus alba leaves, mixed with sand (0.4% organic C content or loam (4.1% organic C. They measured microbial biomass C, carbon dioxide efflux, soil ammonium, nitrate, and phosphate concentrations, and β-glucosidase (BG, β-N-acetyl-glucosaminidase (NAG, and acid phosphatase (AP activities on days 1, 3, and 14. Analyses of relationships among variables yielded different insights than original analyses of individual variables. For example, although respiration rates per g soil were higher for loam than sand, rates per g soil C were actually higher for sand than loam, and rates per g microbial C showed little difference between treatments. Microbial biomass C peaked on day 3 when biomass-specific activities of enzymes were lowest, suggesting uptake of litter C without extracellular hydrolysis. This result refuted a common model assumption that all enzyme production is constitutive and thus proportional to biomass, and/or indicated that part of litter decay is independent of enzyme activity. The length and angle of vectors defined by ratios of enzyme activities (BG/NAG versus BG/AP represent relative microbial investments in C (length, and N and P (angle acquiring enzymes. Shorter lengths on day 3 suggested low C limitation, whereas greater lengths on day 14 suggested an increase in C limitation with decay. The soils and litter in this study generally had stronger P limitation (angles > 45˚. Reductions in vector angles to < 45˚ for sand by day 14 suggested a shift to N limitation. These relational variables inform enzyme-based models, and are usually much less ambiguous when obtained from a single study in which measurements were made on the same samples than when extrapolated from separate studies.

  14. pH-sensitive pHluorins as a molecular sensor for in situ monitoring of enzyme-catalyzed prodrug activation.

    Science.gov (United States)

    Liu, Hui; Cao, Xiaodan; Wang, Ping; Ma, Xingyuan

    2017-07-01

    This work examines the feasibility of using a pH-sensitive fluorescent protein as a molecular reporter for enzyme-catalyzed prodrug activation reaction. Specifically, a ratiometric pHluorins was examined for detection of the activity of horseradish peroxidase (HRP) for the activation of indole-3-acetic acid. The pHluorins and HRP were conjugated chemically, forming a biocatalyst with a self-reporting function. Results showed that the characteristic fluorescence intensity ratio of the conjugate shifted from 1.47 to 1.40 corresponding to the progress of the prodrug activation reaction. The effectiveness of applying the conjugate for inhibition of the growth of Bcap-37 cells was also demonstrated simultaneously with reaction monitoring. The results reveal a very promising approach to realizing in situ monitoring of enzyme activities based on pH shifting for enzyme-based prodrug therapy applications. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  15. Different responses of tobacco antioxidant enzymes to light and chilling stress

    NARCIS (Netherlands)

    Gechev, T; Willekens, H; Van Montagu, M; Inze, D; Van Camp, W; Toneva, [No Value; Minkov, [No Value

    The effect of elevated light treatment (25 degreesC, PPFD 360 mumol m(-2) sec(-1)) or chilling temperatures combined with elevated light (5 degreesC, PPFD 360 mumol m-2 sec-1) on the activity of six antioxidant enzymes, guaiacol peroxidases, and glutathione peroxidase (GPx, EC 1.11.1.9) protein

  16. A peroxidase related to the mammalian antimicrobial protein myeloperoxidase in the Euprymna-Vibrio mutualism.

    Science.gov (United States)

    Weis, V M; Small, A L; McFall-Ngai, M J

    1996-11-26

    Many animal-bacteria cooperative associations occur in highly modified host organs that create a unique environment for housing and maintaining the symbionts. It has been assumed that these specialized organs develop through a program of symbiosis-specific or -enhanced gene expression in one or both partners, but a clear example of this process has been lacking. In this study, we provide evidence for the enhanced production of an enzyme in the symbiotic organ of the squid Euprymna scolopes, which harbors a culture of the luminous bacterium Vibrio fischeri. Our data show that this enzyme has a striking biochemical similarity to mammalian myeloperoxidase (MPO; EC 1.11.17), an antimicrobial dianisidine peroxidase that occurs in neutrophils. MPO and the squid peroxidase catalyze the same reaction, have similar apparent subunit molecular masses, and a polyclonal antibody to native human MPO specifically localized a peroxidase-like protein to the bacteria-containing regions of the symbiotic organ. We also provide evidence that a previously described squid cDNA encodes the protein (LO4) that is responsible for the observed dianisidine peroxidase activity. An antibody made against a fragment of LO4 immunoprecipiated dianisidine peroxidase activity from extracts of the symbiotic organ, and reacted against these extracts and human MPO in Western blot analysis. These data suggest that related biochemical mechanisms for the control of bacterial number and growth operate in associations that are as functionally diverse as pathogenesis and mutualism, and as phylogenetically distant as molluscs and mammals.

  17. Inhibition of existing denitrification enzyme activity by chloramphenicol

    Science.gov (United States)

    Brooks, M.H.; Smith, R.L.; Macalady, D.L.

    1992-01-01

    Chloramphenicol completely inhibited the activity of existing denitrification enzymes in acetylene-block incubations with (i) sediments from a nitrate-contaminated aquifer and (ii) a continuous culture of denitrifying groundwater bacteria. Control flasks with no antibiotic produced significant amounts of nitrous oxide in the same time period. Amendment with chloramphenicol after nitrous oxide production had begun resulted in a significant decrease in the rate of nitrous oxide production. Chloramphenicol also decreased (>50%) the activity of existing denitrification enzymes in pure cultures of Pseudomonas denitrificans that were harvested during log- phase growth and maintained for 2 weeks in a starvation medium lacking electron donor. Short-term time courses of nitrate consumption and nitrous oxide production in the presence of acetylene with P. denitrificans undergoing carbon starvation were performed under optimal conditions designed to mimic denitrification enzyme activity assays used with soils. Time courses were linear for both chloramphenicol and control flasks, and rate estimates for the two treatments were significantly different at the 95% confidence level. Complete or partial inhibition of existing enzyme activity is not consistent with the current understanding of the mode of action of chloramphenicol or current practice, in which the compound is frequently employed to inhibit de novo protein synthesis during the course of microbial activity assays. The results of this study demonstrate that chloramphenicol amendment can inhibit the activity of existing denitrification enzymes and suggest that caution is needed in the design and interpretation of denitrification activity assays in which chloramphenicol is used to prevent new protein synthesis.

  18. Activity of selected hydrolytic enzymes in Allium sativum L. anthers.

    Science.gov (United States)

    Winiarczyk, Krystyna; Gębura, Joanna

    2016-05-01

    The aim of the study was to determine enzymatic activity in sterile Allium sativum anthers in the final stages of male gametophyte development (the stages of tetrads and free microspores). The analysed enzymes were shown to occur in the form of numerous isoforms. In the tetrad stage, esterase activity was predominant, which was manifested by the greater number of isoforms of the enzyme. In turn, in the microspore stage, higher numbers of isoforms of acid phosphatases and proteases were detected. The development of sterile pollen grains in garlic is associated with a high level of protease and acid phosphatase activity and lower level of esterase activities in the anther locule. Probably this is the first description of the enzymes activity (ACPH, EST, PRO) in the consecutives stages of cell wall formation which is considered to be one of the causes of male sterility in flowering plant. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Activity of certain enzymes in cadmium-poisoned chicks

    Energy Technology Data Exchange (ETDEWEB)

    Kench, J E; Gubb, P J.D.

    1970-01-01

    Activities of a number of enzymes in the liver and other tissues of newly hatched cadmium poisoned chicks have been compared with those of normal controls before and after incubation with Cd/sup +2/ at a concentration similar to that present in vivo. Concentrations of Cd/sup +2/ in the various cellular fractions were determined, after wet oxidation, by atomic absorption spectrophotometry. Interaction of Cd/sup +2/ with enzymes may provide information on the localization of enzymes within mitochondria and other cellular structures. 7 references.

  20. Musa paradisiaca stem juice as a source of peroxidase and ligninperoxidase.

    Science.gov (United States)

    Vernwal, S K; Yadav, R S; Yadav, K D

    2000-10-01

    Musa paradisiaca stem juice has been shown to contain peroxidase activity of the order of 0.1 enzyme unit/ml. The Km values of this peroxidase for the substrates guaiacol and hydrogen peroxide are 2.4 and 0.28 mM respectively. The pH and temperature optima are 4.5 and 62.5 degrees C respectively. Like other peroxidases, it follows double displacement type mechanism. At low pH, Musa paradisiaca stem juice exhibits ligninperoxidase type activity. The pH optimum for ligninperoxidase type activity is 2.0 and the temperature optimum is 24 degrees C. The Km values for veratryl alcohol and n-propanol are 66 and 78 microM respectively.

  1. Tissue and plasma enzyme activities in juvenile green iguanas.

    Science.gov (United States)

    Wagner, R A; Wetzel, R

    1999-02-01

    To determine activities of intracellular enzymes in 8 major organs in juvenile green iguanas and to compare tissue and plasma activities. 6 green iguanas iguanas, but high values may not always indicate overt muscle disease. The AMS activity may be specific for the pancreas, but the wide range of plasma activity would likely limit its diagnostic usefulness. Activities of AST and LDH may reflect tissue damage or inflammation, but probably do not reflect damage to specific tissues or organs.

  2. Effect of cadmium and zinc on antioxidant enzyme activity in the gastropod, Achatina fulica.

    Science.gov (United States)

    Chandran, Rashmi; Sivakumar, A A; Mohandass, S; Aruchami, M

    2005-01-01

    Heavy metal stress results in the production of O(2)(.-), H(2)O(2) and (.)OH, which affect various cellular processes, mostly the functioning of membrane systems. Cells are normally protected against free oxyradicals by the operation of intricate antioxidant systems. The aim of the present work is to examine the effect of CdCl(2) and ZnSO(4) on antioxidative enzyme activity in the gastropod, Achatina fulica. The concentrations of antioxidant enzymes--superoxide dismutase (SOD), catalase (Cat) and glutathione peroxidase (GPx)--and nonenzymatic antioxidants--glutathione and vitamin-C--were found to be decreased in both digestive gland and kidney of the gastropod, Achatina fulica treated with individual concentrations of 0.5 ppm and 1ppm of CdCl(2) and ZnSO(4), compared to that of control animals. Based on the above study, it is evident that Achatina fulica can be used as a bioindicator to monitor the environmental heavy metal pollution.

  3. Chimeric enzymes with improved cellulase activities

    Science.gov (United States)

    Xu, Qi; Baker, John O; Himmel, Michael E

    2015-03-31

    Nucleic acid molecules encoding chimeric cellulase polypeptides that exhibit improved cellulase activities are disclosed herein. The chimeric cellulase polypeptides encoded by these nucleic acids and methods to produce the cellulases are also described, along with methods of using chimeric cellulases for the conversion of cellulose to sugars such as glucose.

  4. Enzyme inhibitory activity of selected Philippine plants

    International Nuclear Information System (INIS)

    Sasotona, Joseph S.; Hernandez, Christine C.

    2015-01-01

    In the Philippines, the number one cause of death are cardiovascular diseases. Diseases linked with inflammation are proliferating. This research aims to identify plant extracts that have potential activity of cholesterol-lowering, anti-hypertension, anti-gout, anti-inflammatory and fat blocker agents. Although there are commercially available drugs to treat the aforementioned illnesses, these medicine have adverse side-effects, aside from the fact that they are expensive. The results of this study will serve as added knowledge to contribute to the development of cheaper, more readily available, and effective alternative medicine. 100 plant extracts from different areas in the Philippines have been tested for potential inhibitory activity against Hydroxymethylglutaryl-coenzyme A (HMG-CoA), Lipoxygenase, and Xanthine Oxidase. The plant samples were labeled with codes and distributed to laboratories for blind testing. The effective concentration of the samples tested for Xanthine oxidase is 100 ppm. Samples number 9, 11, 14, 29, 43, 46, and 50 have shown significant inhibitory activity at 78.7%, 78.4%, 70%, 89.2%, 79%, 67.4%, and 67.5% respectively. Samples tested for Lipoxygenase inhibition were set at 33ppm. Samples number 2, 37, 901, 1202, and 1204 have shown significant inhibitory activity at 66, 84.9%, 88.55%, 93.3%, and 84.7% respectively. For HMG-CoA inhibition, the effective concentration of the samples used was 100 ppm. Samples number 1 and 10 showed significant inhibitory activity at 90.1% and 81.8% respectively. (author)

  5. Histochemical location of key enzyme activities involved in receptivity and self-incompatibility in the olive tree (Olea europaea L.).

    Science.gov (United States)

    Serrano, Irene; Olmedilla, Adela

    2012-12-01

    Stigma-surface and style enzymes are important for pollen reception, selection and germination. This report deals with the histochemical location of the activity of four basic types of enzyme involved in these processes in the olive (Olea europaea L.). The detection of peroxidase, esterase and acid-phosphatase activities at the surface of the stigma provided evidence of early receptivity in olive pistils. The stigma maintained its receptivity until the arrival of pollen. Acid-phosphatase activity appeared in the style at the moment of anthesis and continued until the fertilization of the ovule. RNase activity was detected in the extracellular matrix of the styles of flowers just before pollination and became especially evident in pistils after self-pollination. This activity gradually decreased until it practically disappeared in more advanced stages. RNase activity was also detected in pollen tubes growing in pollinated pistils and appeared after in vitro germination in the presence of self-incompatible pistils. These findings suggest that RNases may well be involved in intraspecific pollen rejection in olive flowers. To the best of our knowledge this is the first time that evidence of enzyme activity in stigma receptivity and pollen selection has been described in this species. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  6. Extraction of Active Enzymes from "Hard-to-Break-Cells"

    DEFF Research Database (Denmark)

    Ottaviani, Alessio; Tesauro, Cinzia; Fjelstrup, S

    We present the utilization of a rolling circle amplification (RCA) based assay to investigate the extraction efficiency of active enzymes from a class of “hard-to-break” cells, yeast Saccaramyces cerevisiae. Current analyses of microorganisms, such as pathogenic bacteria, parasites or particular...... life stages of microorganisms (e.g. spores from bacteria or fungi) is hampered by the lack of efficient lysis protocols that preserve the activity and integrity of the cellular content. Presented herein is a flexible scheme to screen lysis protocols for active enzyme extraction. We also report a gentle...... yet effective approach for extraction of active enzymes by entrapping cells in microdroplets. Combined effort of optimized extraction protocols and effective analytical approaches is expected to generate impact in future disease diagnosis and environmental safety....

  7. Erythrocytic glutathione peroxidase: Its relationship to plasma selenium in man

    International Nuclear Information System (INIS)

    Perona, G.; Cellerino, R.; Guidi, G.C.; Moschini, G.; Stievano, B.M.; Tregnaghi, C.

    1977-01-01

    Erythrocytic glutathione-peroxidase (GSH-Px) activity and plasma selenium concentrations were measured in 14 patients: 7 with iron deficiency and 7 with raised serum iron levels. The decreased enzymatic activity in iron deficiency was confirmed. Plasma selenium was significantly lower in patients with lower serum iron; furthermore there is a significant correlation between serum iron and plasma selenium concentrations. Another correlation even more significant was found between plasma selenium and enzyme activity in all the cases we studied. These data suggests that the importance of iron for GSH-Px activity may be merely due to its relationship with selenium and that plasma selenium concentration may be of critical importance for enzyme activity. (author)

  8. Catalytic and peroxidase-like activity of carbon based-AuPd bimetallic nanocomposite produced using carbon dots as the reductant

    International Nuclear Information System (INIS)

    Yang, Liuqing; Liu, Xiaoying; Lu, Qiujun; Huang, Na; Liu, Meiling; Zhang, Youyu; Yao, Shouzhuo

    2016-01-01

    In this report, carbon-based AuPd bimetallic nanocomposite (AuPd/C NC) was synthesized using carbon dots (C-dots) as the reducing agent and stabilizer by a simple green sequential reduction strategy, without adding other agents. The as synthesized AuPd/C NC showed good catalytic activity and peroxidase-like property. The structure and morphology of these nanoparticles were clearly characterized by UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The AuPd/C NC catalyst exhibits noticeably higher catalytic activity than Pd and Au nanoparticles in catalysis reduction of 4-nitrophenol (4-NP). Moreover, based on the high peroxidase-like property of AuPd/C NC, a new colorimetric detection method for hydrogen peroxide (H 2 O 2 ) has been designed using 3,3′,5,5′-tetramethyl-benzidine (TMB) as the substrate, which provides a simple and sensitive means to detect H 2 O 2 in wide linear range of 5 μM–500 μM and 500 μM–4 mM with low detection limit of 1.6 μM (S/N = 3). Therefore, the facile synthesis strategy for bimetallic nanoparticles by the mild reductant of carbon dot will provide some new thoughts for preparing of carbon-based metal nanomaterials and expand their application in catalysis and analytical chemistry areas. - Highlights: • Carbon-based AuPd bimetallic nanocomposite was synthesized using carbon dots. • The green sequential reduction strategy synthesis method is simple, green, convenient and effective. • The as synthesized AuPd/C NC showed good catalytic activity and peroxidase-like activity. • The AuPd/C NC exhibits noticeably higher catalytic activity in reduction of 4-nitrophenol. • A new colorimetric detection method for hydrogen peroxide based on AuPd/C NC was proposed.

  9. [Isolation and purification of Mn-peroxidase from Azospirillum brasilense Sp245].

    Science.gov (United States)

    Kupriashina, M A; Selivanov, N Iu; Nikitina, V E

    2012-01-01

    Homogenous Mn-peroxidase of a 26-fold purity grade was isolated from a culture of Azospirillum brasilense Sp245 cultivated on a medium containing 0.1 mM pyrocatechol. The molecular weight of the enzyme is 43 kD as revealed by electrophoresis in SDS-PAAG. It was shown that the use of pyrocatechol and 2,2'-azino-bis(3-ethylbenzotiazoline-6-sulfonate) at concentrations of 0.1 and I mM as inductors increased the Mn-peroxidase activity by a factor of 3.

  10. Patterns of functional enzyme activity in fungus farming ambrosia beetles

    Directory of Open Access Journals (Sweden)

    De Fine Licht Henrik H

    2012-06-01

    Full Text Available Abstract Introduction In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae, wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. Results We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Conclusion Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily

  11. Patterns of functional enzyme activity in fungus farming ambrosia beetles.

    Science.gov (United States)

    De Fine Licht, Henrik H; Biedermann, Peter H W

    2012-06-06

    In wood-dwelling fungus-farming weevils, the so-called ambrosia beetles (Curculionidae: Scolytinae and Platypodinae), wood in the excavated tunnels is used as a medium for cultivating fungi by the combined action of digging larvae (which create more space for the fungi to grow) and of adults sowing and pruning the fungus. The beetles are obligately dependent on the fungus that provides essential vitamins, amino acids and sterols. However, to what extent microbial enzymes support fungus farming in ambrosia beetles is unknown. Here we measure (i) 13 plant cell-wall degrading enzymes in the fungus garden microbial consortium of the ambrosia beetle Xyleborinus saxesenii, including its primary fungal symbionts, in three compartments of laboratory maintained nests, at different time points after gallery foundation and (ii) four specific enzymes that may be either insect or microbially derived in X. saxesenii adult and larval individuals. We discovered that the activity of cellulases in ambrosia fungus gardens is relatively small compared to the activities of other cellulolytic enzymes. Enzyme activity in all compartments of the garden was mainly directed towards hemicellulose carbohydrates such as xylan, glucomannan and callose. Hemicellulolytic enzyme activity within the brood chamber increased with gallery age, whereas irrespective of the age of the gallery, the highest overall enzyme activity were detected in the gallery dump material expelled by the beetles. Interestingly endo-β-1,3(4)-glucanase activity capable of callose degradation was identified in whole-body extracts of both larvae and adult X. saxesenii, whereas endo-β-1,4-xylanase activity was exclusively detected in larvae. Similar to closely related fungi associated with bark beetles in phloem, the microbial symbionts of ambrosia beetles hardly degrade cellulose. Instead, their enzyme activity is directed mainly towards comparatively more easily accessible hemicellulose components of the ray

  12. Characteristics of estrogen-induced peroxidase in mouse uterine luminal fluid

    International Nuclear Information System (INIS)

    Jellinck, P.H.; Newbold, R.R.; McLachlan, J.A.

    1991-01-01

    Peroxidase activity in the uterine luminal fluid of mice treated with diethylstilbestrol was measured by the guaiacol assay and also by the formation of 3H2O from [2-3H]estradiol. In the radiometric assay, the generation of 3H2O and 3H-labeled water-soluble products was dependent on H2O2 (25 to 100 microM), with higher concentrations being inhibitory. Tyrosine or 2,4-dichlorophenol strongly enhanced the reaction catalyzed either by the luminal fluid peroxidase or the enzyme in the CaCl2 extract of the uterus, but decreased the formation of 3H2O from [2-3H]estradiol by lactoperoxidase in the presence of H2O2 (80 microM). NADPH, ascorbate, and cytochrome c inhibited both luminal fluid and uterine tissue peroxidase activity to the same extent, while superoxide dismutase showed a marginal activating effect. Lactoferrin, a major protein component of uterine luminal fluid, was shown not to contribute to its peroxidative activity, and such an effect by prostaglandin synthase was also ruled out. However, it was not possible to exclude eosinophil peroxidase, brought to the uterus after estrogen stimulation, as being the source of peroxidase activity in uterine luminal fluid

  13. Early bichemical markers of effects: Enzyme induction, oncogene activation and markers of oxidative damage

    DEFF Research Database (Denmark)

    Poulsen, Henrik E.; Loft, Steffen

    1995-01-01

    Early bichemical marker, enzyme induction, oncogene activation, oxidative damage, low-density lipoprotein......Early bichemical marker, enzyme induction, oncogene activation, oxidative damage, low-density lipoprotein...

  14. Expression, purification and characterization of a peroxidase from ...

    African Journals Online (AJOL)

    Peroxidase is one of the key enzymes of the cellular antioxidant defense system, which is mostly involved in the reduction of hydrogen peroxide. Here, a peroxidase gene, named ThPOD1 was isolated from a cDNA library, which was generated from root tissue of Tamarix hispida that was exposed to 0.4 M NaCl. The cDNA ...

  15. Lead action on activity of some enzymes of plants

    International Nuclear Information System (INIS)

    Korolyov, A.N.; Koshkaryova, A.I.

    2008-01-01

    Lead action on activity of some enzymes of young plants of barley double-row (Hordeum distichon L.) families of cereals (Grominea). It is established that activity urease, catalase, ascorbatoxidase is in dependence as from a lead dose in a nutritious solution, and term ontogenesis. At later stages ontogenesis the increase in concentration of lead in an inhabitancy leads to sharp decrease in activity ascorbatoxidase. In the same conditions activity urease and catalase raises.

  16. Evolutionary transitions in enzyme activity of ant fungus gardens.

    Science.gov (United States)

    De Fine Licht, Henrik H; Schiøtt, Morten; Mueller, Ulrich G; Boomsma, Jacobus J

    2010-07-01

    Fungus-growing (attine) ants and their fungal symbionts passed through several evolutionary transitions during their 50 million year old evolutionary history. The basal attine lineages often shifted between two main cultivar clades, whereas the derived higher-attine lineages maintained an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens are targeted primarily toward partial degradation of plant cell walls, reflecting a plesiomorphic state of nondomesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major breakdown of cell walls. The adaptive significance of the lower-attine symbiont shifts remains unclear. One of these shifts was obligate, but digestive advantages remained ambiguous, whereas the other remained facultative despite providing greater digestive efficiency.

  17. Occurrence and properties of Petunia peroxidase a

    NARCIS (Netherlands)

    Hendriks, T.

    1989-01-01

    Peroxidases are probably the most extensively studied enzymes in higher plants. Various isoenzymes occur as soluble proteins in the apoplast and in the vacuole, or are bound to membranes and cell walls. Their occurrence is often organ-specific and developmentally controlled, and there is

  18. Thyroid peroxidase autoantibodies in euthyroid subjects

    NARCIS (Netherlands)

    Prummel, Mark F.; Wiersinga, Wilmar M.

    2005-01-01

    Thyroid peroxidase (TPO) is a key enzyme in the formation of thyroid hormones and a major autoantigen in autoimmune thyroid diseases. Titers of TPO antibodies also correlate with the degree of lymphocytic infiltration in euthyroid subjects, and they are frequently present in euthyroid subjects

  19. EFFECTS OF CIGARETTE SMOKING ON ERYTHROCYTE ANTIOXIDATIVE ENZYME ACTIVITIES AND PLASMA CONCENTRATIONS OF THEIR COFACTORS

    Directory of Open Access Journals (Sweden)

    M. Zahraie

    2005-07-01

    Full Text Available Tobacco smoke contains numerous compounds, many ‎of which are oxidants and capable of producing free radical and enhancing ‎the oxidative stress. The aim of this study was to investigate the effect of cigarette smoking on the erythrocyte antioxidative enzyme activities and the plasma ‎concentration of their cofactors. ‎Sixty eight healthy men were enrolled, 32 of whom had never smoked and 36 had smoked at least 10 cigarettes per day for ‎at least one year. Hemolysate superoxide dismutase (Cu-Zn SOD, glutathione peroxidase (GSH-Px and ‎catalase (CAT activities were measured using spectrophotometer. Plasma copper, zinc and selenium concentrations were determined ‎using atomic absorption spectrophotometer. Plasma iron concentration was determined by colorimetric ‎method. We found that erythrocyte Cu-Zn SOD activity was significantly higher in tobacco smokers ‎compared with non-smokers (1294 ± 206.7 U/gHb in smokers vs. 1121.6 ± 237.8 U/gHb in non-‎smokers, P < 0.01. While plasma selenium concentration was significantly lower in tobacco ‎smokers (62.7±14.8 μg/L in smokers vs. 92.1 ± 17.5 μg/L in non-smokers, P < 0.01, there were no significant ‎differences in erythrocyte GSH-Px and CAT activities and plasma copper, zinc and iron concentrations between the two groups. ‎It seems that cigarette smoking can alter antioxidative enzymes activity and plasma concentration of some trace elements.

  20. The 28-day exposure to fenpropathrin decreases locomotor activity and reduces activity of antioxidant enzymes in mice brains.

    Science.gov (United States)

    Nieradko-Iwanicka, Barbara; Borzęcki, Andrzej

    2016-04-01

    Fenpropathrin (Fen) is a pyrethroid (Pyr) insecticide. Pyrs are used in veterinary medicine, in agriculture and for domestic purposes. As their use increases, new questions about their side effects and mode of action in non-target organisms arise. The objective of this work was to characterize dose-response relationship for in vivo motor function and memory in mice exposed to Fen for 28 days and to assess its influence on activity of antioxidant enzymes in mice brains. The experiment was performed using 64 female mice. Fen at the dose of 11.9mg/kg of body mass, 5.95mg/kg or 2.38mg/kg was administered ip to the mice for 28 consecutive days. Motor function and spatial working memory were tested on days 7, 14 and 28. On day 29, the animals were sacrificed and brains were used to determine activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Fen significantly decreased locomotor activity in mice receiving the highest dose at every stage of the experiment. Lower doses reduced locomotion on days 7 and 14. Fen did not produce memory impairment. A decrease in activities of SOD and GPx was recorded in mice brains. The decrease of SOD activity in mice brains results from direct inhibition of the enzyme by Fen and/or increased utilization due to excessive free radical formation in conditions of Fen-induced oxidative stress. The reduction in GPx activity is probably due to limited glutathione availability. The reduced locomotor activity is a behavioral demonstration of Fen-induced damage in the dopaminergic system. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  1. Antisense Suppression of 2-Cysteine Peroxiredoxin in Arabidopsis Specifically Enhances the Activities and Expression of Enzymes Associated with Ascorbate Metabolism But Not Glutathione Metabolism1

    Science.gov (United States)

    Baier, Margarete; Noctor, Graham; Foyer, Christine H.; Dietz, Karl-Josef

    2000-01-01

    The aim of this study was to characterize the effect of decreased 2-cysteine peroxiredoxin (2-CP) on the leaf anti-oxidative system in Arabidopsis. At three stages of leaf development, two lines of transgenic Arabidopsis mutants with decreased contents of chloroplast 2-CP were compared with wild type and a control line transformed with an empty vector. Glutathione contents and redox state were similar in all plants, and no changes in transcript levels for enzymes involved in glutathione metabolism were observed. Transcript levels for chloroplastic glutathione peroxidase were much lower than those for 2-CP, and both cytosolic and chloroplastic glutathione peroxidase were not increased in the mutants. In contrast, the foliar ascorbate pool was more oxidized in the mutants, although the difference decreased with plant age. The activities of thylakoid and stromal ascorbate peroxidase and particularly monodehydroascorbate reductase were increased as were transcripts for these enzymes. No change in dehydroascorbate reductase activity was observed, and effects on transcript abundance for glutathione reductase, catalase, and superoxide dismutase were slight or absent. The results demonstrate that 2-CP forms an integral part of the anti-oxidant network of chloroplasts and is functionally interconnected with other defense systems. Suppression of 2-CP leads to increased expression of other anti-oxidative genes possibly mediated by increased oxidation state of the leaf ascorbate pool. PMID:11027730

  2. Intrinsic peroxidase-like catalytic activity of nitrogen-doped graphene quantum dots and their application in the colorimetric detection of H2O2 and glucose

    International Nuclear Information System (INIS)

    Lin, Liping; Song, Xinhong; Chen, Yiying; Rong, Mingcong; Zhao, Tingting; Wang, Yiru; Jiang, Yaqi; Chen, Xi

    2015-01-01

    Highlights: • The highly intrinsic peroxidase-like catalytic activity of N-GQDs is revealed. • The activity of N-GQDs depended on pH, temperature and H 2 O 2 concentration. • The activity of N-GQDs has been used to the detection of H 2 O 2 and glucose. • This assay was suitable for the detection of glucose concentrations in real samples. - Abstract: In this paper, the highly intrinsic peroxidase-like catalytic activity of nitrogen-doped graphene quantum dots (N-GQDs) is revealed. This activity was greatly dependent on pH, temperature and H 2 O 2 concentration. The experimental results showed that the stable N-GQDs could be used for the detection of H 2 O 2 and glucose over a wide range of pH and temperature, offering a simple, highly selective and sensitive approach for their colorimetric sensing. The linearity between the analyte concentration and absorption ranged from 20 to 1170 μM for H 2 O 2 and 25 to 375 μM for glucose with a detection limit of 5.3 μM for H 2 O 2 and 16 μM for glucose. This assay was also successfully applied to the detection of glucose concentrations in diluted serum and fruit juice samples

  3. Acinetobacter calcoaceticus CSY-P13 Mitigates Stress of Ferulic and p-Hydroxybenzoic Acids in Cucumber by Affecting Antioxidant Enzyme Activity and Soil Bacterial Community

    Directory of Open Access Journals (Sweden)

    Fenghui Wu

    2018-06-01

    Full Text Available Ferulic acid (FA and p-hydroxybenzoic acid (PHBA are main phenolic compounds accumulated in rhizosphere of continuously cropped cucumber, causing stress in plants. Microbial degradation of a mixture of FA and PHBA is not well understood in soil. We isolated a strain CSY-P13 of Acinetobacter calcoaceticus, inoculated it into soil to protect cucumber from FA and PHBA stress, and explored a mechanism underlying the protection. CSY-P13 effectively degraded a mixture of FA and PHBA in culture solution under conditions of 39.37°C, pH 6.97, and 21.59 g L-1 potassium dihydrogen phosphate, giving rise to 4-vinyl guaiacol, vanillin, vanillic acid, and protocatechuic acid. During FA and PHBA degradation, activities of superoxide dismutase (SOD, catalase, ascorbate peroxidase, and dehydroascorbate reductase in CSY-P13 were induced. Inoculated into cucumber-planted soil containing 220 μg g-1 mixture of FA and PHBA, CSY-P13 degraded FA and PHBA in soil, increased plant height, and decreased malonaldehyde, superoxide radical, and hydrogen peroxide levels in leaves. CSY-P13 also enhanced SOD, guaiacol peroxidase, catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activities; increased ascorbate and glutathione contents; and elevated transcript levels of copper/zinc SOD, manganese SOD, and catalase in leaves under FA and PHBA. Moreover, CSY-P13 increased phosphatase, catalase, urease, and sucrase activities and changed bacterial richness, diversity, and community composition by high throughput sequencing in cucumber-planted soil supplemented with the mixture of FA and PHBA. So CSY-P13 degrades the mixture of FA and PHBA in soil and mitigates stress from the two phenolic compounds in cucumber by activating antioxidant enzymes, changing soil bacterial community, and inducing soil enzymes.

  4. Enzyme activities in reclaimed coal mine spoils and soils

    Energy Technology Data Exchange (ETDEWEB)

    Fresquez, P R; Aldon, E F; Lindemann, W C

    1987-11-01

    The segregation and stockpiling of topsoil material may reduce enzymatic activities that may hinder normal nutrient cycling processes in reclaimed minelands. The effects of topsoiling and reclamation age on dehydrogenase, nitrogenase, phosphatase, arylsulphatase, amylase, cellulase, invertase and urease activities were evaluated on three reclaimed non-top-soiled and five reclaimed topsoiled areas and compared with an indisturbed reference soil. Three months after topsoiling and revegetation, activities of the enzymes in the reclaimed areas, with the exception of dehydrogenase, were statistically equal to activities of the undisturbed soil. Most enzymes, including dehydrogenase, peaked in the next 1 or 2 years after reclamation with topsoiling and declined thereafter. A 4-year-old topsoiled site (revegetated in 1978) was statistically similar to the undisturbed soil. Amylase activity, however, was significantly lower after the fourth year compared to the undisturbed soil. The non-topsoiled areas, even after 6, 7 and 8 years, appeared to have lower enzyme activities than the younger topsoiled areas or the undisturbed soil. This trend was supported by the finding that the 4-year-old topsoiled site was more enzymatically similar to the undisturbed soil than was the 8-year-old non-topsoiled site (revegetated in 1974). The low enzyme acitivities found in the non-topsoiled areas may be a result of their adverse chemical and physical properties, as well as the low diversity of microorganisms. These studies demonstrate the value of topsoil use for early establishment of soil processes in reclaimed areas. 3 figs., 19 refs., 8 tabs.

  5. Biological energy from the igneous rock enhances cell growth and enzyme activity

    International Nuclear Information System (INIS)

    Lin Y.-L.; Kuo, H.-S; Chen, C.-T.; Kuo, S.-C.

    2000-01-01

    Some effects from natural resources might be ignored and unused by humans. Environmental hormesis could be a phenomena necessary to bio-organism existence on earth. Since 1919, radiation and some heavy metal hormesis from the environment were proved in various reports. In this study, igneous rock with very low radioactivity and high ferrous activity was measured by multichannel analyzer and inductively coupled plasma analyzer. The water treated by igneous rock, both directly soaked or indirectly in contact, induced increased activities of glucose oxidase, catalase, peroxidase, and superoxide dismutase. It also increased cell growth of SC-M1, HCT-15, Raji, and fibroblast cell lines. The water after treatment of igneous rock had no change in pH values, but displayed decreased conductivity values. We assume that the igneous rock could transfer energy to water to change the molecular structure or conformation of water cluster, or by radiation hormesis effect could then induce increased enzyme activity and cell growth. It is also possible that the energy from rock may combine radiation hormesis with other transferable biological energy forms to change water cluster conformation

  6. AM Fungi Influences the Photosynthetic Activity, Growth and Antioxidant Enzymes in Allium sativum L. under Salinity Condition

    Directory of Open Access Journals (Sweden)

    Mahesh BORDE

    2010-12-01

    Full Text Available Potential of Arbuscular mycorrhizal (AM fungi in alleviating adverse salt effects on growth was tested in garlic (Allium sativum L.. Towards this objective we analyzed the AM root colonization and the activities of various antioxidant enzymes like peroxidase, catalase, and superoxide dismutase at 0, 100, 200 and 300 mM salinity levels. The activities of all the antioxidant enzymes studied were found to be increased in AM garlic plants. Antioxidant activity was maximum in 100 and 200 mM NaCl (sodium chloride in AM and non-AM plants. Proline accumulation was induced by salt levels and it was more in leaves as well as roots of AM plants as compared to non-AM plants, this indicating that mycorrhiza reduced salt injury. Growth parameters of garlic plants like leaf area, plant fresh and dry weight and antioxidant enzyme activities were higher at moderate salinity level. This work suggests that the mycorrhiza helps garlic plants to perform better under moderate salinity level by enhancing the antioxidant activity and proline content as compared to non-AM plants.

  7. Actinomycete enzymes and activities involved in straw saccharification

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, A J; Ball, A S [Liverpool Univ. (UK). Dept. of Genetics and Microbiology

    1990-01-01

    This research programme has been directed towards the analysis of actinomycete enzyme systems involved in the degradation of plant biomass (lignocellulose.) The programme was innovative in that a novel source of enzymes was systematically screened and wheat straw saccharifying activity was the test criterion. Over 200 actinomycete strains representing a broad taxonomic range were screened. A range of specific enzyme activities were involved and included cellulase, xylanase, arabinofuranosidase, acetylesterase, {beta}-xylosidase and {beta}-glucosidase. Since hemicellulose (arabinoxylan) was the primary source of sugar, xylanases were characterized. The xylan-degrading systems of actinomycetes were complex and nonuniform, with up to six separate endoxylanases identified in active strains. Except for microbispora bispora, actinomycetes were found to be a poor source of cellulase activity. Evidence for activity against the lignin fraction of straw was produced for a range of actinomycete strains. While modification reactions were common, cleavage of inter-monomer bonds, and utilization of complex polyphenolic compounds were restricted to two strains: Thermomonospora mesophila and Streptomyces badius. Crude enzyme preparations from actinomycetes can be used to generate sugar, particularly pentoses, directly from cereal straw. The potential for improvements in yield rests with the formulation to cooperative enzyme combinations from different strains. The stability properties of enzymes from thermophilic strains and the general neutral to alkali pH optima offer advantages in certain process situations. Actinomycetes are a particularly rich source of xylanases for commercial application and can rapidly solubilise a lignocarbohydrate fraction of straw which may have both product and pretreatment potential. 31 refs., 4 figs., 5 tabs.

  8. Double Antibody EIA of Cortisol Using Peroxidase As Label

    International Nuclear Information System (INIS)

    Karim, F.M.; Hamad, A.W.R.; Hashim, A.M.

    1998-01-01

    An enzyme immunoassay (EIA) technique for plasma cortisol was established by using cortisol-3 (carboxymethyl) oxime covalently linked to the horseradish peroxidase as the label. An antibody raised in the rabbits against cortisol-3-(carboxy-methyl) oxime-bovline serum albumin was used as the first anti-body. Sheep anti-rabbit gamma-globulin serum with 8 percent poly-ethyleneglycol were used to separate antibody-bound and free cortisol. The enzyme activity of the bound fraction was measured with ortho-phenylene diamine as substrate. The procedure performed at room temperature was evaluated by sensitivity (50 pg/ tube). The correlation coefficient between our enzyme immunoassay technique and radioimmunoassay technique for determination of plasma cortisol was 97 percent

  9. Influence of long-term fertilization on soil enzyme activities

    Directory of Open Access Journals (Sweden)

    Alina Dora SAMUEL

    2009-05-01

    Full Text Available Soil enzyme activities (actual and potential dehydrogenase, catalase, acid and alkaline phosphatase were determined in the 0–10, 10–20, and 20–30 cm layers of a brown luvic soil submitted to a complex fertilization experiment with different types of green manure. It was found that each activity decreased with increasing sampling depth. It should be emphasized that greenmanuring of maize led to a significant increase in each of the five enzymatic activities determined. The enzymatic indicators of soil quality calculated from the values of enzymatic activities showed the order: lupinus + rape + oat > lupinus > vetch + oat + ryegrass > lupinus + oat + vetch > unfertilized plot. This order means that by determination of enzymatic activities valuable information can be obtained regarding fertility status of soils. There were significant correlations of soil enzyme activities with chemical properties.

  10. Functionalization of PDMS modified and plasma activated two-component polyurethane coatings by surface attachment of enzymes

    International Nuclear Information System (INIS)

    Kreider, Alexej; Richter, Katharina; Sell, Stephan; Fenske, Mandus; Tornow, Christian; Stenzel, Volkmar; Grunwald, Ingo

    2013-01-01

    This article describes a new strategy for coupling the enzyme horseradish peroxidase to a two-component polyurethane (2C-PUR) coating. A stable polymer conjugate was achieved by combining the enzyme and the 2C-PUR coating which was modified with poly(dimethylsiloxane) (PDMS), located at the surface. An atmospheric pressure plasma jet system was used to convert alkyl groups from the PDMS into polar silanol functionalities. This conversion was proven by X-ray photoelectron spectroscopy and dynamic contact angle measurements. In addition, the stability of the activated 2C-PUR surface containing silanol groups was determined by measuring the contact angle as a function of time. Compared to the non-modified 2C-PUR systems the one with PDMS displayed a higher stability over a time period over 28 h. In a silanization process the coating was treated with (3-aminopropyl) trimethoxysilane and the enzyme was subsequently immobilized to the coating via the cross linker glutaraldehyde to receive new biomimetic catalytic/enzymatic functions. The chemical immobilization (chemisorption) of the enzyme to the surface showed statistically significant higher biological activity as compared to references samples without using a cross linker (physisorption). The presented technique offers the opportunity to design new and smart multifunctional surface coatings which employ biomimetic capabilities.

  11. Functionalization of PDMS modified and plasma activated two-component polyurethane coatings by surface attachment of enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Kreider, Alexej; Richter, Katharina; Sell, Stephan; Fenske, Mandus; Tornow, Christian; Stenzel, Volkmar [Fraunhofer Institute for Manufacturing Technology and Advanced Materials - IFAM, Wiener Strasse 12, 28359 Bremen (Germany); Grunwald, Ingo, E-mail: ingo.grunwald@ifam.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials - IFAM, Wiener Strasse 12, 28359 Bremen (Germany)

    2013-05-15

    This article describes a new strategy for coupling the enzyme horseradish peroxidase to a two-component polyurethane (2C-PUR) coating. A stable polymer conjugate was achieved by combining the enzyme and the 2C-PUR coating which was modified with poly(dimethylsiloxane) (PDMS), located at the surface. An atmospheric pressure plasma jet system was used to convert alkyl groups from the PDMS into polar silanol functionalities. This conversion was proven by X-ray photoelectron spectroscopy and dynamic contact angle measurements. In addition, the stability of the activated 2C-PUR surface containing silanol groups was determined by measuring the contact angle as a function of time. Compared to the non-modified 2C-PUR systems the one with PDMS displayed a higher stability over a time period over 28 h. In a silanization process the coating was treated with (3-aminopropyl) trimethoxysilane and the enzyme was subsequently immobilized to the coating via the cross linker glutaraldehyde to receive new biomimetic catalytic/enzymatic functions. The chemical immobilization (chemisorption) of the enzyme to the surface showed statistically significant higher biological activity as compared to references samples without using a cross linker (physisorption). The presented technique offers the opportunity to design new and smart multifunctional surface coatings which employ biomimetic capabilities.

  12. Effects of Estrogen Replacement Therapy on Lipid Peroxidation and Antioxidant Enzyme Activities of Ovariectomized and Ovariectomized-Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Aslı F. Ceylan-Işık

    2007-01-01

    Full Text Available Menopause and diabetes are conditions producing free radicals independently from each other. Estrogen replacement therapy which widely used in postmenopausal period has beneficial effects because of its antioxidant property. The study groups were as follows: ovariectomy (n=8, ovariectomy+17-östradiol (n=8, ovariectomy+diabetes (n=10 and ovariectomy+diabetes+17-östradiol (n=8. Diabetes was induced by streptozotocin (45 mg/kg i.p. and the treatment with 17-östradiol (0.1 mg/kg/day was started a week after ovariectomy. After–week long experimental period aortic and uterine tissues were collected from the animals and the malondialdehyde concentration, glutathione peroxidase and catalase activities were quantified. The treatment did not effect blood glucose concentrations, but increased plasma estradiol concentrations. Increased malondialdehyde concentrations were reduced by the treatment in aorta from diabetics and nondiabetics, but the treatment increased malondialdehyde concentrations in nondiabetic uterine while were reducing in diabetic uterine. The treatment also reduced the increased activities of catalase and glutathione peroxidase in aorta from diabetics and nondiabetics, on the other hand the treatment increased the activities of those enzymes in uterine from diabetics and nondiabetics. Our results suggested that estrogen acts as an antioxidant or prooxidant depending on the tissues.

  13. Differentiation between activity of digestive enzymes of Brachionus calyciflorus and extracellular enzymes of its epizooic bacteria

    Directory of Open Access Journals (Sweden)

    Wilko H. AHLRICHS

    2009-08-01

    Full Text Available The rotifer Brachionus calyciflorus was examined by scanning electron microscopy (SEM for surface-attached, i.e. epizootic, bacteria to ascertain their specific localization and thus find out if we could discern between rotifer and bacterial enzyme activity. The lorica of B. calyciflorus was colonized by one distinct type of bacteria, which originated from the algal culture used for rotifer feeding. The corona, posterior epidermis and foot of all inspected individuals were always without attached bacteria. The density of the attached bacteria was higher with the increasing age of B. calyciflorus: while young individuals were colonized by ~ tens of bacterial cells, older ones had on average hundreds to thousands of attached bacteria. We hypothesize that epizooic bacteria may produce the ectoenzymes phosphatases and β-N-acetylhexosaminidases on the lorica, but not on the corona of B. calyciflorus. Since enzyme activities of epizooic bacteria may influence the values and interpretation of bulk rotifer enzyme activities, we should take the bacterial contribution into account.

  14. [Interaction between CYP450 enzymes and metabolism of traditional Chinese medicine as well as enzyme activity assay].

    Science.gov (United States)

    Lu, Tu-lin; Su, Lian-lin; Ji, De; Gu, Wei; Mao, Chun-qin

    2015-09-01

    Drugs are exogenous compounds for human bodies, and will be metabolized by many enzymes after administration. CYP450 enzyme, as a major metabolic enzyme, is an important phase I drug metabolizing enzyme. In human bodies, about 75% of drug metabolism is conducted by CYP450 enzymes, and CYP450 enzymes is the key factor for drug interactions between traditional Chinese medicine( TCM) -TCM, TCM-medicine and other drug combination. In order to make clear the interaction between metabolic enzymes and TCM metabolism, we generally chose the enzymatic activity as an evaluation index. That is to say, the enhancement or reduction of CYP450 enzyme activity was used to infer the inducing or inhibitory effect of active ingredients and extracts of traditional Chinese medicine on enzymes. At present, the common method for measuring metabolic enzyme activity is Cocktail probe drugs, and it is the key to select the suitable probe substrates. This is of great significance for study drug's absorption, distribution, metabolism and excretion (ADME) process in organisms. The study focuses on the interaction between TCMs, active ingredients, herbal extracts, cocktail probe substrates as well as CYP450 enzymes, in order to guide future studies.

  15. Determination of metallothioneins based on the enhanced peroxidase-like activity of mercury-coated gold nanoparticles aggregated by metallothioneins

    International Nuclear Information System (INIS)

    Li, Xue-Jiao; Wang, Yong-Sheng; Yang, Sheng-Yuan; Tang, Xian; Zhou, Bin; Wang, Xiao-Feng; Zhu, Yu-Feng; Huang, Yan-Qin; He, Shun-Zhen; Liu, Lu

    2016-01-01

    We report on a photometric method for the determination of the metallothioneins (MTs). It is known that citrate capped gold nanoparticles (AuNPs) coated with traces of mercury possess peroxidase-like properties that can catalyze the oxidation of 2,2′-azino-bis(3-ethylbenzothiazoline- 6-sulfonate) (ABTS) to form a blue product in acetate buffer of pH 4.5. It is found that if the AuNPs are first aggregated by the cysteine-rich metallothioneins, the peroxidase-like properties of the resulting aggregates (AuNP-Hg-MTs) cause a largely accelerated oxidation of ABTS. The effect of adding MTs to such a solution is used to quantify the MTs by a kinetic assay. Changes in absorbance at 416 nm are linearly correlated to the concentration of MTs in the 4.3 to 49 nM range, and the detection limit is 1.3 nM. The method was successfully applied to the determination of MTs in (spiked) human urine. The strategy may pave the way for related detection platforms. (author)

  16. Production of manganese peroxidase by white rot fungi from potato ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-18

    Jan 18, 2010 ... production rate of the MnP using the potato-processing wastewater-based medium were higher (ca. 2.5- ... Ligninolytic enzymes, such as manganese peroxidase ... not currently reached industrial levels except for the laccase.

  17. Fluorogenic Substrates for Visualizing Acidic Organelle Enzyme Activities.

    Directory of Open Access Journals (Sweden)

    Fiona Karen Harlan

    Full Text Available Lysosomes are acidic cytoplasmic organelles that are present in all nucleated mammalian cells and are involved in a variety of cellular processes including repair of the plasma membrane, defense against pathogens, cholesterol homeostasis, bone remodeling, metabolism, apoptosis and cell signaling. Defects in lysosomal enzyme activity have been associated with a variety of neurological diseases including Parkinson's Disease, Lysosomal Storage Diseases, Alzheimer's disease and Huntington's disease. Fluorogenic lysosomal staining probes were synthesized for labeling lysosomes and other acidic organelles in a live-cell format and were shown to be capable of monitoring lysosomal metabolic activity. The new targeted substrates were prepared from fluorescent dyes having a low pKa value for optimum fluorescence at the lower physiological pH found in lysosomes. They were modified to contain targeting groups to direct their accumulation in lysosomes as well as enzyme-cleavable functions for monitoring specific enzyme activities using a live-cell staining format. Application to the staining of cells derived from blood and skin samples of patients with Metachromatic Leukodystrophy, Krabbe and Gaucher Diseases as well as healthy human fibroblast and leukocyte control cells exhibited localization to the lysosome when compared with known lysosomal stain LysoTracker® Red DND-99 as well as with anti-LAMP1 Antibody staining. When cell metabolism was inhibited with chloroquine, staining with an esterase substrate was reduced, demonstrating that the substrates can be used to measure cell metabolism. When applied to diseased cells, the intensity of staining was reflective of lysosomal enzyme levels found in diseased cells. Substrates specific to the enzyme deficiencies in Gaucher or Krabbe disease patient cell lines exhibited reduced staining compared to that in non-diseased cells. The new lysosome-targeted fluorogenic substrates should be useful for research

  18. Descriptive and predictive assessment of enzyme activity and enzyme related processes in biorefinery using IR spectroscopy and chemometrics

    DEFF Research Database (Denmark)

    Baum, Andreas

    the understanding of the structural properties of the extracted pectin. Secondly, enzyme kinetics of biomass converting enzymes was examined in terms of measuring enzyme activity by spectral evolution profiling utilizing FTIR. Chemometric multiway methods were used to analyze the tensor datasets enabling the second......-order calibration advantage (reference Theory of Analytical chemistry). As PAPER 3 illustrates the method is universally applicable without the need of any external standards and was exemplified by performing quantitative enzyme activity determinations for glucose oxidase, pectin lyase and a cellolytic enzyme blend...... (Celluclast 1.5L). In PAPER 4, the concept is extended to quantify enzyme activity of two simultaneously acting enzymes, namely pectin lyase and pectin methyl esterase. By doing so the multiway methods PARAFAC, TUCKER3 and NPLS were compared and evaluated towards accuracy and precision....

  19. Purification of peroxidase from Horseradish (Armoracia rusticana) roots.

    Science.gov (United States)

    Lavery, Christopher B; Macinnis, Morgan C; Macdonald, M Jason; Williams, Joanna Bassey; Spencer, Colin A; Burke, Alicia A; Irwin, David J G; D'Cunha, Godwin B

    2010-08-11

    Peroxidase (EC 1.11.1.7) from horseradish ( Armoracia rusticana ) roots was purified using a simple, rapid, three-step procedure: ultrasonication, ammonium sulfate salt precipitation, and hydrophobic interaction chromatography on phenyl Sepharose CL-4B. The preparation gave an overall yield of 71%, 291-fold purification, and a high specific activity of 772 U mg(-1) protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the purified enzyme was homogeneous and had a molecular weight of approximately 40 kDa. The isolated enzyme had an isoelectric point of 8.8 and a Reinheitszahl value of 3.39 and was stable when stored in the presence of glycerol at -20 degrees C, with >95% retention of original enzyme activity for at least 6 months. Maximal activity of purified horseradish peroxidase (HRP) was obtained under different optimized conditions: substrate (guaiacol and H(2)O(2)) concentrations (0.5 and 0.3 mM, respectively), type of buffer (50 mM phosphate buffer), pH (7.0), time (1.0 min), and temperature of incubation (30 degrees C). In addition, the effect of HRP and H(2)O(2) in a neutral-buffered aqueous solution for the oxidation of phenol and 2-chlorophenol substrates was also studied. Different conditions including concentrations of phenol/2-chlorophenol, H(2)O(2), and enzyme, time, pH, and temperature were standardized for the maximal activity of HRP with these substrates; under these optimal conditions 89.6 and 91.4% oxidations of phenol and 2-chlorophenol were obtained, respectively. The data generated from this work could have direct implications in studies on the commercial production of this biotechnologically important enzyme and its stability in different media.

  20. Dual-functional Pt-on-Pd supported on reduced graphene oxide hybrids: peroxidase-mimic activity and an enhanced electrocatalytic oxidation characteristic.

    Science.gov (United States)

    Zhang, Xiahong; Wu, Genghuang; Cai, Zhixiong; Chen, Xi

    2015-03-01

    In this study, a facile hydrothermal method was developed to synthesize Pt-on-Pd supported on reduced graphene oxide (Pt-on-Pd/RGO) hybrids. Because of the synergistic effect between Pt-on-Pd and RGO, the obtained Pt-on-Pd/RGO had superior peroxidase-mimic activities in H2O2 reduction and TMB oxidation. The reaction medium was optimized and a sensing approach for H2O2 was developed with a linear range from 0.98 to 130.7 μM of H2O2. In addition, the characteristic of electrocatalytic oxidation of methanol was investigated. The peak current density value, j(f), for the Pt-on-Pd/RGO hybrid (328 mA mg(Pt)(-1)) was about 1.85 fold higher than that of commercial Pt black (177 mA mg(Pt)(-1)) and, also, more durable electrocatalytic activity could be obtained. For the first time, the dual-functional Pt-on-Pd/RGO with peroxidase-mimic activity and an enhanced electrocatalytic oxidation characteristic was reported. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Enzyme activities by indicator of quality in organic soil

    Science.gov (United States)

    Raigon Jiménez, Mo; Fita, Ana Delores; Rodriguez Burruezo, Adrián

    2016-04-01

    The analytical determination of biochemical parameters, as soil enzyme activities and those related to the microbial biomass is growing importance by biological indicator in soil science studies. The metabolic activity in soil is responsible of important processes such as mineralization and humification of organic matter. These biological reactions will affect other key processes involved with elements like carbon, nitrogen and phosphorus , and all transformations related in soil microbial biomass. The determination of biochemical parameters is useful in studies carried out on organic soil where microbial processes that are key to their conservation can be analyzed through parameters of the metabolic activity of these soils. The main objective of this work is to apply analytical methodologies of enzyme activities in soil collections of different physicochemical characteristics. There have been selective sampling of natural soils, organic farming soils, conventional farming soils and urban soils. The soils have been properly identified conserved at 4 ° C until analysis. The enzyme activities determinations have been: catalase, urease, cellulase, dehydrogenase and alkaline phosphatase, which bring together a representative group of biological transformations that occur in the soil environment. The results indicate that for natural and agronomic soil collections, the values of the enzymatic activities are within the ranges established for forestry and agricultural soils. Organic soils are generally higher level of enzymatic, regardless activity of the enzyme involved. Soil near an urban area, levels of activities have been significantly reduced. The vegetation cover applied to organic soils, results in greater enzymatic activity. So the quality of these soils, defined as the ability to maintain their biological productivity is increased with the use of cover crops, whether or spontaneous species. The practice of cover based on legumes could be used as an ideal choice

  2. Enzyme activity in bioregulator-treated tomato (Solanum ...

    African Journals Online (AJOL)

    USER

    2010-05-31

    May 31, 2010 ... African Journal of Biotechnology Vol. 9(22), pp. 3264-3271, 31 ... In this work, spectrophotometric analysis ... most stable enzymes in vegetables and its thermal destruc-tion ... proteins, carbohydrates, lipids and allelochemicals (Hedin et al., 1995) ..... activities isolated from corn root plasma membrane. Plant.

  3. Phosphorus fractions, microbial biomass and enzyme activities in ...

    African Journals Online (AJOL)

    Potohar, northern Punjab, Pakistan in September, 2008 and analysed for P fractions and microbial parameters including microbial biomass C, microbial biomass N, microbial biomass P, and activities of dehydrogenase and alkaline phosphatase enzymes. The average size of different P fractions (% of total P) in the soils ...

  4. Tributyltin toxicity in abalone (Haliotis diversicolor supertexta) assessed by antioxidant enzyme activity, metabolic response, and histopathology.

    Science.gov (United States)

    Zhou, Jin; Zhu, Xiao-shan; Cai, Zhong-hua

    2010-11-15

    A toxicity test was performed to investigate the possible harmful effects of tributyltin (TBT) on abalone (Haliotis diversicolor supertexta). Animals were exposed to TBT in a range of environmentally relevant concentrations (2, 10 and 50 ng/L) for 30 days under laboratory conditions. TBT-free conditions were used as control treatments. The activity of antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD), and malondialdehyde (MDA), along with levels of haemolymph metabolites, and hepatopancreas histopathology were analyzed. The results showed that TBT decreased SOD activity, and increased POD level and MDA production in a dose-dependent way, indicating that oxidative injury was induced by TBT. Haemolymph metabolite measurements showed that TBT increased alanine and glutamate levels, and decreased glucose content, which suggested perturbation of energy metabolism. Elevated levels of acetate and pyruvate in the haemolymph indicated partial alteration of lipid metabolism. A decrease in lactate and an increase in succinate, an intermediate of the tricarboxylic acid (TCA) cycle, indicated disturbance of amino acid metabolism. Hepatopancreas tissues also exhibited inflammatory responses characterized by histopathological changes such as cell swelling, granular degeneration, and inflammation. Taken together, these results demonstrated that TBT was a potential toxin with a variety of deleterious effects on abalone. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Carotenoid-cleavage activities of crude enzymes from Pandanous amryllifolius.

    Science.gov (United States)

    Ningrum, Andriati; Schreiner, Matthias

    2014-11-01

    Carotenoid degradation products, known as norisoprenoids, are aroma-impact compounds in several plants. Pandan wangi is a common name of the shrub Pandanus amaryllifolius. The genus name 'Pandanus' is derived from the Indonesian name of the tree, pandan. In Indonesia, the leaves from the plant are used for several purposes, e.g., as natural colorants and flavor, and as traditional treatments. The aim of this study was to determine the cleavage of β-carotene and β-apo-8'-carotenal by carotenoid-cleavage enzymes isolated from pandan leaves, to investigate dependencies of the enzymatic activities on temperature and pH, to determine the enzymatic reaction products by using Headspace Solid Phase Microextraction Gas Chromatography/Mass Spectrophotometry (HS-SPME GC/MS), and to investigate the influence of heat treatment and addition of crude enzyme on formation of norisoprenoids. Crude enzymes from pandan leaves showed higher activity against β-carotene than β-apo-8'-carotenal. The optimum temperature of crude enzymes was 70°, while the optimum pH value was 6. We identified β-ionone as the major volatile reaction product from the incubations of two different carotenoid substrates, β-carotene and β-apo-8'-carotenal. Several treatments, e.g., heat treatment and addition of crude enzymes in pandan leaves contributed to the norisoprenoid content. Our findings revealed that the crude enzymes from pandan leaves with carotenoid-cleavage activity might provide a potential application, especially for biocatalysis, in natural-flavor industry. Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.

  6. Antioxidant Enzyme Activity, Iron Content and Lipid Oxidation of Raw and Cooked Meat of Korean Native Chickens and Other Poultry

    Directory of Open Access Journals (Sweden)

    Muhlisin

    2016-05-01

    Full Text Available This study was conducted to observe antioxidant enzyme activity, iron content and lipid oxidation of Korean native chickens and other poultry. The breast and thigh meat of three Korean native chicken breeds including Woorimatdak, Hyunin black and Yeonsan ogye, and three commercial poultry breeds including the broiler, White Leghorn and Pekin duck (Anasplatyrhyncos domesticus were studied. The analyses of the antioxidant enzymes activity, iron content and lipid oxidation were performed in raw and cooked samples. The activity of catalase (CAT in the thigh meat was higher than that of the breast meat of three Korean native chickens and the broiler, respectively. The activity of glutathione peroxidase (GPx in the uncooked thigh meat of three Korean native chickens was higher than that of the breasts. The breast meat of Woorimatdak and Pekin duck had higher superoxide dismutase (SOD activity than the others, while only the thigh meat of Pekin duck had the highest activity. Cooking inactivated CAT and decreased the activity of GPx and SOD. The thigh meat of Woorimatdak, White Leghorn, Yeonsan ogye and Hyunin black contained more total iron than the breast meat of those breeds. The heme-iron lost during cooking ranged from 3.2% to 14.8%. It is noted that the thigh meat had higher thiobarbituric acid reactive substances values than the breast in all chicken breeds. Though Woorimatdak showed higher antioxidant enzyme activity and lower released-iron percentage among Korean native chickens, no differences were found on lipid oxidation. We confirm that the dark meat of poultry exhibited higher antioxidant enzyme activity and contained more iron than the white meat.

  7. A metal-based inhibitor of NEDD8-activating enzyme.

    Directory of Open Access Journals (Sweden)

    Hai-Jing Zhong

    Full Text Available A cyclometallated rhodium(III complex [Rh(ppy(2(dppz](+ (1 (where ppy=2-phenylpyridine and dppz=dipyrido[3,2-a:2',3'-c]phenazine dipyridophenazine has been prepared and identified as an inhibitor of NEDD8-activating enzyme (NAE. The complex inhibited NAE activity in cell-free and cell-based assays, and suppressed the CRL-regulated substrate degradation and NF-κB activation in human cancer cells with potency comparable to known NAE inhibitor MLN4924. Molecular modeling analysis suggested that the overall binding mode of 1 within the binding pocket of the APPBP1/UBA3 heterodimer resembled that for MLN4924. Complex 1 is the first metal complex reported to suppress the NEDDylation pathway via inhibition of the NEDD8-activating enzyme.

  8. Characterization of Carbohydrate Active Enzymes Involved in Arabinogalactan Protein Metabolism

    DEFF Research Database (Denmark)

    Knoch, Eva

    and tissues, their functions and synthesis are still poorly understood. The aim of the research presented in the thesis was to characterize carbohydrate active enzymes involved in AGP biosynthesis and modification to gain insights into the biosynthesis of the glycoproteins in plants. Candidate...... glycosyltransferases and glycoside hydrolases were selected based on co-expression profiles from a transcriptomics analysis. Reverse genetics approach on a novel glucuronosyltransferase involved in AGP biosynthesis has revealed that the enzyme activity is required for normal cell elongation in etiolated seedlings....... The enzymatic activity of a hydrolase from GH family 17 was investigated, without successful determination of the activity. Members of hydrolase family 43 appeared to be localized in the Golgi-apparatus, which is also the compartment for glycan biosynthesis. The localization of these glycoside hydrolases...

  9. Influence of salicylic and succinic acids on antioxidant enzymes activity, heat resistance and productivity of Panicum miliaceum L.

    Directory of Open Access Journals (Sweden)

    Miroshnichenko N.N.

    2011-05-01

    Full Text Available The influence of treatment of millet (Panicum miliaceum L. seeds with the solutions of salicylic and succinic acids on the heat resistance of plantlets and activity of antioxidant enzymes – superoxide dismutase (SOD, catalase and peroxidase – in them have been investigated. In the micro-field experiment the influence of these acids on the millet yield was estimated. The action of salicylic (10 μM and succinic (1 mM acids caused the increase of plantlets resistance to the damaging heating that expressed in the rise of relative quantity of survived plantlets in 5 days after heating at the temperature of 47°С and in the reduced content of lipid peroxidation product malonic dialdehyde during the poststress period. The increase of activity of SOD, catalase and peroxidase took place in millet plantlets under the influence of salicylic and succinic acids. The increase of productivity of millet grain under the action of salicylic and succinic acids on 13,3-52,0 and 6,4-38,8% respectively depending on weather conditions in the field experiments was noted.

  10. Optimization of lignin peroxidase, manganese peroxidase, and Lac production from Ganoderma lucidum under solid state fermentation of pineapple leaf

    OpenAIRE

    Sudha Hariharan; Padma Nambisan

    2013-01-01

    This study was undertaken to isolate ligninase-producing white-rot fungi for use in the extraction of fibre from pineapple leaf agriwaste. Fifteen fungal strains were isolated from dead tree trunks and leaf litter. Ligninolytic enzymes (lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac)), were produced by solid-state fermentation (SSF) using pineapple leaves as the substrate. Of the isolated strains, the one showing maximum production of ligninolytic enzymes was identified...

  11. Co-ordinate activation of lipogenic enzymes in hepatocellular carcinoma.

    Science.gov (United States)

    Yahagi, Naoya; Shimano, Hitoshi; Hasegawa, Kiyoshi; Ohashi, Kenichi; Matsuzaka, Takashi; Najima, Yuho; Sekiya, Motohiro; Tomita, Sachiko; Okazaki, Hiroaki; Tamura, Yoshiaki; Iizuka, Yoko; Ohashi, Ken; Nagai, Ryozo; Ishibashi, Shun; Kadowaki, Takashi; Makuuchi, Masatoshi; Ohnishi, Shin; Osuga, Jun-ichi; Yamada, Nobuhiro

    2005-06-01

    Hepatocellular carcinoma is a very common neoplastic disease in countries where hepatitis viruses B and/or C are prevalent. Small hepatocellular carcinoma lesions detected by ultrasonography at an early stage are often hyperechoic because they are composed of well-differentiated cancer cells that are rich in triglyceride droplets. The triglyceride content of hepatocytes depends in part on the rate of lipogenesis. Key lipogenic enzymes, such as fatty acid synthase, are co-ordinately regulated at the transcriptional level. We therefore examined the mRNA expression of lipogenic enzymes in human hepatocellular carcinoma samples from 10 patients who had undergone surgical resection. All of the samples exhibited marked elevation of expression of mRNA for lipogenic enzymes, such as fatty acid synthase, acetyl-CoA carboxylase and ATP citrate lyase, compared with surrounding non-cancerous liver tissue. In contrast, the changes in mRNA expression of SREBP-1, a transcription factor that regulates a battery of lipogenic enzymes, did not show a consistent trend. In some cases where SREBP-1 was elevated, the main contributing isoform was SREBP-1c rather than SREBP-1a. Thus, lipogenic enzymes are markedly induced in hepatocellular carcinomas, and in some cases SREBP-1c is involved in this activation.

  12. Light-regulation of enzyme activity in anacystis nidulans (Richt.).

    Science.gov (United States)

    Duggan, J X; Anderson, L E

    1975-01-01

    The effect of light on the levels of activity of six enzymes which are light-modulated in higher plants was examined in the photosynthetic procaryot Anacystis nidulans. Ribulose-5-phosphate kinase (EC 2.7.1.19) was found to be light-activated in vivo and dithiothreitol-activated in vitro while glucose-6-phosphate dehydrogenase (EC 1.1.1.49) was light-inactivated and dithiothreitol-inactivated. The enzymes fructose-1,6-diphosphate phosphatase (EC 3.1.3.11), sedoheptulose-1,7-diphosphate phosphatase, NAD- and NADP-linked glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12; EC 1.2.1.13) were not affected by light treatment of the intact algae, but sedoheptulose-diphosphate phosphatase and the glyceraldehyde-3-phosphate dehydrogenases were dithiothreitol-activated in crude extracts. Light apparently controls the activity of the reductive and oxidative pentose phosphate pathway in this photosynthetic procaryot as in higher plants, through a process which probably involves reductive modulation of enzyme activity.

  13. Thiol peroxidases mediate specific genome-wide regulation of gene expression in response to hydrogen peroxide

    Science.gov (United States)

    Fomenko, Dmitri E.; Koc, Ahmet; Agisheva, Natalia; Jacobsen, Michael; Kaya, Alaattin; Malinouski, Mikalai; Rutherford, Julian C.; Siu, Kam-Leung; Jin, Dong-Yan; Winge, Dennis R.; Gladyshev, Vadim N.

    2011-01-01

    Hydrogen peroxide is thought to regulate cellular processes by direct oxidation of numerous cellular proteins, whereas antioxidants, most notably thiol peroxidases, are thought to reduce peroxides and inhibit H2O2 response. However, thiol peroxidases have also been implicated in activation of transcription factors and signaling. It remains unclear if these enzymes stimulate or inhibit redox regulation and whether this regulation is widespread or limited to a few cellular components. Herein, we found that Saccharomyces cerevisiae cells lacking all eight thiol peroxidases were viable and withstood redox stresses. They transcriptionally responded to various redox treatments, but were unable to activate and repress gene expression in response to H2O2. Further studies involving redox transcription factors suggested that thiol peroxidases are major regulators of global gene expression in response to H2O2. The data suggest that thiol peroxidases sense and transfer oxidative signals to the signaling proteins and regulate transcription, whereas a direct interaction between H2O2 and other cellular proteins plays a secondary role. PMID:21282621

  14. Micropollutant degradation via extracted native enzymes from activated sludge.

    Science.gov (United States)

    Krah, Daniel; Ghattas, Ann-Kathrin; Wick, Arne; Bröder, Kathrin; Ternes, Thomas A

    2016-05-15

    A procedure was developed to assess the biodegradation of micropollutants in cell-free lysates produced from activated sludge of a municipal wastewater treatment plant (WWTP). This proof-of-principle provides the basis for further investigations of micropollutant biodegradation via native enzymes in a solution of reduced complexity, facilitating downstream protein analysis. Differently produced lysates, containing a variety of native enzymes, showed significant enzymatic activities of acid phosphatase, β-galactosidase and β-glucuronidase in conventional colorimetric enzyme assays, whereas heat-deactivated controls did not. To determine the enzymatic activity towards micropollutants, 20 compounds were spiked to the cell-free lysates under aerobic conditions and were monitored via LC-ESI-MS/MS. The micropollutants were selected to span a wide range of different biodegradabilities in conventional activated sludge treatment via distinct primary degradation reactions. Of the 20 spiked micropollutants, 18 could be degraded by intact sludge under assay conditions, while six showed reproducible degradation in the lysates compared to the heat-deactivated negative controls: acetaminophen, N-acetyl-sulfamethoxazole (acetyl-SMX), atenolol, bezafibrate, erythromycin and 10,11-dihydro-10-hydroxycarbamazepine (10-OH-CBZ). The primary biotransformation of the first four compounds can be attributed to amide hydrolysis. However, the observed biotransformations in the lysates were differently influenced by experimental parameters such as sludge pre-treatment and the addition of ammonium sulfate or peptidase inhibitors, suggesting that different hydrolase enzymes were involved in the primary degradation, among them possibly peptidases. Furthermore, the transformation of 10-OH-CBZ to 9-CA-ADIN was caused by a biologically-mediated oxidation, which indicates that in addition to hydrolases further enzyme classes (probably oxidoreductases) are present in the native lysates. Although the

  15. ATPase Activity Measurements by an Enzyme-Coupled Spectrophotometric Assay.

    Science.gov (United States)

    Sehgal, Pankaj; Olesen, Claus; Møller, Jesper V

    2016-01-01

    Enzymatic coupled assays are usually based on the spectrophotometric registration of changes in NADH/NAD(+) or NADPH/NADP(+) absorption at 340 nm accompanying the oxidation/reduction of reactants that by dehydrogenases and other helper enzymes are linked to the activity of the enzymatic reaction under study. The present NADH-ATP-coupled assay for ATPase activity is a seemingly somewhat complicated procedure, but in practice adaptation to performance is easily acquired. It is a more safe and elegant method than colorimetric methods, but not suitable for handling large number of samples, and also presupposes that the activity of the helper enzymes is not severely affected by the chemical environment of the sample in which it is tested.

  16. Relationship between glutation peroxidase (GSH-PX) activity and the uptake of 75-Se by erytrocytes for practical assesment of selenium status in dairy cows

    International Nuclear Information System (INIS)

    Danius, J.

    1988-01-01

    An experiment to study the relationship between glutation peroxidase (GSH-Px) activity and the uptake of 75-Se by erytrocytes was conducted for practical assesment of selenium status in Holstein-Friesian (HF) dairy cows. The blood used in the experiment was stored in refrigerator for 7 and 10 days. Radioselenium with a specific activity at about 0.84 mCi/m was used. A high negative correlatin (r = -0.86 and r = -0.98) was found between red blood cell GSH-Px activity and red blood cell uptake of 75-Se. Results indicated that red blood cell uptake of 75-Se can be used for determination of Se status in dairy cattle, although some factors which might affect red blood cell uptake of 75-Se should be calculated first. (author). 21 refs, 2 figs

  17. Ratio Imaging of Enzyme Activity Using Dual Wavelength Optical Reporters

    Directory of Open Access Journals (Sweden)

    Moritz F. Kircher

    2002-04-01

    Full Text Available The design of near-infrared fluorescent (NIRF probes that are activated by specific proteases has, for the first time, allowed enzyme activity to be imaged in vivo. In the current study, we report on a method of imaging enzyme activity using two fluorescent probes that, together, provide improved quantitation of enzymatic activity. The method employs two chemically similar probes that differ in their degradability by cathepsin B. One probe consists of the NIRF dye Cy5.5 attached to a particulate carrier, a crosslinked iron oxide nanoparticle (CLIO, through cathepsin B cleavable l-arginyl peptides. A second probe consists of Cy3.5 attached to a CLIO through proteolytically resistant d-arginyl peptides. Using mixtures of the two probes, we have shown that the ratio of Cy5.5 to Cy3.5 fluorescence can be used to determine levels of cathepsin B in the environment of nanoparticles with macrophages in suspension. After intravenous injection, tissue fluorescence from the nondegradable Cy3.5–d-arginyl probe reflected nanoparticle accumulation, while fluorescence of the Cy5.5–l-arginyl probe was dependent on both accumulation and activation by cathepsin B. Dual wavelength ratio imaging can be used for the quantitative imaging of a variety of enzymes in clinically important settings, while the magnetic properties of the probes allow their detection by MR imaging.

  18. Cigarette smoke–induced induction of antioxidant enzyme activities in airway leukocytes is absent in active smokers with COPD

    Science.gov (United States)

    Dove, Rosamund E.; Leong-Smith, Pheneatia; Roos-Engstrand, Ester; Pourazar, Jamshid; Shah, Mittal; Behndig, Annelie F.; Mudway, Ian S.; Blomberg, Anders

    2015-01-01

    Background Oxidative injury to the airway has been proposed as an important underlying mechanism in the pathogenesis of chronic obstructive pulmonary disease (COPD). As the extent of oxidant-mediated damage is dependent on the endogenous antioxidant defences within the airways, we examined whether COPD was associated with deficiencies in the antioxidant network within the respiratory tract lining fluids (RTLFs) and resident airway leukocytes. We hypothesised that COPD would be associated with both basal depression of antioxidant defences and impaired adaptive antioxidant responses to cigarette smoke. Methods Low molecular weight and enzymatic antioxidants together with metal-handling proteins were quantified in bronchoalveolar lavage fluid and airway leukocytes, derived from current (n=9) and ex-smoking COPD patients (n=15), as well as from smokers with normal lung function (n=16) and healthy never smokers (n=13). Results Current cigarette smoking was associated with an increase in ascorbate and glutathione within peripheral RTLFs in both smokers with normal lung function compared with healthy never smokers and in COPD smokers compared with COPD ex-smokers. In contrast, intra-cellular antioxidant enzyme activities (glutathione peroxidase, glutathione reductase, and catalase) were only up-regulated in smokers with normal lung function compared with healthy never smokers and not in actively smoking COPD patients relative to COPD ex-smokers. Conclusions We found no evidence of impaired basal antioxidant defences, within either the RTLFs or airway leukocytes in stable ex-smoking COPD patients compared with healthy never smoking controls. Current cigarette smoking induced an up-regulation of low molecular weight antioxidants in the RTLFs of both control subjects with normal lung function and patients with COPD. Importantly, the present data demonstrated a cigarette smoke–induced increase in intra-cellular antioxidant enzyme activities only within the smokers with

  19. Arabidopsis thaliana peroxidase N

    DEFF Research Database (Denmark)

    Mirza, Osman Asghar; Henriksen, A; Ostergaard, L

    2000-01-01

    The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C...... (HRP C). HRP C is 54% identical to ATP N in sequence. When the structures of four class III plant peroxidases are superimposed, the regions with structural differences are non-randomly distributed; all are located in one half of the molecule. The architecture of the haem pocket of ATP N is very similar...... to that of HRP C, in agreement with the low small-molecule substrate specificity of all class III peroxidases. The structure of ATP N suggests that the pH dependence of the substrate turnover will differ from that of HRP C owing to differences in polarity of the residues in the substrate-access channel. Since...

  20. Effect of Barley and Enzyme on Performance, Carcass, Enzyme Activity and Digestion Parameters of Broilers

    Directory of Open Access Journals (Sweden)

    majid kalantar

    2016-04-01

    Full Text Available Introduction Corn has been recently used for producing ethanol fuel in the major corn-producing countries such as the US and Brazil. Recent diversion of corn for biofuel production along with the increased world's demand for this feedstuff has resulted in unprecedented rise in feed cost for poultry worldwide. Alternative grains such as wheat and barley can be successfully replaced for corn in poultry diets. These cereal grains can locally grow in many parts of the world as they have remarkably lower water requirement than corn. Wheat and barley are generally used as major sources of energy in poultry diets. Though the major components of these grains are starch and proteins, they have considerable content of non-starch polysaccharides (NSPs, derived from the cell walls (Olukosi et al. 2007; Mirzaie et al. 2012. NSPs are generally considered as anti-nutritional factors (Jamroz et al. 2002. The content and structure of NSP polymers vary between different grains, which consequently affect their nutritive value (Olukosi et al. 2007.Wheat and barley are generally used as major sources of energy in poultry diets. The major components of these grains are starch and proteins, they have considerable content of non-starch polysaccharides (NSPs, derived from the cell walls. NSPs are generally considered as anti-nutritional factors. The content and structure of NSP polymers vary between different grains, which consequently affect their nutritive value. The major part of NSPs in barley comprises polymers of (1→3 (1→4-β- glucans which could impede growth factors and consequently carcass quality through lowering the rate and amount of available nutrients in the mucosal surface of the intestinal. Materials and Methods This experiment was conducted to evaluate the effect of corn and barley based diets supplemented with multi-enzyme on growth, carcass, pancreas enzyme activity and physiological characteristics of broilers. A total number of 375 one day old

  1. Genetic variability in chronic irradiated plant populations - Polymorphism and activity of antioxidant enzymes in chronic irradiated plant populations

    Energy Technology Data Exchange (ETDEWEB)

    Volkova, Polina Y.; Geras' kin, Stanislav A. [Russian Institute of Agricultural Radiology and Agroecology, 249030, Obninsk, Kievskoe shosse 109 km (Russian Federation)

    2014-07-01

    Introduction: The gene pool of natural population is constantly changing in order to provide the greatest fitness at this time. Ability of population to adapt to changing environmental conditions depends on genetic polymorphism of traits which are operates by selection. Chronic stress exposure can change amount or structure intra-population variability. Therefore, it is necessary to analyze the relationships between genetic polymorphism and stress factors, such as radiation exposure. This studies my assist in the development of new bio-indication methods. Materials and methods: Studying sites: Bryansk region is the most contaminated region of Russia as a result of Chernobyl accident. The initial activity by {sup 137}Cs on this territory reached 1 MBq/m{sup 2} above surface. Our study conducted in several districts of Bryansk region, which are characterized the most dose rate. Experimental sites similar to climate characteristics, stand of trees is homogeneous, pine trees take up a significant part of phytocenosis. Heavy metals content in soils and cones be within background. Dose rates vary from 0.14 to 130 mGy/year. Object: Pinus sylvestris L.,the dominant tree species in North European and Asian boreal forests. Scots pine has a long maturation period (18-20 month), which means that significant DNA damage may accumulate in the undifferentiated stem cells, even at low doses (or dose rates) during exposure to low concentrations of contaminants Isozyme analysis: We evaluated isozyme polymorphism of three antioxidant enzymes: superoxide dismutase, glutatione reductase and glutatione peroxidase. Analysis of enzymes activities: We chose key enzymes of antioxidant system for this experiment: superoxide dismutase, catalase and peroxidase. Results and conclusions: We estimated frequency of each allele in reference and experimental populations. based It was showed that frequency of rare alleles increase in chronic irradiated populations, i.e. increase the sampling variance

  2. Chitosan controls postharvest anthracnose in bell pepper by activating defense-related enzymes.

    Science.gov (United States)

    Edirisinghe, Madushani; Ali, Asgar; Maqbool, Mehdi; Alderson, Peter G

    2014-12-01

    Anthracnose, a postharvest disease caused by the fungus Colletotrichum capsici is the most devastating disease of bell pepper that causes great economic losses especially in tropical climates. Therefore, the objective of this study was to evaluate the antifungal properties of chitosan (low molecular weight from crab shell, Mw: 50 kDa and 75-85 % deacetylated) against anthracnose by inducing defense-related enzymes. The concentrations of 0, 0.5, 1.0, 1.5 and 2.0 % chitosan were used to control the fungus in vitro and postharvest. There was a reduction in C. capsici mycelial growth and the highest chitosan concentration (2.0 %) reduced the growth by 70 % after 7 days incubation. In germination test, the concentration of 1.5 and 2.0 % chitosan reduced spore germination in C. capsici between 80 % and 84 %, respectively. In postharvest trial the concentration of 1.5 % decreased the anthracnose severity in pepper fruit by approximately 76 % after 28 days of storage (10 ± 1 °C; 80 % RH). For enzymatic activities, the concentration of 1.5 and 2.0 % chitosan increased the polyphenol oxidase (PPO), peroxidase (POD) and total phenolics in inoculated bell pepper during storage. Based on these results, the chitosan presents antifungal properties against C. capsici, as well as potential to induce resistance on bell pepper.

  3. Rhizobacteria induces resistance against Fusarium wilt of tomato by increasing the activity of defense enzymes

    Directory of Open Access Journals (Sweden)

    Hélvio Gledson Maciel Ferraz

    2014-09-01

    Full Text Available Fusarium wilt, caused by Fusarium oxysporum f.sp. lycopersici (Fol, is one of the most important diseases that affect tomato yield worldwide. This study investigated the potential of three antagonists, Streptomyces setonii (UFV 618, Bacillus cereus (UFV 592 and Serratia marcescens (UFV 252, and as positive control the hormone jasmonic acid (JA, to reduce Fusarium wilt symptoms and to potentiate the defense enzymes in the stem tissues of tomato plants infected by Fol. The seeds were microbiolized with each antagonist, and the soil was also drenched with them. The plants were sprayed with JA 48 h before Fol inoculation. The area under the Fusarium wilt index progress curve was reduced by 54, 48, 47 and 45% for the UFV 618, JA, UFV 592 and UFV 252 treatments, respectively. The three antagonists, and even the JA spray, efficiently reduced the Fusarium wilt symptoms on the tomato plant stems, which can be explained by the lower malondialdehyde concentration (an indication of oxidative damage to lipids in the plasma membranes and the greater activities of peroxidases, polyphenoloxidases, glucanases, chitinases, phenylalanine ammonia-lyases and lipoxygenases, which are commonly involved in host resistance against fungal diseases. These results present a novel alternative that can be used in the integrated management of Fusarium wilt on tomatoes.

  4. Catalytic and peroxidase-like activity of carbon based-AuPd bimetallic nanocomposite produced using carbon dots as the reductant

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liuqing [Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081 (China); Liu, Xiaoying [College of Science, Science and Technological Innovation Platform, Hunan Agricultural University, Hunan, Changsha 410128 (China); Lu, Qiujun; Huang, Na [Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081 (China); Liu, Meiling, E-mail: liumeilingww@126.com [Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081 (China); Zhang, Youyu; Yao, Shouzhuo [Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education, China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081 (China)

    2016-08-03

    In this report, carbon-based AuPd bimetallic nanocomposite (AuPd/C NC) was synthesized using carbon dots (C-dots) as the reducing agent and stabilizer by a simple green sequential reduction strategy, without adding other agents. The as synthesized AuPd/C NC showed good catalytic activity and peroxidase-like property. The structure and morphology of these nanoparticles were clearly characterized by UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The AuPd/C NC catalyst exhibits noticeably higher catalytic activity than Pd and Au nanoparticles in catalysis reduction of 4-nitrophenol (4-NP). Moreover, based on the high peroxidase-like property of AuPd/C NC, a new colorimetric detection method for hydrogen peroxide (H{sub 2}O{sub 2}) has been designed using 3,3′,5,5′-tetramethyl-benzidine (TMB) as the substrate, which provides a simple and sensitive means to detect H{sub 2}O{sub 2} in wide linear range of 5 μM–500 μM and 500 μM–4 mM with low detection limit of 1.6 μM (S/N = 3). Therefore, the facile synthesis strategy for bimetallic nanoparticles by the mild reductant of carbon dot will provide some new thoughts for preparing of carbon-based metal nanomaterials and expand their application in catalysis and analytical chemistry areas. - Highlights: • Carbon-based AuPd bimetallic nanocomposite was synthesized using carbon dots. • The green sequential reduction strategy synthesis method is simple, green, convenient and effective. • The as synthesized AuPd/C NC showed good catalytic activity and peroxidase-like activity. • The AuPd/C NC exhibits noticeably higher catalytic activity in reduction of 4-nitrophenol. • A new colorimetric detection method for hydrogen peroxide based on AuPd/C NC was proposed.

  5. In silico molecular modeling and docking studies on the leishmanial tryparedoxin peroxidase

    Directory of Open Access Journals (Sweden)

    Ozal Mutlu

    2014-04-01

    Full Text Available Leishmaniasis is one of the most common form of neglected parasitic disease that affects about 350 million people worldwide. Leishmanias have a trypanothione mediated hydroperoxide metabolism to eliminate endogenous or exogenous oxidative agents. Both of 2-Cys peroxiredoxin (Prx and glutathione peroxidase type tryparedoxin peroxidase (Px are the terminal enzymes in the trypanothione dependent detoxification system. Therefore absence of trypanothione redox system in mammals and the sensitivity of trypanosomatids against oxidative stress, enzymes of this pathway are drug targets candidates. In this study, 3D structure of tryparedoxin peroxidase (2-Cys peroxiredoxin type from Leishmania donovani (LdTXNPx was described by homology modeling method based on the template of tryparedoxin peroxidase from Crithidia fasciculata and selected compounds were docked to the active site pocket. The quality of the 3D structure of the model was confirmed by various web based validation programs. When compared secondary and tertiary structure of the model, it showed a typical thioredoxin fold containing a central beta-sheet and three alpha-helices. Docking study showed that the selected compound 2 (CID 16073813 interacted with the active site amino acids and binding energy was -118.675 kcal/mol.

  6. Extracellular enzyme activity in a willow sewage treatment system.

    Science.gov (United States)

    Brzezinska, Maria Swiontek; Lalke-Porczyk, Elżbieta; Kalwasińska, Agnieszka

    2012-12-01

    This paper presents the results of studies on the activity of extra-cellular enzymes in soil-willow vegetation filter soil which is used in the post-treatment of household sewage in an onsite wastewater treatment system located in central Poland. Wastewater is discharged from the detached house by gravity into the onsite wastewater treatment system. It flows through a connecting pipe into a single-chamber septic tank and is directed by the connecting pipe to a control well to be further channelled in the soil-willow filter by means of a subsurface leaching system. Soil samples for the studies were collected from two depths of 5 cm and 1 m from three plots: close to the wastewater inflow, at mid-length of the plot and close to its terminal part. Soil samples were collected from May to October 2009. The activity of the extra-cellular enzymes was assayed by the fluorometric method using 4-methylumbelliferyl and 7-amido-4-methylcoumarin substrate. The ranking of potential activity of the assayed enzymes was the same at 5 cm and 1 m soil depths, i.e. esterase > phosphmomoesterase > leucine-aminopeptidase > β-glucosidase > α-glucosidase. The highest values of enzymatic activity were recorded in the surface layer of the soil at the wastewater inflow and decreased with increasing distance from that point.

  7. Thioredoxin 1 in Prostate Tissue Is Associated with Gleason Score, Erythrocyte Antioxidant Enzyme Activity, and Dietary Antioxidants

    Directory of Open Access Journals (Sweden)

    Terrence M. Vance

    2015-01-01

    Full Text Available Background. Prostate cancer is the most common noncutaneous cancer and second leading cause of cancer-related mortality in men in the US. Growing evidence suggests that oxidative stress is involved in prostate cancer. Methods. In this study, thioredoxin 1 (Trx 1, an enzyme and subcellular indicator of redox status, was measured in prostate biopsy tissue from 55 men from the North Carolina-Louisiana Prostate Cancer Project. A pathologist blindly scored levels of Trx 1. The association between Trx 1 and the Gleason score, erythrocyte antioxidant enzyme activity, and dietary antioxidant intake was determined using Fisher’s exact test. Results. Trx 1 levels in benign prostate tissue in men with incident prostate cancer were positively associated with the Gleason score (P=0.01 and inversely associated with dietary antioxidant intake (P=0.03. In prostate cancer tissue, Trx 1 levels were associated with erythrocyte glutathione peroxidase activity (P=0.01. No association was found for other erythrocyte enzymes. Greater Gleason score of malignant tissue corresponds to a greater difference in Trx 1 levels between malignant and benign tissue (P=0.04. Conclusion. These results suggest that the redox status of prostate tissue is associated with prostate cancer grade and both endogenous and exogenous antioxidants.

  8. Horseradish peroxidase embedded in polyacrylamide nanoparticles enables optical detection of reactive oxygen species

    DEFF Research Database (Denmark)

    Poulsen, A.K.; Scharff-Poulsen, Anne Marie; Olsen, L.F.

    2007-01-01

    We have synthesized and characterized new nanometer-sized polyacrylamide particles containing horseradish peroxidase and fluorescent dyes. Proteins and dyes are encapsulated by radical polymerization in inverse microemulsion. The activity of the encapsulated enzyme has been examined and it mainta......We have synthesized and characterized new nanometer-sized polyacrylamide particles containing horseradish peroxidase and fluorescent dyes. Proteins and dyes are encapsulated by radical polymerization in inverse microemulsion. The activity of the encapsulated enzyme has been examined...... for quantification of hydrogen peroxide and other reactive oxygen species in microenvironments, and we propose that the particles may find use as nanosensors for use in, e.g., living cells. (C) 2007 Elsevier Inc. All rights reserved....

  9. Effects of Droplet-Vitrification Cryopreservation Based on Physiological and Antioxidant Enzyme Activities of Brassidium Shooting Star Orchid

    Directory of Open Access Journals (Sweden)

    Safrina Rahmah

    2015-01-01

    Full Text Available Protocorm-like bodies (PLBs of Brassidium Shooting Star orchid were successfully cryopreserved using droplet-vitrification method. Vitrification based cryopreservation protocol is comprised of preculture, osmoprotection, cryoprotection, cooling, rewarming, and growth recovery and each and every step contributes to the achievement of successful cryopreservation. In order to reveal the lethal and nonlethal damage produced by cryopreservation, histological observation, scanning electron microscopy (SEM, and biochemical analysis were carried out in both cryopreserved and noncryopreserved PLBs of Brassidium Shooting Star orchid comparing with the control PLBs stock culture. Histological and scanning electron microscopy analyses displayed structural changes in cryopreserved PLBs due to the impact of cryoinjury during exposure to liquid nitrogen. Total soluble protein significantly increased throughout the dehydration process and the highest value was achieved when PLBs were stored in liquid nitrogen. Ascorbate peroxidase (APX and catalase (CAT showed the highest enzyme activities in both dehydration and cryostorage treatments indicating that stress level of PLBs was high during these stages.

  10. Prostaglandin levels and lysosomal enzyme activities in irradiated rats

    International Nuclear Information System (INIS)

    Trocha, P.J.; Catravas, G.N.

    1980-01-01

    Whole-body irradiation of rats results in the release of hydrolases from lysosomes, an increase in lysosomal enzyme activities, and changes in the prostaglandin levels in spleen and liver tissues. A transient increase in the concentration of prostaglandins E and F and leakage of lysosomal hydrolases occurred in both spleen and liver tissues 3-6 hours after the animals were irradiated. Maximal values for hydrolase activities, prostaglandin E and F content, and release of lysosomal enzymes were found 4 days postirradiation in rat spleens whereas in the liver only slight increases were observed at this time period for prostaglandin F levels. On day 7 there was a final rise in the spleen's prostaglandin E and F concentrations and leakage of hydrolases from the lysosomes before returning to near normal values on day 11. The prostaglandin F concentration in liver was also slightly elevated on the 7th day after irradiation and then decreased to control levels. (author)

  11. DNA-enhanced peroxidase-like activity of layered double hydroxide nanosheets and applications in H2O2 and glucose sensing.

    Science.gov (United States)

    Chen, Lijian; Sun, Kaifang; Li, Peipei; Fan, Xianzhong; Sun, Jianchao; Ai, Shiyun

    2013-11-21

    LDH nanosheets were obtained via continuous impaction and exfoliation by herring sperm DNA molecules using a constant vibration method. DNA-LDH nanohybrids were composed by electrostatic forces and they exhibited DNA-enhanced peroxidase-like activity. The morphology and structure of DNA-LDH nanohybrids were analyzed by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), X-ray diffraction (XRD), and atomic force microscopy (AFM) characterization. On the basis of the high catalytic activity of DNA/CuAl-LDH nanosheets, a rapid, sensitive, and convenient approach was developed for colorimetric detection of H2O2 and blood glucose. This method can be potentially applied in medical diagnostics and biotechnology fields.

  12. In vivo enzyme activity in inborn errors of metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, G.N.; Walter, J.H.; Leonard, J.V.; Halliday, D. (Clinical Research Centre, Harrow (England))

    1990-08-01

    Low-dose continuous infusions of (2H5)phenylalanine, (1-13C)propionate, and (1-13C)leucine were used to quantitate phenylalanine hydroxylation in phenylketonuria (PKU, four subjects), propionate oxidation in methylmalonic acidaemia (MMA, four subjects), and propionic acidaemia (PA, four subjects) and leucine oxidation in maple syrup urine disease (MSUD, four subjects). In vivo enzyme activity in PKU, MMA, and PA subjects was similar to or in excess of that in adult controls (range of phenylalanine hydroxylation in PKU, 3.7 to 6.5 mumol/kg/h, control 3.2 to 7.9, n = 7; propionate oxidation in MMA, 15.2 to 64.8 mumol/kg/h, and in PA, 11.1 to 36.0, control 5.1 to 19.0, n = 5). By contrast, in vivo leucine oxidation was undetectable in three of the four MSUD subjects (less than 0.5 mumol/kg/h) and negligible in the remaining subject (2 mumol/kg/h, control 10.4 to 15.7, n = 6). These results suggest that significant substrate removal can be achieved in some inborn metabolic errors either through stimulation of residual enzyme activity in defective enzyme systems or by activation of alternate metabolic pathways. Both possibilities almost certainly depend on gross elevation of substrate concentrations. By contrast, only minimal in vivo oxidation of leucine appears possible in MSUD.

  13. In vivo enzyme activity in inborn errors of metabolism

    International Nuclear Information System (INIS)

    Thompson, G.N.; Walter, J.H.; Leonard, J.V.; Halliday, D.

    1990-01-01

    Low-dose continuous infusions of [2H5]phenylalanine, [1-13C]propionate, and [1-13C]leucine were used to quantitate phenylalanine hydroxylation in phenylketonuria (PKU, four subjects), propionate oxidation in methylmalonic acidaemia (MMA, four subjects), and propionic acidaemia (PA, four subjects) and leucine oxidation in maple syrup urine disease (MSUD, four subjects). In vivo enzyme activity in PKU, MMA, and PA subjects was similar to or in excess of that in adult controls (range of phenylalanine hydroxylation in PKU, 3.7 to 6.5 mumol/kg/h, control 3.2 to 7.9, n = 7; propionate oxidation in MMA, 15.2 to 64.8 mumol/kg/h, and in PA, 11.1 to 36.0, control 5.1 to 19.0, n = 5). By contrast, in vivo leucine oxidation was undetectable in three of the four MSUD subjects (less than 0.5 mumol/kg/h) and negligible in the remaining subject (2 mumol/kg/h, control 10.4 to 15.7, n = 6). These results suggest that significant substrate removal can be achieved in some inborn metabolic errors either through stimulation of residual enzyme activity in defective enzyme systems or by activation of alternate metabolic pathways. Both possibilities almost certainly depend on gross elevation of substrate concentrations. By contrast, only minimal in vivo oxidation of leucine appears possible in MSUD

  14. Colorimetric detection of urea, urease, and urease inhibitor based on the peroxidase-like activity of gold nanoparticles.

    Science.gov (United States)

    Deng, Hao-Hua; Hong, Guo-Lin; Lin, Feng-Lin; Liu, Ai-Lin; Xia, Xing-Hua; Chen, Wei

    2016-04-07

    Herein, we reported for the first time that gold nanoparticles-catalyzed 3,3',5,5'-tetramethylbenzidine-H2O2 system can serve as an ultrasensitive colorimetric pH indicator. Gold nanoparticles acted as a catalyst and imitated the function of horseradish peroxidase. The absorbance at 450 nm of the yellow-color product in the catalytic reaction exhibited a linear fashion over the pH range of 6.40-6.60. On the basis of this property, we constructed a novel sensing platform for the determination of urea, urease, and urease inhibitor. The limit of detection for urea and urease was 5 μM and 1.8 U/L, respectively. The half-maximal inhibition value IC50 of acetohydroxamic acid was found to be 0.05 mM. Urea in human urine and urease in soil were detected with satisfied results. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Piper nigrum: micropropagation, antioxidative enzyme activities, and chromatographic fingerprint analysis for quality control.

    Science.gov (United States)

    Ahmad, Nisar; Abbasi, Bilal Haider; Rahman, Inayat ur; Fazal, Hina

    2013-04-01

    A reliable in vitro regeneration system for the economical and medicinally important Piper nigrum L. has been established. Callus and shoot regeneration was encouraged from leaf portions on Murashige and Skoog (MS) medium augmented with varied concentrations of plant growth regulators. A higher callus production (90 %) was observed in explants incubated on MS medium incorporated with 1.0 mg L(-1) 6-benzyladenine (BA) along with 0.5 mg L(-1) gibberellic acid after 4 weeks of culture. Moreover, a callogenic response of 85 % was also recorded for 1.0 mg L(-1) BA in combination with 0.25 mg L(-1) α-naphthalene acetic acid (NAA) and 0.25 mg L(-1) 2,4-dichlorophenoxyacetic acid or 0.5 mg L(-1) indole butyric acid (IBA) along with 0.25 mg L(-1) NAA and indole acetic acid. Subsequent sub-culturing of callus after 4 weeks of culture onto MS medium supplemented with 1.5 mg L(-1) thiodiazoran or 1.5 mg L(-1) IBA induced 100 % shoot response. Rooted plantlets were achieved on medium containing varied concentrations of auxins. The antioxidative enzyme activities [superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX)] revealed that significantly higher SOD was observed in regenerated plantlets than in other tissues. However, POD, CAT, and APX were higher in callus than in other tissues. A high-performance liquid chromatography (HPLC) fingerprint analysis protocol was established for quality control in different in vitro-regenerated tissues of P. nigrum L. During analysis, most of the common peaks represent the active principle "piperine." The chemical contents, especially piperine, showed variation from callus culture to whole plantlet regeneration. Based on the deviation in chromatographic peaks, the in vitro-regenerated plantlets exhibit a nearly similar piperine profile to acclimated plantlets. The in vitro regeneration system and HPLC fingerprint analysis established here brought a novel approach to the quality control of in vitro

  16. The catalytic activity of Ag{sub 2}S-montmorillonites as peroxidase mimetic toward colorimetric detection of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qingyun, E-mail: qyliu@sdust.edu.cn [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Jiang, Yanling; Zhang, Leyou; Zhou, Xinpei [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Lv, Xintian [School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252000 (China); Ding, Yanyuan; Sun, Lifang; Chen, Pengpeng [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Yin, Hailiang [Academy of Science & Technology, China University of Petroleum, Dongying 257061 (China)

    2016-08-01

    Nanocomposites based on silver sulfide (Ag{sub 2}S) and Ca-montmorillonite (Ca{sup 2+}-MMT) were synthesized by a simple hydrothermal method. The nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectra (FTIR). The as-prepared Ag{sub 2}S-MMT nanocomposites were firstly demonstrated to possess intrinsic peroxidase-like activity and could rapidly catalytically oxidize the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H{sub 2}O{sub 2} to produce a blue product which can be seen by the naked eye in only one minute. The experimental results revealed that the Ag{sub 2}S-MMT nanocomposites exhibit higher thermal durance. Based on the TMB–H{sub 2}O{sub 2} catalyzed color reaction, the Ag{sub 2}S-MMT nanocomposites were exploited as a new type of biosensor for detection and estimation of H{sub 2}O{sub 2} through a simple, cheap and selective colorimetric method. - Highlights: • Ag{sub 2}S – montmorillonites (MMT) was synthesized by a facile one step method. • The as-prepared Ag{sub 2}S-MMT nanocomposites firstly demonstrate to possess intrinsic peroxidase-like activity. • Ag{sub 2}S-MMT nanocomposites showed highly catalytic activity. • Ag{sub 2}S-MMT could rapidly catalytically oxidize substrates TMB in the presence of H{sub 2}O{sub 2} in 1 min. • The catalytic mechanism is from the generation of hydroxyl radical (·OH) decomposed from H{sub 2}O{sub 2}.

  17. Enzyme stabilization for pesticide degradation

    Energy Technology Data Exchange (ETDEWEB)

    Rivers, D.B.; Frazer, F.R. III; Mason, D.W.; Tice, T.R.

    1988-01-01

    Enzymes offer inherent advantages and limitations as active components of formulations used to decontaminate soil and equipment contaminated with toxic materials such as pesticides. Because of the catalytic nature of enzymes, each molecule of enzyme has the potential to destroy countless molecules of a contaminating toxic compound. This degradation takes place under mild environmental conditions of pH, temperature, pressure, and solvent. The basic limitation of enzymes is their degree of stability during storage and application conditions. Stabilizing methods such as the use of additives, covalent crosslinking, covalent attachment, gel entrapment, and microencapsulation have been directed developing an enzyme preparation that is stable under extremes of pH, temperature, and exposure to organic solvents. Initial studies were conducted using the model enzymes subtilisin and horseradish peroxidase.

  18. Comparison of plasma malondialdehyde, glutathione, glutathione peroxidase, hydroxyproline and selenium levels in patients with vitiligo and healthy controls

    Directory of Open Access Journals (Sweden)

    Ozturk I

    2008-01-01

    Full Text Available Background: The etiology and pathophysiologic mechanism of vitiligo are still unclear. The relationship between increased oxidative stress due to the accumulation of radicals and reactive oxygen species and the associated changes in blood and epidermal component of vitiliginous skin have been reported many times. We investigated the possible changes of plasma malondialdehyde, glutathione, selenium, hydroxyproline and glutathione peroxidase activity levels in patients with vitiligo in order to evaluate the relationship between oxidative stress and etiopathogenesis of vitiligo. Materials and Methods: Plasma malondialdehyde, glutathione, hydroxyproline and glutathione peroxidase activity levels were measured by spectrophotometric methods, and HPLC was used for measurement of selenium concentrations. Results: Our results showed increased malondialdehyde, hydroxyproline and glutathione peroxidase activity levels in plasma of vitiligo group ( P < 0.05. Conclusion: Support of antioxidant system via nonenzymatic antioxidant compounds and antioxidant enzymes may be useful to prevent of melanocyte degeneration which occur due to oxidative damage in vitiligo.

  19. Effects of chilled storage and cryopreservation on sperm characteristics, antioxidant enzyme activities, and lipid peroxidation in Pacific cod Gadus microcephalus

    Science.gov (United States)

    Wang, Xueying; Shi, Xuehui; Liu, Yifan; Yu, Daode; Guan, Shuguang; Liu, Qinghua; Li, Jun

    2016-07-01

    The present study evaluated the effects of chilled storage and cryopreservation on sperm motion characteristics, antioxidant enzyme activities, and lipid peroxidation in the Pacific cod Gadus macrocephalus. Sperm motility and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (Gr), and lipid peroxidation (measured via malondialdehyde (MDA) content) were determined after the milt was stored at 4°C for 12 h, cryopreserved without cryoprotectant in 12% propylene glycol (PG), cryopreserved in 12% PG+0.1 mol/L trehalose, or cryopreserved in 12% PG spermatozoa but centrifuged to decant the supernatant prior to cryopreservation (only sperm cells were cryopreserved). After chilled storage or cryopreservation, the SOD, CAT and GPx activities were reduced in sperm cells and increased in seminal plasma in almost all treatments; sperm motility parameters were also decreased. However, the addition of trehalose into the cryoprotectant could significantly improve the postthaw sperm quality as revealed by the sperm average path velocity. This improvement might be attributed to the function of trehalose in scavenging reactive oxygen species. Chilled storage and cryopreservation had significant effects on sperm motion characteristics, antioxidant enzyme activities, and lipid peroxidation in the Pacific cod.

  20. Mining anaerobic digester consortia metagenomes for secreted carbohydrate active enzymes

    DEFF Research Database (Denmark)

    Wilkens, Casper; Busk, Peter Kamp; Pilgaard, Bo

    thermophilic and mesophilic ADs a wide variety of carbohydrate active enzyme functions were discovered in the metagenomic sequencing of the microbial consortia. The most dominating type of glycoside hydrolases were β-glucosidases (up to 27%), α-amylases (up to 10%), α-glucosidases (up to 8%), α......, and food wastes (Alvarado et al., 2014). The processes and the roles of the microorganisms that are involved in biomass conversion and methane production in ADs are still not fully understood. We are investigating thermophilic and mesophilic ADs that use wastewater surplus sludge for methane production...... was done with the Peptide Pattern Recognition (PPR) program (Busk and Lange, 2013), which is a novel non-alignment based approach that can predict function of e.g. CAZymes. PPR identifies a set of short conserved sequences, which can be used as a finger print when mining genomes for novel enzymes. In both...

  1. Understanding drivers of peatland extracellular enzyme activity in the PEATcosm experiment: mixed evidence for enzymic latch hypothesis

    Science.gov (United States)

    Karl J. Romanowicz; Evan S. Kane; Lynette R. Potvin; Aleta L. Daniels; Randy Kolka; Erik A. Lilleskov

    2015-01-01

    Aims. Our objective was to assess the impacts of water table position and plant functional groups on peatland extracellular enzyme activity (EEA) framed within the context of the enzymic latch hypothesis. Methods. We utilized a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional...

  2. DNA-directed control of enzyme-inhibitor complex formation: a modular approach to reversibly switch enzyme activity

    NARCIS (Netherlands)

    Janssen, B.M.G.; Engelen, W.; Merkx, M.

    2015-01-01

    DNA-templated reversible assembly of an enzyme–inhibitor complex is presented as a new and highly modular approach to control enzyme activity. TEM1-ß-lactamase and its inhibitor protein BLIP were conjugated to different oligonucleotides, resulting in enzyme inhibition in the presence of template

  3. Protein-directed in situ synthesis of platinum nanoparticles with superior peroxidase-like activity, and their use for photometric determination of hydrogen peroxide

    International Nuclear Information System (INIS)

    Chen, Lijian; Wang, Nan; Wang, Xindong; Ai, Shiyun

    2013-01-01

    Platinum nanoparticles (Pt-NPs) with sizes in the range from 10 to 30 nm were synthesized using protein-directed one-pot reduction. The model globular protein bovine serum albumin (BSA) was exploited as the template, and the resulting BSA/Pt-NPs were studied by transmission electron microscopy, energy dispersive X-ray spectroscopy, and resonance Rayleigh scattering spectroscopy. The modified nanoparticles display a peroxidase-like activity that was exploited in a rapid method for the colorimetric determination of hydrogen peroxide which can be detected in the 50 μM to 3 mM concentration range. The limit of detection is 7.9 μM, and the lowest concentration that can be visually detected is 200 μM. (author)

  4. Substrate-Competitive Activity-Based Profiling of Ester Prodrug Activating Enzymes.

    Science.gov (United States)

    Xu, Hao; Majmudar, Jaimeen D; Davda, Dahvid; Ghanakota, Phani; Kim, Ki H; Carlson, Heather A; Showalter, Hollis D; Martin, Brent R; Amidon, Gordon L

    2015-09-08

    Understanding the mechanistic basis of prodrug delivery and activation is critical for establishing species-specific prodrug sensitivities necessary for evaluating preclinical animal models and potential drug-drug interactions. Despite significant adoption of prodrug methodologies for enhanced pharmacokinetics, functional annotation of prodrug activating enzymes is laborious and often unaddressed. Activity-based protein profiling (ABPP) describes an emerging chemoproteomic approach to assay active site occupancy within a mechanistically similar enzyme class in native proteomes. The serine hydrolase enzyme family is broadly reactive with reporter-linked fluorophosphonates, which have shown to provide a mechanism-based covalent labeling strategy to assay the activation state and active site occupancy of cellular serine amidases, esterases, and thioesterases. Here we describe a modified ABPP approach using direct substrate competition to identify activating enzymes for an ethyl ester prodrug, the influenza neuraminidase inhibitor oseltamivir. Substrate-competitive ABPP analysis identified carboxylesterase 1 (CES1) as an oseltamivir-activating enzyme in intestinal cell homogenates. Saturating concentrations of oseltamivir lead to a four-fold reduction in the observed rate constant for CES1 inactivation by fluorophosphonates. WWL50, a reported carbamate inhibitor of mouse CES1, blocked oseltamivir hydrolysis activity in human cell homogenates, confirming CES1 is the primary prodrug activating enzyme for oseltamivir in human liver and intestinal cell lines. The related carbamate inhibitor WWL79 inhibited mouse but not human CES1, providing a series of probes for analyzing prodrug activation mechanisms in different preclinical models. Overall, we present a substrate-competitive activity-based profiling approach for broadly surveying candidate prodrug hydrolyzing enzymes and outline the kinetic parameters for activating enzyme discovery, ester prodrug design, and

  5. Structure and Heme-Independent Peroxidase Activity of a Fully-Coordinated Mononuclear Mn(II) Complex with a Schiff-Base Tripodal Ligand Containing Three Imidazole Groups

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Shuranjan; Lee, Hong In [Kyungpook National University, Daegu (Korea, Republic of); Moon, Do Hyun [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Lah, Myoung Soo [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2010-11-15

    New complex [Mn(II)H{sub 1.5}L]{sub 2}[Mn(II)H{sub 3}L]{sub 2}(ClO{sub 4}){sub 5}·3H{sub 2}O, where H{sub 3}L is tris{2-(4-imidazolyl)methyliminoethyl} amine (imtren), has been prepared by reacting manganese(II) perchlorate hexahydrate with the imtren ligand in methanol. X-ray crystallographic study revealed that the imtren ligand hexadentately binds to Mn(II) ion through the three Schiff-base imine N atoms and three imidazole N atoms with a distorted octahedral geometry, and the apical tertiary amine N atom of the ligand pseudo-coordinates to Mn(II), forming overall a pseudo-seven coordination environment. The hydrogen-bonds between imidazole and imidazolate of [Mn(II)H{sub 1.5}L]{sup 0.5+} complex ions are extended to build a 2D puckered network with trigonal voids. [Mn(II)H{sub 3}L]{sup 2+} complex ions constitutes another extended 2D puckered layer without hydrogen bonds. Two layers are wedged each other to constitute overall stack of the crystal. Peroxidase activity of complex 1 was examined by observing the oxidation of 2,2'-azinobis(3-ethylbenzothiazoline)- 6-sulfonic acid (ABTS) with hydrogen peroxide in the presence of complex 1. Generation of ABTS{sup +·} was observed by UV-vis and EPR spectroscopies, indicating that the complex 1, a fully-coordinated mononuclear Mn(II) complex with nitrogen-only ligand, has a heme-independent peroxidase activity.

  6. Isolation, characterization and transcriptome analysis of a novel Antarctic Aspergillus sydowii strain MS-19 as a potential lignocellulosic enzyme source.

    Science.gov (United States)

    Cong, Bailin; Wang, Nengfei; Liu, Shenghao; Liu, Feng; Yin, Xiaofei; Shen, Jihong

    2017-05-30

    With the growing demand for fossil fuels and the severe energy crisis, lignocellulose is widely regarded as a promising cost-effective renewable resource for ethanol production, and the use of lignocellulose residues as raw material is remarkable. Polar organisms have important value in scientific research and development for their novelty, uniqueness and diversity. In this study, a fungus Aspergillus sydowii MS-19, with the potential for lignocellulose degradation was screened out and isolated from an Antarctic region. The growth profile of Aspergillus sydowii MS-19 was measured, revealing that Aspergillus sydowii MS-19 could utilize lignin as a sole carbon source. Its ability to synthesize low-temperature lignin peroxidase (Lip) and manganese peroxidase (Mnp) enzymes was verified, and the properties of these enzymes were also investigated. High-throughput sequencing was employed to identify and characterize the transcriptome of Aspergillus sydowii MS-19. Carbohydrate-Active Enzymes (CAZyme)-annotated genes in Aspergillus sydowii MS-19 were compared with those in the brown-rot fungus representative species, Postia placenta and Penicillium decumbens. There were 701CAZymes annotated in Aspergillus sydowii MS-19, including 17 cellulases and 19 feruloyl esterases related to lignocellulose-degradation. Remarkably, one sequence annotated as laccase was obtained, which can degrade lignin. Three peroxidase sequences sharing a similar structure with typical lignin peroxidase and manganese peroxidase were also found and annotated as haem-binding peroxidase, glutathione peroxidase and catalase-peroxidase. In this study, the fungus Aspergillus sydowii MS-19 was isolated and shown to synthesize low-temperature lignin-degrading enzymes: lignin peroxidase (Lip) and manganese peroxidase (Mnp). These findings provide useful information to improve our understanding of low-temperature lignocellulosic enzyme production by polar microorganisms and to facilitate research and

  7. Effects of the hepatocarcinogen nafenopin, a peroxisome proliferator, on the activities of rat liver glutathione-requiring enzymes and catalase in comparison to the action of phenobarbital.

    Science.gov (United States)

    Furukawa, K; Numoto, S; Furuya, K; Furukawa, N T; Williams, G M

    1985-10-01

    The biochemical effects in the livers of male rats of prolonged administration of the experimental hepatocarcinogen nafenopin, a hypolipidemic agent and peroxisome proliferator, were compared to those of another experimental liver carcinogen, phenobarbital, which acts as a neoplasm promoter. Feeding of nafenopin, 0.03 mmol/kg basal diet for up to 24 weeks increased the numbers of hepatic peroxisomes, increased catalase activity, markedly decreased cytosolic glutathione transferase activities toward two substrates, decreased cytosolic glutathione peroxidase activities toward H2O2 and two organic peroxides, and suppressed the age-related increase in gamma-glutamyl transpeptidase activity. In contrast the livers of rats fed an equimolar concentration of phenobarbital displayed increases in cytosolic glutathione transferase activities and enhancement of gamma-glutamyl transpeptidase activity but no changes in glutathione peroxidase activities. There was also an enhancement of catalase activity without apparent increase in peroxisome number. Enzyme kinetic analyses revealed that the cytosolic glutathione transferase activities toward two halogenonitrobenzene substrates were inhibited in the rats fed nafenopin and displayed elevated Km and decreased Vmax. Kinetic studies of glutathione transferase activities in which nafenopin was mixed with normal rat liver cytosols in the assay system revealed competitive type inhibition toward 1-chloro-2,4-dinitrobenzene and a noncompetitive type of inhibition toward 3,4-dichloronitrobenzene. Likewise activities of glutathione peroxidases toward H2O2 and cumene hydroperoxide were suppressed by in vitro addition. Thus the effects of nafenopin and phenobarbital on liver biochemistry were very different. The inhibition of hepatic biotransformation and scavenger systems by nafenopin is suggested to be relevant to its hepatocarcinogenicity.

  8. Response of hydrolytic enzyme activities and nitrogen mineralization to fertilizer and organic matter application in subtropical paddy soils

    Science.gov (United States)

    Kader, Mohammed Abdul; Yeasmin, Sabina; Akter, Masuda; Sleutel, Steven

    2016-04-01

    Driving controllers of nitrogen (N) mineralization in paddy soils, especially under anaerobic soil conditions, remain elusive. The influence of exogenous organic matter (OM) and fertilizer application on the activities of five relevant enzymes (β-glucosaminidase, β-glucosidase, L-glutaminase, urease and arylamidase) was measured in two long-term field experiments. One 18-years field experiment was established on a weathered terrace soil with a rice-wheat crop rotation at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) having five OM treatments combined with two mineral N fertilizer levels. Another 30-years experiment was established on a young floodplain soil with rice-rice crop rotation at the Bangladesh Agricultural University (BAU) having eight mineral fertilizer treatments combined with organic manure. At BSMRAU, N fertilizer and OM amendments significantly increased all enzyme activities, suggesting them to be primarily determined by substrate availability. At BAU, non-responsiveness of β-glucosidase activity suggested little effect of the studied fertilizer and OM amendments on general soil microbial activity. Notwithstanding probably equal microbial demand for N, β-glucosaminidase and L-glutaminase activities differed significantly among the treatments (P>0.05) and followed strikingly opposite trends and correlations with soil organic N mineralization. So enzymatic pathways to acquire N differed by treatment at BAU, indicating differences in soil N quality and bio-availability. L-glutaminase activity was significantly positively correlated to the aerobic and anaerobic N mineralization rates at both field experiments. Combined with negative correlations between β-glucosaminidase activity and N mineralization rates, it appears that terminal amino acid NH2 hydrolysis was a rate-limiting step for soil N mineralization at BAU. Future investigations with joint quantification of polyphenol accumulation and binding of N, alongside an

  9. Selenium concentrations and enzyme activities of glutathione metabolism in wild long-tailed ducks and common eiders

    Science.gov (United States)

    Franson, J. Christian; Hoffman, David J.; Flint, Paul L.

    2011-01-01

    The relationships of selenium (Se) concentrations in whole blood with plasma activities of total glutathione peroxidase, Se-dependent glutathione peroxidase, and glutathione reductase were studied in long-tailed ducks (Clangula hyemalis) and common eiders (Somateria mollissima) sampled along the Beaufort Sea coast of Alaska, USA. Blood Se concentrations were >8 μg/g wet weight in both species. Linear regression revealed that the activities of total and Se-dependent glutathione peroxidase were significantly related to Se concentrations only in long-tailed ducks, raising the possibility that these birds were experiencing early oxidative stress.

  10. ACTIVITY OF SUPEROXIDE DISMUTASE ENZYME IN YEAST SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Blažena Lavová

    2014-02-01

    Full Text Available Reactive oxygen species (ROS with reactive nitrogen species (RNS are known to play dual role in biological systems, they can be harmful or beneficial to living systems. ROS can be important mediators of damage to cell structures, including proteins, lipids and nucleic acids termed as oxidative stress. The antioxidant enzymes protect the organism against the oxidative damage caused by active oxygen forms. The role of superoxide dismutase (SOD is to accelerate the dismutation of the toxic superoxide radical, produced during oxidative energy processes, to hydrogen peroxide and molecular oxygen. In this study, SOD activity of three yeast strains Saccharomyces cerevisiae was determined. It was found that SOD activity was the highest (23.7 U.mg-1 protein in strain 612 after 28 hours of cultivation. The lowest SOD activity from all tested strains was found after 56 hours of cultivation of strain Gyöng (0.7 U.mg-1 protein.

  11. Mineralisation of 14C-labelled synthetic lignin and ligninolytic enzyme activities of litter-decomposing basidiomycetous fungi.

    Science.gov (United States)

    Steffen, K T; Hofrichter, M; Hatakka, A

    2000-12-01

    Within a screening program, 27 soil litter-decomposing basidiomycetes were tested for ligninolytic enzyme activities using agar-media containing 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate), a humic acid or Mn2+ ions as indicator substrates. Most active species were found within the family Strophariaceae (Agrocybe praecox, Stropharia coronilla, S. rugosoannulata) and used for mineralisation experiments with a 14C-ring-labelled synthetic lignin (14C-DHP). The fungi mineralised around 25% of the lignin to 14CO2 within 12 weeks of incubation in a straw environment; about 20% of the lignin was converted to water-soluble fragments. Mn-peroxidase was found to be the predominant ligninolytic enzyme of all three fungi in liquid culture and its production was strongly enhanced in the presence of Mn2+ ions. The results of this study demonstrate that certain ubiquitous litter-decomposing basidiomycetes possess ligninolytic activities similar to the wood-decaying white-rot fungi, the most efficient lignin degraders in nature.

  12. Cadmium toxicity affects chlorophyll a and b content, antioxidant enzyme activities and mineral nutrient accumulation in strawberry

    Directory of Open Access Journals (Sweden)

    Ferhad Muradoglu

    2015-01-01

    Full Text Available BACKGROUND: Cadmium (Cd is well known as one of the most toxic metals affecting the environment and can severely restrict plant growth and development. In this study, Cd toxicities were studied in strawberry cv. Camarosa using pot experiment. Chlorophyll and malondialdehyde (MDA contents, catalase (CAT, superoxide dismutase (SOD, ascorbate peroxidase (APX activities and mineral nutrient concentrations were investigated in both roots and leaves of strawberry plant after exposure Cd. RESULTS: Cd content in both roots and leaves was increased with the application of increasing concentrations of Cd. We found higher Cd concentration in roots rather than in leaves. Chlorophyll a and b was decreased in leaves but MDA significantly increased under increased Cd concentration treatments in both roots and leaves. SOD and CAT activities was also increased with the increase Cd concentrations. K, Mn and Mg concentrations were found higher in leaves than roots under Cd stress. In general, increased Cd treatments increased K, Mg, Fe, Ca, Cu and Zn concentration in both roots and leaves. Excessive Cd treatments reduced chlorophyll contents, increased antioxidant enzyme activities and changes in plant nutrition concentrations in both roots and leaves. CONCLUSION: The results presented in this work suggested that Cd treatments have negative effect on chlorophyll content and nearly decreased 30% of plant growth in strawberry. Strawberry roots accumulated higher Cd than leaves. We found that MDA and antioxidant enzyme (CAT, SOD and APX contents may have considered a good indicator in determining Cd tolerance in strawberry plant.

  13. Hierarchical hybrid peroxidase catalysts for remediation of phenol wastewater

    KAUST Repository

    Duan, Xiaonan

    2014-02-20

    We report a new family of hierarchical hybrid catalysts comprised of horseradish peroxidase (HRP)-magnetic nanoparticles for advanced oxidation processes and demonstrate their utility in the removal of phenol from water. The immobilized HRP catalyzes the oxidation of phenols in the presence of H2O2, producing free radicals. The phenoxy radicals react with each other in a non-enzymatic process to form polymers, which can be removed by precipitation with salts or condensation. The hybrid peroxidase catalysts exhibit three times higher activity than free HRP and are able to remove three times more phenol from water compared to free HRP under similar conditions. In addition, the hybrid catalysts reduce substrate inhibition and limit inactivation from reaction products, which are common problems with free or conventionally immobilized enzymes. Reusability is improved when the HRP-magnetic nanoparticle hybrids are supported on micron-scale magnetic particles, and can be retained with a specially designed magnetically driven reactor. The performance of the hybrid catalysts makes them attractive for several industrial and environmental applications and their development might pave the way for practical applications by eliminating most of the limitations that have prevented the use of free or conventionally immobilized enzymes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Hierarchical hybrid peroxidase catalysts for remediation of phenol wastewater

    KAUST Repository

    Duan, Xiaonan; Corgié , Sté phane C.; Aneshansley, Daniel J.; Wang, Peng; Walker, Larry P.; Giannelis, Emmanuel P.

    2014-01-01

    We report a new family of hierarchical hybrid catalysts comprised of horseradish peroxidase (HRP)-magnetic nanoparticles for advanced oxidation processes and demonstrate their utility in the removal of phenol from water. The immobilized HRP catalyzes the oxidation of phenols in the presence of H2O2, producing free radicals. The phenoxy radicals react with each other in a non-enzymatic process to form polymers, which can be removed by precipitation with salts or condensation. The hybrid peroxidase catalysts exhibit three times higher activity than free HRP and are able to remove three times more phenol from water compared to free HRP under similar conditions. In addition, the hybrid catalysts reduce substrate inhibition and limit inactivation from reaction products, which are common problems with free or conventionally immobilized enzymes. Reusability is improved when the HRP-magnetic nanoparticle hybrids are supported on micron-scale magnetic particles, and can be retained with a specially designed magnetically driven reactor. The performance of the hybrid catalysts makes them attractive for several industrial and environmental applications and their development might pave the way for practical applications by eliminating most of the limitations that have prevented the use of free or conventionally immobilized enzymes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Extracellular enzyme activity assay as indicator of soil microbial functional diversity and activity

    DEFF Research Database (Denmark)

    Hendriksen, Niels Bohse; Winding, Anne

    2012-01-01

    Extracellular enzyme activity assay as indicator of soil microbial functional diversity and activity Niels Bohse Hendriksen, Anne Winding. Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark Soils provide numerous essential ecosystem services such as carbon cycling...... of soil microbial functions is still needed. In soil, enzymes originate from a variety of organisms, notably fungi and bacteria and especially hydrolytic extracellular enzymes are of pivotal importance for decomposition of organic substrates and biogeochemical cycling. Their activity will reflect...... the functional diversity and activity of the microorganisms involved in decomposition processes. Their activity has been measured by the use of fluorogenic model substrates e.g. methylumbelliferyl (MUF) substrates for a number of enzymes involved in the degradation of polysacharides as cellulose, hemicellulose...

  16. Degradation of direct azo dye by Cucurbita pepo free and immobilized peroxidase.

    Science.gov (United States)

    Boucherit, Nabila; Abouseoud, Mahmoud; Adour, Lydia

    2013-06-01

    Enzymatic decolourization of the azo dye, Direct Yellow (DY106) by Cucurbita pepo (courgette) peroxidase (CP) is a complex process, which is greatly affected by pH, temperature, enzyme activity and the concentrations of H2O2 and dye. Courgette peroxidase was extracted and its performance was evaluated by using the free-CP (FCP) and immobilized-CP (ICP) forms in the decolourization of DY106. Immobilization of peroxidase in calcium alginate beads was performed according to a strategy aiming to minimize enzyme leakage and keep its activity at a maximum value by optimizing sodium alginate content, enzyme loading and calcium chloride concentration. The initial conditions at which the highest DY106 decolourization yield was obtained were found at pH 2, temperature 20 degrees C, H2O2 dose 1 mmol/L (FCP) and 100 mmol/L (ICP). The highest decolourization rates were obtained for dye concentrations 50 mg/L (FCP) and 80 mg/L (ICP). Under optimal conditions, the FCP was able to decolorize more than 87% of the dye within 2 min. While with ICP, the decolourization yield was 75% within 15 min. The decolourization and removal of DY106 was proved by UV-Vis analysis. Fourier transform infrared (FT-IR) spectroscopy analysis was also performed on DY106 and enzymatic treatment precipitated byproduct.

  17. Glycine post-synthetic modification of MIL-53(Fe) metal-organic framework with enhanced and stable peroxidase-like activity for sensitive glucose biosensing.

    Science.gov (United States)

    Dong, Wenfei; Yang, Liaoyuan; Huang, Yuming

    2017-05-15

    A facile and rapid post-synthetic strategy was proposed to prepare a glycine functionalized MIL-53(Fe), namely glycine-MIL-53(Fe), by a simple mixing of water dispersible MIL-53(Fe) and glycine. The FT-IR, SEM, XRD and zeta potential were used to characterize the glycine-MIL-53(Fe). The result showed that glycine post-synthetic modification of MIL-53(Fe) did not change in the morphology and crystal structure of MIL-53(Fe). Interestingly, compared with MIL-53(Fe), the glycine-MIL-53(Fe) exhibits an enhanced peroxidase-like activity, which could catalyze the oxidation of TMB by H 2 O 2 to produce an intensive color reaction. Kinetic analysis indicated that the K m of glycine-MIL-53(Fe) for TMB was one-tenth of that of MIL-53(Fe). The glycine-MIL-53(Fe) as peroxidase mimetic displays better stability under alkaline or acidic conditions than MIL-53(Fe). The good performance of glycine-MIL-53(Fe) over MIL-53(Fe) may be attributed to the increase of affinity between TMB and the glycine-MIL-53(Fe). With these characteristics, a simple and sensitive method was developed for the detection of H 2 O 2 and glucose. The linear detection range for H 2 O 2 is 0.10-10μM with a detection limit of 49nM, and glucose could be linearly detected in the range from 0.25 to 10μM with a detection limit of 0.13μM. The proposed method was successfully used for glucose detection in human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Virtual Biochemistry – pH effect on enzyme activity

    Directory of Open Access Journals (Sweden)

    D.N. Heidrich

    2011-04-01

    Full Text Available Protocols of laboratory experiments, followed by teacher's explanation, not always clearly translate to the student the dynamics to beadopted for the implementation of the proposed practice. One of these cases is related to the study of the effect of pH on enzyme activity. For better help the understanding of the technical procedure, a hypermedia was built based on a protocol adopted at the Department of Biochemistry, UFSC. The hypermedia shows how theeffect of variations in pH can be observed  in vitro. Taking as example salivary amylase and the consumption of starch (substrate by means of iodine staining, a set of pH buffers was tested to identify the best pH for this enzyme  activity. This hypermedia as introductory tool for such practice was tested on aNutrition course classroom. Students agree that the hypermedia provided a better understanding of the proposed activities. Teachers also notice a smallerreagents consumption and reduction of the time spent by the students in the achievement of the experiment.

  19. Antibacterial and glucosyltransferase enzyme inhibitory activity of helmyntostachyszelanica

    Science.gov (United States)

    Kuspradini, H.; Putri, AS; Mitsunaga, T.

    2018-04-01

    Helminthostachyszeylanica is a terrestrial, herbaceous, fern-like plant of southeastern Asia and Australia, commonly known as tunjuk-langit. This kind of plant have a medicinal properties such as treatment of malaria, dysentery and can be eaten with betel in the treatment of whooping cough. To evaluate the scientific basis for the use of the plant, the antimicrobial activities of extracts of the stem and leaves were evaluated. The bacteria used in this study is Streptococcus sobrinus, a species of gram-positive, that may be associated with human dental caries. The dried powdered plant parts were extracted using methanol and 50% aqueous extract and screened for their antibacterial effects of Streptococcus sobrinus using the 96 well-plate microdilution broth method. The inhibitory activities of its related enzyme were also determined. The plant extracts showed variable antibacterial and Glucosyltransferase enzyme inhibitory activity while some extracts could not cause any inhibition. It was shown that 50% ethanolics of Helminthostachyzeylanica stem have a potency as anti dental caries agents.

  20. Influence of altered precipitation pattern on greenhouse gas emissions and soil enzyme activities in Pannonian soils

    Science.gov (United States)

    Forstner, Stefan Johannes; Michel, Kerstin; Berthold, Helene; Baumgarten, Andreas; Wanek, Wolfgang; Zechmeister-Boltenstern, Sophie; Kitzler, Barbara

    2013-04-01

    water only once in two weeks (D=dry). Both groups received same water totals for each soil. At the end of each two week drying period, greenhouse gas fluxes were measured via an open-chamber-system (CO2, NO) and a closed-chamber-approach (CH4, N2O, CO2). Additional cylinders were harvested destructively to quantify inorganic N forms, microbial biomass C, N and extracellular enzyme activity (Cellulase, Xylanase, Protease, Phenoloxidase, Peroxidase). We hypothesize that after rewetting (1) rates of greenhouse gas fluxes will generally increase, as well as (2) extracellular enzyme activity indicating enhanced microbial activity. However, response may be different for gases and enzymes involved in the C and N cycle, respectively, as drying/rewetting stress may uncouple microbial mediated biogeochemical cycles. Results will be presented at the EGU General Assembly. Reference: Schimel, J., Balser, T.C., and Wallenstein, M. (2007). Microbial stress-response physiology and its implications for ecosystem function. Ecology 88, 1386-1394.

  1. Protein stability and enzyme activity at extreme biological temperatures

    International Nuclear Information System (INIS)

    Feller, Georges

    2010-01-01

    Psychrophilic microorganisms thrive in permanently cold environments, even at subzero temperatures. To maintain metabolic rates compatible with sustained life, they have improved the dynamics of their protein structures, thereby enabling appropriate molecular motions required for biological activity at low temperatures. As a consequence of this structural flexibility, psychrophilic proteins are unstable and heat-labile. In the upper range of biological temperatures, thermophiles and hyperthermophiles grow at temperatures > 100 0 C and synthesize ultra-stable proteins. However, thermophilic enzymes are nearly inactive at room temperature as a result of their compactness and rigidity. At the molecular level, both types of extremophilic proteins have adapted the same structural factors, but in opposite directions, to address either activity at low temperatures or stability in hot environments. A model based on folding funnels is proposed accounting for the stability-activity relationships in extremophilic proteins. (topical review)

  2. Optimized Production of Lignin Peroxidase, Manganese Peroxidase

    African Journals Online (AJOL)

    Mgina

    submerged culture fermentations were investigated for maximum enzymes ... 0.18, 4.44 and 593 U/ml, respectively compared to 0.0011, 0.0054 and 2.3 U/ml .... (2004) studied some Tanzanian white rot ... were done in 500 ml Erlenmeyer flasks and ... rotary shaker at 125 rpm. ..... bioreactor cultures (Hess et al., 2002). From.

  3. Site- and horizon-specific patterns of microbial community structure and enzyme activities in permafrost-affected soils of Greenland

    Science.gov (United States)

    Gittel, Antje; Bárta, Jiří; Kohoutová, Iva; Schnecker, Jörg; Wild, Birgit; Čapek, Petr; Kaiser, Christina; Torsvik, Vigdis L.; Richter, Andreas; Schleper, Christa; Urich, Tim

    2014-01-01

    Permafrost-affected soils in the Northern latitudes store huge amounts of organic carbon (OC) that is prone to microbial degradation and subsequent release of greenhouse gasses to the atmosphere. In Greenland, the consequences of permafrost thaw have only recently been addressed, and predictions on its impact on the carbon budget are thus still highly uncertain. However, the fate of OC is not only determined by abiotic factors, but closely tied to microbial activity. We investigated eight soil profiles in northeast Greenland comprising two sites with typical tundra vegetation and one wet fen site. We assessed microbial community structure and diversity (SSU rRNA gene tag sequencing, quantification of bacteria, archaea and fungi), and measured hydrolytic and oxidative enzyme activities. Sampling site and thus abiotic factors had a significant impact on microbial community structure, diversity and activity, the wet fen site exhibiting higher potential enzyme activities and presumably being a hot spot for anaerobic degradation processes such as fermentation and methanogenesis. Lowest fungal to bacterial ratios were found in topsoils that had been relocated by cryoturbation (“buried topsoils”), resulting from a decrease in fungal abundance compared to recent (“unburied”) topsoils. Actinobacteria (in particular Intrasporangiaceae) accounted for a major fraction of the microbial community in buried topsoils, but were only of minor abundance in all other soil horizons. It was indicated that the distribution pattern of Actinobacteria and a variety of other bacterial classes was related to the activity of phenol oxidases and peroxidases supporting the hypothesis that bacteria might resume the role of fungi in oxidative enzyme production and degradation of phenolic and other complex substrates in these soils. Our study sheds light on the highly diverse, but poorly-studied communities in permafrost-affected soils in Greenland and their role in OC degradation. PMID

  4. Lifestyle predictors of oxidant and antioxidant enzyme activities and total antioxidant capacity in healthy women: a cross-sectional study.

    Science.gov (United States)

    Mahasneh, Amjad A; Zhang, Yali; Zhao, Hua; Ambrosone, Christine B; Hong, Chi-Chen

    2016-12-01

    The aim of this study was to identify demographic and modifiable lifestyle factors that may be related to endogenous oxidant and antioxidant activity measured in blood specimens from putatively healthy women recruited at the Roswell Park Cancer Institute (Buffalo, NY, USA). Total glutathione (TGSH), catalase (CAT), CuZn-superoxide dismutase (CuZn-SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and myeloperoxidase (MPO) activity, and total antioxidant capacity (TAC) were measured in 124 healthy women, and associations with epidemiological factors were tested using general linear models. There were significant differences in oxidant and antioxidant enzyme activities according to lifestyle factors, after adjusting for duration of blood storage and season of blood draw. Compared to women who consumed ≤2.8 servings of fruits and vegetables daily, those consuming >5.3 servings had on average 31 % lower MPO activity (p-trend = 0.02), as a marker of oxidative stress, 16 % higher antioxidant GPx activity (p-trend = 0.08), and 9 % higher TAC (p-trend = 0.05). Obese women (body mass index, BMI ≥ 30) in contrast showed 17 % lower antioxidant GPx activity, 44 % higher MPO activity (p-trend = 0.03), and 10 % higher TAC (p-trend = 0.03) compared to women with normal BMI lifestyle factors and, therefore, may be potentially modifiable, with implications for risk reduction of chronic conditions related to oxidative stress.

  5. Enhanced visible-light-induced photocatalytic activity of α-Fe2O3 adsorbing redox enzymes

    Directory of Open Access Journals (Sweden)

    Kai Kamada

    2015-03-01

    Full Text Available We report fabrication of hybrid photocatalyst composed of an n-type semiconductor (α-Fe2O3 and a redox enzyme (horseradish peroxidase; HRP, and its performance for oxidation of luminol in an aqueous solution. The hybrid photocatalyst is simply formed via physical adsorption of HRP to an α-Fe2O3 sintered body. Under visible light irradiation, the bare α-Fe2O3 with a narrow bandgap photocatalytically oxidizes luminol along with blue emission that can be used as an indicator of the photocatalytic performance. The blue emission is largely strengthened after the adsorption of HRP, demonstrating that the presence of enzyme improves apparent photocatalytic activity of α-Fe2O3. The favorable effect is derived from synergistic oxidation of luminol by the biocatalysts (HRP as well as by the photocatalyst (α-Fe2O3. In this paper, influence of excitation wavelength, adsorption amount of HRP, and reaction temperature on the overall photocatalytic activity are elucidated, and then a reaction mechanism of the proposed novel hybrid photocatalyst is discussed in detail.

  6. Comparison of antioxidant enzyme activities and DNA damage in chickpea (Cicer arietinum L.) genotypes exposed to vanadium.

    Science.gov (United States)

    Imtiaz, Muhammad; Mushtaq, Muhammad Adnan; Rizwan, Muhammad Shahid; Arif, Muhammad Saleem; Yousaf, Balal; Ashraf, Muhammad; Shuanglian, Xiong; Rizwan, Muhammad; Mehmood, Sajid; Tu, Shuxin

    2016-10-01

    The present study was done to elucidate the effects of vanadium (V) on photosynthetic pigments, membrane damage, antioxidant enzymes, protein, and deoxyribonucleic acid (DNA) integrity in the following chickpea genotypes: C-44 (tolerant) and Balkasar (sensitive). Changes in these parameters were strikingly dependent on levels of V, at 60 and 120 mg V L(-1) induced DNA damage in Balkasar only, while photosynthetic pigments and protein were decreased from 15 to 120 mg V L(-1) and membrane was also damaged. It was shown that photosynthetic pigments and protein production declined from 15 to 120 mg V L(-1) and the membrane was also damaged, while DNA damage was not observed at any level of V stress in C-44. Moreover, the antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were increased in both genotypes of chickpea against V stress; however, more activities were observed in C-44 than Balkasar. The results suggest that DNA damage in sensitive genotypes can be triggered due to exposure of higher vanadium.

  7. Disruption of AtWNK8 Enhances Tolerance of Arabidopsis to Salt and Osmotic Stresses via Modulating Proline Content and Activities of Catalase and Peroxidase

    Directory of Open Access Journals (Sweden)

    Hong Liao

    2013-03-01

    Full Text Available With no lysine kinases (WNKs play important roles in plant growth and development. However, its role in salt and osmotic stress tolerance is unclear. Here, we report that AtWNK8 is mainly expressed in primary root, hypocotyl, stamen and pistil and is induced by NaCl and sorbitol treatment. Compared to the wild-type, the T-DNA knock-out wnk8 mutant was more tolerant to severe salinity and osmotic stresses, as indicated by 27% and 198% more fresh weight in the NaCl and sorbitol treatment, respectively. The wnk8 mutant also accumulated 1.43-fold more proline than the wild-type in the sorbitol treatment. Under NaCl and sorbitol stresses, catalase (CAT activity in wnk8 mutant was 1.92- and 3.7-times of that in Col-0, respectively. Similarly, under salt and osmotic stress conditions, peroxidase (POD activities in wnk8 mutant were 1.81- and 1.58-times of that in Col-0, respectively. Taken together, we revealed that maintaining higher CAT and POD activities might be one of the reasons that the disruption of AtWNK8 enhances the tolerance to salt stress, and accumulating more proline and higher activities of CAT and POD might result in the higher tolerance of WNK8 to osmotic stress.

  8. Dietary fish oil replacement with palm or poultry oil increases fillet oxidative stability and decreases liver glutathione peroxidase activity in barramundi (Lates calcarifer).

    Science.gov (United States)

    Wan Ahmad, Wan A R; Stone, David A J; Schuller, Kathryn A

    2013-12-01

    Complete dietary fish oil replacement with palm or poultry oil in barramundi (Lates calcarifer) had no detrimental effects on growth or hepatosomatic index of juvenile fish up to an average size of ~50 g. However, it significantly decreased the omega-3 (n-3) long-chain polyunsaturated fatty acid content of the fish muscle (fillet) lipids. This was particularly true for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which are recognised for their health beneficial effects in the human diet. As a result of their decreased EPA and DHA content, the peroxidation index of the muscle lipids was also decreased. This was associated with increased simulated retail storage shelf life as indicated by decreased thiobarbituric acid reactive substances in muscle samples from fish fed the palm or poultry oil-based diets. Concomitantly, glutathione peroxidase (GPx) activity, but not glutathione S-transferase (GST) activity or reduced glutathione concentration, was significantly reduced in the liver of barramundi fed the palm or poultry oil-based diets as compared with the fish fed the fish oil-based diet. Furthermore, GPx and GST activity were very low in muscle, much lower than in gastrointestinal tract, liver or swim bladder. Therefore, we propose that liver GPx activity may be a good predictor of fillet shelf life in barramundi and other fish species.

  9. A modern mode of activation for nucleic acid enzymes.

    Directory of Open Access Journals (Sweden)

    Dominique Lévesque

    2007-07-01

    Full Text Available Through evolution, enzymes have developed subtle modes of activation in order to ensure the sufficiently high substrate specificity required by modern cellular metabolism. One of these modes is the use of a target-dependent module (i.e. a docking domain such as those found in signalling kinases. Upon the binding of the target to a docking domain, the substrate is positioned within the catalytic site. The prodomain acts as a target-dependent module switching the kinase from an off state to an on state. As compared to the allosteric mode of activation, there is no need for the presence of a third partner. None of the ribozymes discovered to date have such a mode of activation, nor does any other known RNA. Starting from a specific on/off adaptor for the hepatitis delta virus ribozyme, that differs but has a mechanism reminiscent of this signalling kinase, we have adapted this mode of activation, using the techniques of molecular engineering, to both catalytic RNAs and DNAs exhibiting various activities. Specifically, we adapted three cleaving ribozymes (hepatitis delta virus, hammerhead and hairpin ribozymes, a cleaving 10-23 deoxyribozyme, a ligating hairpin ribozyme and an artificially selected capping ribozyme. In each case, there was a significant gain in terms of substrate specificity. Even if this mode of control is unreported for natural catalytic nucleic acids, its use needs not be limited to proteinous enzymes. We suggest that the complexity of the modern cellular metabolism might have been an important selective pressure in this evolutionary process.

  10. Impact of chlortetracycline and sulfapyridine antibiotics on soil enzyme activities

    Science.gov (United States)

    Molaei, Ali; Lakzian, Amir; Datta, Rahul; Haghnia, Gholamhosain; Astaraei, Alireza; Rasouli-Sadaghiani, MirHassan; Ceccherini, Maria T.

    2017-10-01

    Pharmaceutical antibiotics are frequently used in the livestock and poultry industries to control infectious diseases. Due to the lack of proper guidance for use, the majority of administrated antibiotics and their metabolites are excreted to the soil environment through urine and feces. In the present study, we used chlortetracycline and sulfapyridine antibiotics to screen out their effects on dehydrogenase, alkaline phosphatase and urease activity. Factorial experiments were conducted with different concentrations of antibiotic (0, 10, 25 and 100 mg kg-1 of soil) mixed with soil samples, and the enzyme activity was measured at intervals of 1, 4 and 21 days. The results show that the chlortetracycline and sulfapyridine antibiotics negatively affect the dehydrogenase activity, but the effect of sulfapyridine decreases with time of incubation. Indeed, sulfapyridine antibiotic significantly affect the alkaline phosphatase activity for the entire three-time interval, while chlortetracycline seems to inhibit its activity within 1 and 4 days of incubation. The effects of chlortetracycline and sulfapyridine antibiotics on urease activity appear similar, as they both significantly affect the urease activity on day 1 of incubation. The present study concludes that chlortetracycline and sulfapyridine antibiotics have harmful effects on soil microbes, with the extent of effects varying with the duration of incubation and the type of antibiotics used.

  11. Hyperthyroidism in Patients with Graves' Ophthalmopathy, and Thyroidal, Skeletal and Eye Muscle Specific Type 2 Deiodinase Enzyme Activities.

    Science.gov (United States)

    Molnár, Ildikó; Szentmiklósi, József A; Somogyiné-Vári, Éva

    2017-09-01

    Graves' ophthalmopathy is characterized by hyperthyroidism, which is associated with higher serum T 3 levels than T 4 due to deiodinase enzymes.The effect of Graves' patient's sera (n=52) with elevated thyroid hormone and TSH receptor or thyroid peroxidase antibody (anti-TPO) levels was investigated on thyroidal, skeletal and eye muscle type 2 deiodinase enzyme (DII) activities. DII activities were measured with 125 I-T 4 substrate, while thyroid hormone and antibody levels with immunoassays.In Graves' ophthalmopathy, sera with elevated FT 4 or FT 3 levels reduced DII activites remarkably in all tissue fractions. Thyroidal DII activities were lower than those using eye muscle fraction (0.6±0.22 vs 1.14±0.43 pmol/mg/min, PEffect of sera with increased FT 3 levels demonstrated also reduced DII activities in patients with Graves' ophthalmopathy after methimazole therapy compared to those who had no ophthalmopathy (2.88±2 vs 20.42±11.82 pmol/mg/min, PHyperthyroid sera with TSH receptor antibodies resulted in increased DII activities, while sera with anti-TPO antibodies were connected to lower DII activities in Graves' ophthalmopathy.In summary, the actions of hyperthyroid sera derived from patients with Graves' disease were tested on tissue-specific DII activities. Elevated FT 4 level-induced DII inactivation is present in Graves' ophthalmopathy, which seems to be also present at the beginning of methimazole therapy. Stimulating TSH receptor antibiodies increased DII activities via their nongenomic effects using sera of hyperthyroid Graves' ophthalmopathy, but anti-TPO antibodies could influence DII activities via altering FT 4 levels. © Georg Thieme Verlag KG Stuttgart · New York.

  12. Optimization of Ligninolytic Enzyme Activity and Production Rate with Ceriporiopsis subvermispora for Application in Bioremediation by Varying Submerged Media Composition and Growth Immobilization Support

    Directory of Open Access Journals (Sweden)

    Janja Babič

    2012-09-01

    Full Text Available Response surface methodology (central composite design of experiments was employed to simultaneously optimize enzyme production and productivities of two ligninolytic enzymes produced by Ceriporiopsis subvermispora. Concentrations of glucose, ammonium tartrate and Polysorbate 80 were varied to establish the optimal composition of liquid media (OLM, where the highest experimentally obtained activities and productivities were 41 U L−1 and 16 U L−1 day−1 for laccase (Lac, and 193 U L−1 and 80 U L−1 day−1 for manganese peroxidase (MnP. Considering culture growth in OLM on various types of immobilization support, the best results were obtained with 1 cm beech wood cubes (BWCM. Enzyme activities in culture filtrate were 152 U L−1 for Lac and 58 U L−1 for MnP, since the chemical composition of this immobilization material induced higher Lac activity. Lower enzyme activities were obtained with polyurethane foam. Culture filtrates of OLM and BWCM were applied for dye decolorization. Remazol Brilliant Blue R (RBBR was decolorized faster and more efficiently than Copper(IIphthalocyanine (CuP with BWCM (80% and 60%, since Lac played a crucial role. Decolorization of CuP was initially faster than that of RBBR, due to higher MnP activities in OLM. The extent of decolorization after 14 h was 60% for both dyes.

  13. Changes of Enzymes Activity and Production of Secondary Metabolites of Artemisia aucheri in Different Altitudes and Its Relation to Adaptation

    Directory of Open Access Journals (Sweden)

    Hassan Zare-maivan

    2014-08-01

    Full Text Available Artemisia plants are the most abundant plants species in Iran which contain strong antioxidant properties and as such, have medicinal and economic value. Despite wide distribution of Artemisisa species, ecophysiology of its adaptation to changes in altitude and soil property had not been investigated. In this study, the relationships between ecophysiological and adaptation capabilities of A. aucheri to altitude changes through measuring changes in the activity of its antioxidant enzymes and secondary metabolites in situ was investigated based on a completely randomized experiment. The enzyme activities of superoxide dismutase, catalase, peroxidase, and the amount of total phenolics, flavonoids, anthocyanins, malondialdehyde and chlorophylls A and B were measured in A. aucheri plants growing in three different altitudes at and above the 36° latitude on the southern slopes of Eastern Alborz Mountain ranges in triplicate 10*10 m quadrates. Statistical analysis of data showed that soil type was loamy significantly becoming more sandy- loam with lowering in altitude and the soil contained greater amounts of oxides of silicone, aluminum, magnesium, sodium, potassium and phosphorus in upper altitude except calcium which was present in greater quantity in lower altitude. With increasing altitude, activity of superoxide dismutase and quantities of chlorophylls and total phenols in leaves increased. Some biochemical factors in A. aucheri showed significant positive correlation(P ≤ 0.05 between them. Adaptation of A. aucheri to changes in altitude occurred through changing its antioxidant enzymes activity and production of secondary metabolites in response to factors related to the altitude including soil type and texture, moisture level, temperature and most importantly radiation

  14. Effects of Heat Acclimation on Photosynthesis, Antioxidant Enzyme Activities, and Gene Expression in Orchardgrass under Heat Stress

    Directory of Open Access Journals (Sweden)

    Xin Xin Zhao

    2014-09-01

    Full Text Available The present study was designed to examine the effects of heat acclimation on enzymatic activity, transcription levels, the photosynthesis processes associated with thermostability in orchardgrass (Dactylis glomerata L..The stomatal conductance (Gs, net photosynthetic rate (Pn, and transpiration rates (Tr of both heat-acclimated (HA and non-acclimated (NA plants were drastically reduced during heat treatment [using a 5-day heat stress treatment (38/30 °C ‒ day/night followed by a 3-day recovery under control conditions (25/20 °C ‒ day/night, in order to consolidate the second cycle was permitted]. Water use efficiency increased more steeply in the HA (4.9 times versus the NA (1.8 times plants, and the intercellular CO2 concentration decreased gently in NA (10.9% and HA (25.3% plants after 20 d of treatments compared to 0 days’. Furthermore, heat-acclimated plants were able to maintain significant activity levels of superoxide disumutase (SOD, catalase (CAT, guaiacol peroxidase (POD, and transcription levels of genes encoding these enzymes; in addition, HA plants displayed lower malondialdehyde content and lower electrolyte leakage than NA plants. These results suggest that maintenance of activity and transcription levels of antioxidant enzymes as well as photosynthesis are associated with variable thermostability in HA and NA plants. This likely occurs through cellular membrane stabilization and improvements in water use efficiency in the photosynthetic process during heat stress. The association between antioxidant enzyme activity and gene expression, both of which may vary with genetic variation in heat tolerance, is important to further understand the molecular mechanisms that contribute to heat tolerance.

  15. Puromycin-sensitive aminopeptidase: an antiviral prodrug activating enzyme.

    Science.gov (United States)

    Tehler, Ulrika; Nelson, Cara H; Peterson, Larryn W; Provoda, Chester J; Hilfinger, John M; Lee, Kyung-Dall; McKenna, Charles E; Amidon, Gordon L

    2010-03-01

    Cidofovir (HPMPC) is a broad-spectrum antiviral agent, currently used to treat AIDS-related human cytomegalovirus retinitis. Cidofovir has recognized therapeutic potential for orthopox virus infections, although its use is hampered by its inherent low oral bioavailability. Val-Ser-cyclic HPMPC (Val-Ser-cHPMPC) is a promising peptide prodrug which has previously been shown by us to improve the permeability and bioavailability of the parent compound in rodent models (Eriksson et al., 2008. Molecular Pharmaceutics 5, 598-609). Puromycin-sensitive aminopeptidase was partially purified from Caco-2 cell homogenates and identified as a prodrug activating enzyme for Val-Ser-cHPMPC. The prodrug activation process initially involves an enzymatic step where the l-Valine residue is removed by puromycin-sensitive aminopeptidase, a step that is bestatin-sensitive. Subsequent chemical hydrolysis results in the generation of cHPMPC. A recombinant puromycin-sensitive aminopeptidase was generated and its substrate specificity investigated. The k(cat) for Val-pNA was significantly lower than that for Ala-pNA, suggesting that some amino acids are preferred over others. Furthermore, the three-fold higher k(cat) for Val-Ser-cHPMPC as compared to Val-pNA suggests that the leaving group may play an important role in determining hydrolytic activity. In addition to its ability to hydrolyze a variety of substrates, these observations strongly suggest that puromycin-sensitive aminopeptidase is an important enzyme for activating Val-Ser-cHPMPC in vivo. Taken together, our data suggest that puromycin-sensitive aminopeptidase makes an attractive target for future prodrug design.

  16. Influence of thermal treatment on color, enzyme activities, and antioxidant capacity of innovative pastelike parsley products.

    Science.gov (United States)

    Kaiser, Andrea; Brinkmann, Maike; Carle, Reinhold; Kammerer, Dietmar R

    2012-03-28

    Conventional spice powders are often characterized by low sensory quality and high microbial loads. Furthermore, genuine enzymes are only inhibited but not entirely inactivated upon drying, so that they may regain their activity upon rehydration of dried foods. To overcome these problems, initial heating was applied in the present study as the first process step for the production of innovative pastelike parsley products. For this purpose, fresh parsley was blanched (80, 90, and 100 °C for 1-10 min) and subsequently comminuted to form a paste. Alternatively, mincing was carried out prior to heat treatment. Regardless of temperature, the color of the latter product did not show any change after heating for 1 min. With progressing exposure time the green color turned to olive hues due to marked pheophytin formation. Inactivation of genuine peroxidase (POD) and polyphenol oxidase (PPO) was achieved at all temperature-time regimes applied. In contrast, the parsley products obtained after immediate water-blanching were characterized by brighter green colors and enhanced pigment retention. With the exception of the variants water-blanched at 80 °C, POD and PPO were completely inactivated at any of the thermal treatments. Furthermore, in water-blanched samples, antioxidant capacities as determined by the TEAC and FRAP assays were even enhanced compared to unheated parsley, whereas a decrease of phenolic contents could not be prevented. Consequently, the innovative process presented in this study allows the production of novel herb and spice products characterized by improved sensory quality as compared to conventional spice products.

  17. County-Scale Spatial Distribution of Soil Enzyme Activities and Enzyme Activity Indices in Agricultural Land: Implications for Soil Quality Assessment

    Directory of Open Access Journals (Sweden)

    Xiangping Tan

    2014-01-01

    Full Text Available Here the spatial distribution of soil enzymatic properties in agricultural land was evaluated on a county-wide (567 km2 scale in Changwu, Shaanxi Province, China. The spatial variations in activities of five hydrolytic enzymes were examined using geostatistical methods. The relationships between soil enzyme activities and other soil properties were evaluated using both an integrated total enzyme activity index (TEI and the geometric mean of enzyme activities (GME. At the county scale, soil invertase, phosphatase, and catalase activities were moderately spatially correlated, whereas urease and dehydrogenase activities were weakly spatially correlated. Correlation analysis showed that both TEI and GME were better correlated with selected soil physicochemical properties than single enzyme activities. Multivariate regression analysis showed that soil OM content had the strongest positive effect while soil pH had a negative effect on the two enzyme activity indices. In addition, total phosphorous content had a positive effect on TEI and GME in orchard soils, whereas alkali-hydrolyzable nitrogen and available potassium contents, respectively, had negative and positive effects on these two enzyme indices in cropland soils. The results indicate that land use changes strongly affect soil enzyme activities in agricultural land, where TEI provides a sensitive biological indicator for soil quality.

  18. Phlorotannins from Alaskan Seaweed Inhibit Carbolytic Enzyme Activity

    Directory of Open Access Journals (Sweden)

    Joshua Kellogg

    2014-10-01

    Full Text Available Global incidence of type 2 diabetes has escalated over the past few decades, necessitating a continued search for natural sources of enzyme inhibitors to offset postprandial hyperglycemia. The objective of this study was to evaluate coastal Alaskan seaweed inhibition of α-glucosidase and α-amylase, two carbolytic enzymes involved in serum glucose regulation. Of the six species initially screened, the brown seaweeds Fucus distichus and Alaria marginata possessed the strongest inhibitory effects. F. distichus fractions were potent mixed-mode inhibitors of α-glucosidase and α-amylase, with IC50 values of 0.89 and 13.9 μg/mL, respectively; significantly more efficacious than the pharmaceutical acarbose (IC50 of 112.0 and 137.8 μg/mL, respectively. The activity of F. distichus fractions was associated with phlorotannin oligomers. Normal-phase liquid chromatography-mass spectrometry (NPLC-MS was employed to characterize individual oligomers. Accurate masses and fragmentation patterns confirmed the presence of fucophloroethol structures with degrees of polymerization from 3 to 18 monomer units. These findings suggest that coastal Alaskan seaweeds are sources of α-glucosidase and α-amylase inhibitory phlorotannins, and thus have potential to limit the release of sugar from carbohydrates and thus alleviate postprandial hyperglycemia.

  19. Assaying Oxidative Coupling Activity of CYP450 Enzymes.

    Science.gov (United States)

    Agarwal, Vinayak

    2018-01-01

    Cytochrome P450 (CYP450) enzymes are ubiquitous catalysts in natural product biosynthetic schemes where they catalyze numerous different transformations using radical intermediates. In this protocol, we describe procedures to assay the activity of a marine bacterial CYP450 enzyme Bmp7 which catalyzes the oxidative radical coupling of polyhalogenated aromatic substrates. The broad substrate tolerance of Bmp7, together with rearrangements of the aryl radical intermediates leads to a large number of products to be generated by the enzymatic action of Bmp7. The complexity of the product pool generated by Bmp7 thus presents an analytical challenge for structural elucidation. To address this challenge, we describe mass spectrometry-based procedures to provide structural insights into aryl crosslinked products generated by Bmp7, which can complement subsequent spectroscopic experiments. Using the procedures described here, for the first time, we show that Bmp7 can efficiently accept polychlorinated aryl substrates, in addition to the physiological polybrominated substrates for the biosynthesis of polyhalogenated marine natural products. © 2018 Elsevier Inc. All rights reserved.

  20. Phlorotannins from Alaskan Seaweed Inhibit Carbolytic Enzyme Activity

    Science.gov (United States)

    Kellogg, Joshua; Grace, Mary H.; Lila, Mary Ann

    2014-01-01

    Global incidence of type 2 diabetes has escalated over the past few decades, necessitating a continued search for natural sources of enzyme inhibitors to offset postprandial hyperglycemia. The objective of this study was to evaluate coastal Alaskan seaweed inhibition of α-glucosidase and α-amylase, two carbolytic enzymes involved in serum glucose regulation. Of the six species initially screened, the brown seaweeds Fucus distichus and Alaria marginata possessed the strongest inhibitory effects. F. distichus fractions were potent mixed-mode inhibitors of α-glucosidase and α-amylase, with IC50 values of 0.89 and 13.9 μg/mL, respectively; significantly more efficacious than the pharmaceutical acarbose (IC50 of 112.0 and 137.8 μg/mL, respectively). The activity of F. distichus fractions was associated with phlorotannin oligomers. Normal-phase liquid chromatography-mass spectrometry (NPLC-MS) was employed to characterize individual oligomers. Accurate masses and fragmentation patterns confirmed the presence of fucophloroethol structures with degrees of polymerization from 3 to 18 monomer units. These findings suggest that coastal Alaskan seaweeds are sources of α-glucosidase and α-amylase inhibitory phlorotannins, and thus have potential to limit the release of sugar from carbohydrates and thus alleviate postprandial hyperglycemia. PMID:25341030

  1. DUOX enzyme activity promotes AKT signalling in prostate cancer cells.

    Science.gov (United States)

    Pettigrew, Christopher A; Clerkin, John S; Cotter, Thomas G

    2012-12-01

    Reactive oxygen species (ROS) and oxidative stress are related to tumour progression, and high levels of ROS have been observed in prostate tumours compared to normal prostate. ROS can positively influence AKT signalling and thereby promote cell survival. The aim of this project was to establish whether the ROS generated in prostate cancer cells positively regulate AKT signalling and enable resistance to apoptotic stimuli. In PC3 cells, dual oxidase (DUOX) enzymes actively generate ROS, which inactivate phosphatases, thereby maintaining AKT phosphorylation. Inhibition of DUOX by diphenylene iodium (DPI), intracellular calcium chelation and small-interfering RNA (siRNA) resulted in lower ROS levels, lower AKT and glycogen synthase kinase 3β (GSK3β) phosphorylation, as well as reduced cell viability and increased susceptibility to apoptosis stimulating fragment (FAS) induced apoptosis. This report shows that ROS levels in PC3 cells are constitutively maintained by DUOX enzymes, and these ROS positively regulate AKT signalling through inactivating phosphatases, leading to increased resistance to apoptosis.

  2. Enzyme architecture: deconstruction of the enzyme-activating phosphodianion interactions of orotidine 5'-monophosphate decarboxylase.

    Science.gov (United States)

    Goldman, Lawrence M; Amyes, Tina L; Goryanova, Bogdana; Gerlt, John A; Richard, John P

    2014-07-16

    The mechanism for activation of orotidine 5'-monophosphate decarboxylase (OMPDC) by interactions of side chains from Gln215 and Try217 at a gripper loop and R235, adjacent to this loop, with the phosphodianion of OMP was probed by determining the kinetic parameters k(cat) and K(m) for all combinations of single, double, and triple Q215A, Y217F, and R235A mutations. The 12 kcal/mol intrinsic binding energy of the phosphodianion is shown to be equal to the sum of the binding energies of the side chains of R235 (6 kcal/mol), Q215 (2 kcal/mol), Y217 (2 kcal/mol), and hydrogen bonds to the G234 and R235 backbone amides (2 kcal/mol). Analysis of a triple mutant cube shows small (ca. 1 kcal/mol) interactions between phosphodianion gripper side chains, which are consistent with steric crowding of the side chains around the phosphodianion at wild-type OMPDC. These mutations result in the same change in the activation barrier to the OMPDC-catalyzed reactions of the whole substrate OMP and the substrate pieces (1-β-D-erythrofuranosyl)orotic acid (EO) and phosphite dianion. This shows that the transition states for these reactions are stabilized by similar interactions with the protein catalyst. The 12 kcal/mol intrinsic phosphodianion binding energy of OMP is divided between the 8 kcal/mol of binding energy, which is utilized to drive a thermodynamically unfavorable conformational change of the free enzyme, resulting in an increase in (k(cat))(obs) for OMPDC-catalyzed decarboxylation of OMP, and the 4 kcal/mol of binding energy, which is utilized to stabilize the Michaelis complex, resulting in a decrease in (K(m))(obs).

  3. Preparation of a Superhydrophobic and Peroxidase-like Activity Array Chip for H2O2 Sensing by Surface-Enhanced Raman Scattering.