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Sample records for copper amine oxidase

  1. Inhibition of chickpea seedling copper amine oxidases by tetraethylenepentamine

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    Sona Talaei

    2012-01-01

    Full Text Available Copper amine oxidases are important enzymes, which contribute to the regulation of mono- and polyamine levels. Each monomer contains one Cu(II ion and 2,4,5-trihydroxyphenylalanine (TPQ as cofactors. They catalyze the oxidative deamination of primary amines to aldehydes with a ping-pong mechanism consisting of a transamination. The mechanism is followed by the transfer of two electrons to molecular oxygen which is reduced to hydrogen peroxide. Inhibitors are important tools in the study of catalytic properties of copper amine oxidases and they also have a wide application in physiological research. In this study, purification of the chickpea seedling amine oxidase, was done via salting out by ammonium sulfate and dialysis, followed by DEAE-cellulose column chromatography. By using the Lineweaver - Burk plot, the Km and Vm of the enzyme were found to be 3.3 mM and 0.95 mmol/min/mg, respectively. In this study, the interaction of chickpea diamino oxidase with tetraethylene- pentamine was studied. Analysis of kinetic data indicated that tetraethylenepentamine (with Ki=0.1 mM inhibits the enzyme by linear mixed inhibitory effect.

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

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

    2005-02-10

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

  3. The Apoplastic Copper AMINE OXIDASE1 Mediates Jasmonic Acid-Induced Protoxylem Differentiation in Arabidopsis Roots.

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    Ghuge, Sandip A; Carucci, Andrea; Rodrigues-Pousada, Renato A; Tisi, Alessandra; Franchi, Stefano; Tavladoraki, Paraskevi; Angelini, Riccardo; Cona, Alessandra

    2015-06-01

    Polyamines are involved in key developmental processes and stress responses. Copper amine oxidases oxidize the polyamine putrescine (Put), producing an aldehyde, ammonia, and hydrogen peroxide (H2O2). The Arabidopsis (Arabidopsis thaliana) amine oxidase gene At4g14940 (AtAO1) encodes an apoplastic copper amine oxidase expressed at the early stages of vascular tissue differentiation in roots. Here, its role in root development and xylem differentiation was explored by pharmacological and forward/reverse genetic approaches. Analysis of the AtAO1 expression pattern in roots by a promoter::green fluorescent protein-β-glucuronidase fusion revealed strong gene expression in the protoxylem at the transition, elongation, and maturation zones. Methyl jasmonate (MeJA) induced AtAO1 gene expression in vascular tissues, especially at the transition and elongation zones. Early protoxylem differentiation was observed upon MeJA treatment along with Put level decrease and H2O2 accumulation in wild-type roots, whereas Atao1 loss-of-function mutants were unresponsive to the hormone. The H2O2 scavenger N,N(1)-dimethylthiourea reversed the MeJA-induced early protoxylem differentiation in wild-type seedlings. Likewise, Put, which had no effect on Atao1 mutants, induced early protoxylem differentiation in the wild type, this event being counteracted by N,N(1)-dimethylthiourea treatment. Consistently, AtAO1-overexpressing plants showed lower Put levels and early protoxylem differentiation concurrent with H2O2 accumulation in the root zone where the first protoxylem cells with fully developed secondary wall thickenings are found. These results show that the H2O2 produced via AtAO1-driven Put oxidation plays a role in MeJA signaling leading to early protoxylem differentiation in root. © 2015 American Society of Plant Biologists. All Rights Reserved.

  4. Reactions of copper(II)-phenol systems with O2: models for TPQ biosynthesis in copper amine oxidases.

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    Tabuchi, Kae; Ertem, Mehmed Z; Sugimoto, Hideki; Kunishita, Atsushi; Tano, Tetsuro; Fujieda, Nobutaka; Cramer, Christopher J; Itoh, Shinobu

    2011-03-01

    Copper(II) complexes supported by a series of phenol-containing bis(pyridin-2-ylmethyl)amine N(3) ligands (denoted as L(o)H, L(m)H, and L(p)H) have been synthesized, and their O(2) reactivity has been examined in detail to gain mechanistic insights into the biosynthesis of the TPQ cofactor (2,4,5-trihydroxyphenylalaninequinone, TOPA quinone) in copper-containing amine oxidases. The copper(II) complex of L(o)H (ortho-phenol derivative) involves a direct phenolate to copper(II) coordination and exhibits almost no reactivity toward O(2) at 60 °C in CH(3)OH. On the other hand, the copper(II) complex of L(m)H (meta-phenol derivative), which does not involve direct coordinative interaction between the phenol moiety and the copper(II) ion, reacts with O(2) in the presence of triethylamine as a base to give a methoxy-substituted para-quinone derivative under the same conditions. The product structure has been established by detailed nuclear magnetic resonance (NMR), infrared (IR) spectroscopy, and electrospray ionization-mass spectroscopy (ESI-MS) (including (18)O-labeling experiment) analyses. Density functional theory predicts that the reaction involves (i) intramolecular electron transfer from the deprotonated phenol (phenolate) to copper(II) to generate a copper(I)-phenoxyl radical; (ii) the addition of O(2) to this intermediate, resulting in an end-on copper(II) superoxide; (iii) electrophilic substitution of the phenolic radical to give a copper(II)-alkylperoxo intermediate; (iv) O-O bond cleavage concomitant with a proton migration, giving a para-quinone derivative; and (v) Michael addition of methoxide from copper(II) to the para-quinone ring and subsequent O(2) oxidation. This reaction sequence is similar to that proposed for the biosynthetic pathway leading to the TPQ cofactor in the enzymatic system. The generated para-quinone derivative can act as a turnover catalyst for aerobic oxidation of benzylamine to N-benzylidene benzylamine. Another type of copper

  5. Expression of a copper-containing amine oxidase by human ciliary body.

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    Howell, D N; Valnickova, Z; Oury, T D; Miller, S E; Sanfilippo, F P; Enghild, J J

    1998-09-08

    To examine the molecular structure and ultrastructural distribution of a novel amine oxidase in human ciliary body. Human ciliary bodies were solubilized with a nonionic detergent. The solubilized material was subjected to affinity chromatography with 2B4.14.1, a monoclonal antibody which recognizes a family of ciliary body glycoproteins. Proteins eluted from the affinity column were further separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Peptides produced from a 2B4.14. 1-reactive protein with an approximate molecular weight of 100 kDa were analyzed by Edman degradation. The protein thus identified was further examined by Western blotting and immunoelectron microscopy with anti-peptide antisera. Peptide sequences from the 100 kDa ciliary body protein were identical to the predicted protein sequence of an amine oxidase identified recently in a human placental cDNA library. The identity of the ciliary body protein was confirmed by Western blotting with rabbit antiserum generated against the predicted carboxy-terminal peptide of human placenta amine oxidase. Western blotting under nonreducing conditions and following glycosidase digestion indicated that the native enzyme is a disulfide-linked homodimer with multiple N-linked oligosaccharide side chains. By immunoelectron microscopy, the ciliary body amine oxidase was localized to the plasma membranes of inner epithelial cells. Human placenta amine oxidase is present on the plasma membranes of ciliary body inner epithelial cells. This finding provides a potential explanation for amine oxidase enzyme activity detected in previous studies of anterior segment tissues. Though the functional role of human placenta amine oxidase in the eye is unclear, it may contribute to the production of H2O2 in aqueous humor.

  6. Limited proteolysis of Hansenula polymorpha yeast amine oxidase: isolation of a C-terminal fragment containing both a copper and quino-cofactor.

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    Plastino, J; Klinman, J P

    1995-09-11

    Limited proteolysis of recombinant Hansenula polymorpha yeast amino oxidase produces a 48 kDa fragment which corresponds to the C-terminal two-thirds of the protein. The fragment contains both TOPA (2,4,5-trihydroxyphenylalanine) and copper, as well as the histidine ligands implicated in copper binding. The fragment is proposed to be the domain responsible for cofactor production in yeast amine oxidase.

  7. COPPER AMINE OXIDASE1 (CuA01)of Arabidopsis thaliana Contributes to Abscisic Acid-and Polyamine-Induced Nitric Oxide Biosynthesis and Abscisic Acid Signal Transduction

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    Rinukshi Wimalasekera; Corina Villar; Tahmina Begum; Günther F. E. Scherer

    2011-01-01

    Polyamines (PA), polyamine oxidases, copper amine oxidases, and nitric oxide (NO)play important roles in physiology and stress responses in plants. NO biosynthesis as a result of catabolism of PA by polyamine oxidases and copper amine oxidases may explain in part PA-mediated responses. Involvement of a copper amine oxidase gene, COPPER AMINE OXIDASE1 (CuA01), of Arabidopsis was tested for its role in stress responses using the knockouts cuaol.1 and cuaol-2. PA-induced and ABA-induced NO production investigated by fluorometry and fluorescence microscopy showed that the cuaol-1 and cuaol-2 are impaired in NO production, suggesting a function of CuAO1 in PA and ABA-mediated NO production. Furthermore, we found a PA-dependent increase in protein S-nitrosylation. The addition of PA and ABA also resulted in HO increases, cuaol-1 and cuaol-2 showed less sensitivity to exogenous ABA supplementation during ger-mination, seedling establishment, and root growth inhibition as compared to wild-type. In response to ABA treatment,expression levels of the stress-responsive genes RD29A and ADH1 were significantly lower in the knockouts. These obser-vations characterize cuaol-1 and cuaol-2 as ABA-insensitive mutants. Taken together, our findings extend the ABA signal transduction network to include CuAO1 as one potential contributor to enhanced NO production by ABA.

  8. Copper-Containing Amine Oxidases and FAD-Dependent Polyamine Oxidases Are Key Players in Plant Tissue Differentiation and Organ Development.

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    Tavladoraki, Paraskevi; Cona, Alessandra; Angelini, Riccardo

    2016-01-01

    Plant polyamines are catabolized by two classes of amine oxidases, the copper amine oxidases (CuAOs) and the flavin adenine dinucleotide (FAD)-dependent polyamine oxidases (PAOs). These enzymes differ to each other in substrate specificity, catalytic mechanism and subcellular localization. CuAOs and PAOs contribute to several physiological processes both through the control of polyamine homeostasis and as sources of biologically-active reaction products. CuAOs and PAOs have been found at high level in the cell-wall of several species belonging to Fabaceae and Poaceae families, respectively, especially in tissues fated to undertake extensive wall loosening/stiffening events and/or in cells undergoing programmed cell death (PCD). Apoplastic CuAOs and PAOs have been shown to play a key role as a source of H2O2 in light- or developmentally-regulated differentiation events, thus influencing cell-wall architecture and maturation as well as PCD. Moreover, growing evidence suggests a key role of intracellular CuAOs and PAOs in several facets of plant development. Here, we discuss recent advances in understanding the contribution of different CuAOs/PAOs, as well as their cross-talk with different intracellular and apoplastic metabolic pathways, in tissue differentiation and organ development.

  9. A comparative study of the binding and inhibition of four copper-containing amine oxidases by azide: implications for the role of copper during the oxidative half-reaction.

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    Juda, Gregory A; Shepard, Eric M; Elmore, Bradley O; Dooley, David M

    2006-07-25

    Copper amine oxidases (CuAOs) catalyze the oxidative deamination of primary amines operating through a ping-pong bi-bi mechanism. In this work, azide (an exogenous monodentate ligand) was used to probe the role of copper during the oxidative half-reaction of CuAO catalysis. The effects of azide on both the reductive and oxidative half-reactions of pea seedling amine oxidase (PSAO), the recombinant human kidney diamine oxidase (rhDAO), Arthrobacter globiformis amine oxidase (AGAO), and Pichia pastoris amine oxidase (PPLO) have been examined. For the reductive half-reaction, defined as the oxidation of amine substrate to an aldehyde, azide was discovered to exhibit either noncompetitive or competitive inhibition with respect to the amine, depending on the enzyme source. With regard to the oxidative half-reaction, defined as the reoxidation of the enzyme via reduction of O(2) to H(2)O(2), azide has been determined to exhibit competitive inhibition with respect to O(2) in PSAO with a calculated K(i) value that is in excellent agreement with the experimentally determined K(d) value for the Cu(II)-N(3)(-) complex. Azide was found to exhibit mixed-type/partially competitive inhibition with respect to substrate O(2) in rhDAO, with an apparent K(i) that is similar to the K(d) value for the Cu(II)-N(3)(-) complex. The competitive inhibition for PSAO and the partially competitive inhibition for rhDAO are consistent with O(2) interacting directly with copper during enzymatic reoxidation. For the enzymes AGAO and PPLO, pure noncompetitive and mixed-type/partially competitive inhibition is observed. K(i) values for reductive and oxidative half-reactions are equivalent and are lower than measured K(d) values for the Cu(II)-N(3)(-) complexes in oxidized and substrate-reduced forms of these enzymes. Given these observations, it appears that substantial inhibition of the reductive half-reaction occurs at the concentrations of azide used for the oxidative half-reaction experiments

  10. The precursor form of Hansenula polymorpha copper amine oxidase 1 in complex with Cu[superscript I] and Co[superscript II

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    Klema, Valerie J.; Johnson, Bryan J.; Klinman, Judith P.; Wilmot, Carrie M. (UMM); (UCB)

    2015-11-30

    Copper amine oxidases (CAOs) catalyze the oxidative deamination of primary amines to their corresponding aldehydes, with the concomitant reduction of O{sub 2} to H{sub 2}O{sub 2}. Catalysis requires two cofactors: a mononuclear copper center and the cofactor 2,4,5-trihydroxyphenylalanine quinone (TPQ). TPQ is synthesized through the post-translational modification of an endogenous tyrosine residue and requires only oxygen and copper to proceed. TPQ biogenesis in CAO can be supported by alternate metals, albeit at decreased rates. A variety of factors are thought to contribute to the degree to which a metal can support TPQ biogenesis, including Lewis acidity, redox potential and electrostatic stabilization capability. The crystal structure has been solved of one of two characterized CAOs from the yeast Hansenula polymorpha (HPAO-1) in its metal-free (apo) form, which contains an unmodified precursor tyrosine residue instead of fully processed TPQ (HPAO-1 was denoted HPAO in the literature prior to 2010). Structures of apoHPAO-1 in complex with Cu{sup I} and Co{sup II} have also been solved, providing structural insight into metal binding prior to biogenesis.

  11. Multiple amine oxidases in cucumber seedlings.

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    Percival, F W; Purves, W K

    1974-10-01

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

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

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

    2015-01-01

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

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

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

    2013-04-10

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

  14. Semicarbazide-sensitive amine oxidase (SSAO): from cell to circulation

    NARCIS (Netherlands)

    F. Boomsma (Frans); H. Hut; U. Bagghoe; A.H. van den Meiracker (Anton)

    2005-01-01

    textabstractSemicarbazide-sensitive amine oxidase (SSAO) is a multi-functional enzyme widely present in nature. It converts primary amines into their corresponding aldehydes, while generating H(2)O(2) and NH(3). In mammals, SSAO circulates in plasma, while a membrane-bound form (of

  15. Semicarbazide-sensitive amine oxidase (SSAO): from cell to circulation

    NARCIS (Netherlands)

    F. Boomsma (Frans); H. Hut; U. Bagghoe; A.H. van den Meiracker (Anton)

    2005-01-01

    textabstractSemicarbazide-sensitive amine oxidase (SSAO) is a multi-functional enzyme widely present in nature. It converts primary amines into their corresponding aldehydes, while generating H(2)O(2) and NH(3). In mammals, SSAO circulates in plasma, while a membrane-bound form

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

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    Sam H Shen

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

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

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

    2007-08-01

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

  18. Bioconversion of Airborne Methylamine by Immobilized Recombinant Amine Oxidase from the Thermotolerant Yeast Hansenula polymorpha

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    Sasi Sigawi

    2014-01-01

    Full Text Available Aliphatic amines, including methylamine, are air-pollutants, due to their intensive use in industry and the natural degradation of proteins, amino acids, and other nitrogen-containing compounds in biological samples. It is necessary to develop systems for removal of methylamine from the air, since airborne methylamine has a negative effect on human health. The primary amine oxidase (primary amine : oxygen oxidoreductase (deaminating or amine oxidase, AMO; EC 1.4.3.21, a copper-containing enzyme from the thermotolerant yeast Hansenula polymorpha which was overexpressed in baker’s yeast Saccharomyces cerevisiae, was tested for its ability to oxidize airborne methylamine. A continuous fluidized bed bioreactor (CFBR was designed to enable bioconversion of airborne methylamine by AMO immobilized in calcium alginate (CA beads. The results demonstrated that the bioreactor with immobilized AMO eliminates nearly 97% of the airborne methylamine. However, the enzymatic activity of AMO causes formation of formaldehyde. A two-step bioconversion process was therefore proposed. In the first step, airborne methylamine was fed into a CFBR which contained immobilized AMO. In the second step, the gas flow was passed through another CFBR, with alcohol oxidase from the yeast H. polymorpha immobilized in CA, in order to decompose the formaldehyde formed in the first step. The proposed system provided almost total elimination of the airborne methylamine and the formaldehyde.

  19. Catalytically active bovine serum amine oxidase bound to fluorescent and magnetically drivable nanoparticles

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    Bidollari E

    2012-05-01

    Full Text Available Giulietta Sinigaglia1, Massimiliano Magro1, Giovanni Miotto1, Sara Cardillo1, Enzo Agostinelli2,3, Radek Zboril4, Eris Bidollari2,3, Fabio Vianello11Department of Biological Chemistry, University of Padua, Padua, Italy; 2Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Biochemical Sciences "A. Rossi Fanelli", SAPIENZA University of Rome, Rome, Italy; 3CNR, Institute Biology and Molecular Pathology, Rome, Italy; 4Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Palacky University, Olomouc, Czech RepublicAbstract: Novel superparamagnetic surface-active maghemite nanoparticles (SAMNs characterized by a diameter of 10 ± 2 nm were modified with bovine serum amine oxidase, which used rhodamine B isothiocyanate (RITC adduct as a fluorescent spacer-arm. A fluorescent and magnetically drivable adduct comprised of bovine serum copper-containing amine oxidase (SAMN–RITC–BSAO that immobilized on the surface of specifically functionalized magnetic nanoparticles was developed. The multifunctional nanomaterial was characterized using transmission electron microscopy, infrared spectroscopy, mass spectrometry, and activity measurements. The results of this study demonstrated that bare magnetic nanoparticles form stable colloidal suspensions in aqueous solutions. The maximum binding capacity of bovine serum amine oxidase was approximately 6.4 mg g-1 nanoparticles. The immobilization procedure reduced the catalytic activity of the native enzyme to 30% ± 10% and the Michaelis constant was increased by a factor of 2. We suggest that the SAMN–RITC–BSAO complex, characterized by a specific activity of 0.81 IU g-1, could be used in the presence of polyamines to create a fluorescent magnetically drivable H2O2 and aldehydes-producing system. Selective tumor cell destruction is suggested as a potential future application of this system.Keywords: amine oxidase, hydrogen peroxide production, superparamagnetic

  20. Cell Wall Amine Oxidases: New Players in Root Xylem Differentiation under Stress Conditions.

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    Ghuge, Sandip A; Tisi, Alessandra; Carucci, Andrea; Rodrigues-Pousada, Renato A; Franchi, Stefano; Tavladoraki, Paraskevi; Angelini, Riccardo; Cona, Alessandra

    2015-07-14

    Polyamines (PAs) are aliphatic polycations present in all living organisms. A growing body of evidence reveals their involvement as regulators in a variety of physiological and pathological events. They are oxidatively deaminated by amine oxidases (AOs), including copper amine oxidases (CuAOs) and flavin adenine dinucleotide (FAD)-dependent polyamine oxidases (PAOs). The biologically-active hydrogen peroxide (H₂O₂) is a shared compound in all of the AO-catalyzed reactions, and it has been reported to play important roles in PA-mediated developmental and stress-induced processes. In particular, the AO-driven H₂O₂ biosynthesis in the cell wall is well known to be involved in plant wound healing and pathogen attack responses by both triggering peroxidase-mediated wall-stiffening events and signaling modulation of defense gene expression. Extensive investigation by a variety of methodological approaches revealed high levels of expression of cell wall-localized AOs in root xylem tissues and vascular parenchyma of different plant species. Here, the recent progresses in understanding the role of cell wall-localized AOs as mediators of root xylem differentiation during development and/or under stress conditions are reviewed. A number of experimental pieces of evidence supports the involvement of apoplastic H₂O₂ derived from PA oxidation in xylem tissue maturation under stress-simulated conditions.

  1. Cell Wall Amine Oxidases: New Players in Root Xylem Differentiation under Stress Conditions

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    Sandip A. Ghuge

    2015-07-01

    Full Text Available Polyamines (PAs are aliphatic polycations present in all living organisms. A growing body of evidence reveals their involvement as regulators in a variety of physiological and pathological events. They are oxidatively deaminated by amine oxidases (AOs, including copper amine oxidases (CuAOs and flavin adenine dinucleotide (FAD-dependent polyamine oxidases (PAOs. The biologically-active hydrogen peroxide (H2O2 is a shared compound in all of the AO-catalyzed reactions, and it has been reported to play important roles in PA-mediated developmental and stress-induced processes. In particular, the AO-driven H2O2 biosynthesis in the cell wall is well known to be involved in plant wound healing and pathogen attack responses by both triggering peroxidase-mediated wall-stiffening events and signaling modulation of defense gene expression. Extensive investigation by a variety of methodological approaches revealed high levels of expression of cell wall-localized AOs in root xylem tissues and vascular parenchyma of different plant species. Here, the recent progresses in understanding the role of cell wall-localized AOs as mediators of root xylem differentiation during development and/or under stress conditions are reviewed. A number of experimental pieces of evidence supports the involvement of apoplastic H2O2 derived from PA oxidation in xylem tissue maturation under stress-simulated conditions.

  2. Nanoparticle strategies for cancer therapeutics: Nucleic acids, polyamines, bovine serum amine oxidase and iron oxide nanoparticles (Review).

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    Agostinelli, Enzo; Vianello, Fabio; Magliulo, Giuseppe; Thomas, Thresia; Thomas, T J

    2015-01-01

    Nanotechnology for cancer gene therapy is an emerging field. Nucleic acids, polyamine analogues and cytotoxic products of polyamine oxidation, generated in situ by an enzyme-catalyzed reaction, can be developed for nanotechnology-based cancer therapeutics with reduced systemic toxicity and improved therapeutic efficacy. Nucleic acid-based gene therapy approaches depend on the compaction of DNA/RNA to nanoparticles and polyamine analogues are excellent agents for the condensation of nucleic acids to nanoparticles. Polyamines and amine oxidases are found in higher levels in tumours compared to that of normal tissues. Therefore, the metabolism of polyamines spermidine and spermine, and their diamine precursor, putrescine, can be targets for antineoplastic therapy since these naturally occurring alkylamines are essential for normal mammalian cell growth. Intracellular polyamine concentrations are maintained at a cell type-specific set point through the coordinated and highly regulated interplay between biosynthesis, transport, and catabolism. In particular, polyamine catabolism involves copper-containing amine oxidases. Several studies showed an important role of these enzymes in developmental and disease-related processes in animals through the control of polyamine homeostasis in response to normal cellular signals, drug treatment, and environmental and/or cellular stress. The production of toxic aldehydes and reactive oxygen species (ROS), H2O2 in particular, by these oxidases suggests a mechanism by which amine oxidases can be exploited as antineoplastic drug targets. The combination of bovine serum amine oxidase (BSAO) and polyamines prevents tumour growth, particularly well if the enzyme has been conjugated with a biocompatible hydrogel polymer. The findings described herein suggest that enzymatically formed cytotoxic agents activate stress signal transduction pathways, leading to apoptotic cell death. Consequently, superparamagnetic nanoparticles or other

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

    OpenAIRE

    2004-01-01

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

  4. Syncephalastrum racemosum amine oxidase with high catalytic efficiency toward ethanolamine and its application in ethanolamine determination.

    Science.gov (United States)

    Hirano, Yoshitaka; Chonan, Keisuke; Murayama, Kazutaka; Sakasegawa, Shin-Ich; Matsumoto, Hideyuki; Sugimori, Daisuke

    2016-05-01

    Our screening study yielded a copper amine oxidase (SrAOX) from Syncephalastrum racemosum, which showed much higher affinity and catalytic efficiency toward ethanolamine (EA) than any other amine oxidase (AOX). Following purification of the enzyme to electrophoretic homogeneity from a cell-free extract, the maximum activity toward EA was detected at pH 7.2-7.5 and 45 °C. The SrAOX complementary DNA (cDNA) was composed of a 2052-bp open reading frame encoding a 683-amino acid protein with a molecular mass of 77,162 Da. The enzyme functions as a homodimer. The deduced amino acid sequence of SrAOX showed 55.3 % identity to Rhizopus delemar AOX and contains two consensus sequences of Cu-AOX, NYDY, and HHQH, suggesting SrAOX is a type 1 Cu-AOX (i.e., a topaquinone enzyme). Structural homology modeling showed that residues (112)ML(113), (141)FADTWG(146) M158, and N318 are unique, and T144 possibly characterizes the substrate specificity of SrAOX. The recombinant enzyme (rSrAOX) was produced using Escherichia coli. Steady-state kinetic analysis of rSrAOX activity toward EA (pH 7.5 and 45 °C) gave K m and k cat values of 0.848 ± 0.009 mM and 9.11 ± 0.13 s(-1), respectively. The standard curves were linear between 0.1 and 2 mM EA, and 10 μg mL(-1)-2.5 mg mL(-1) (15 μM-3.6 mM) phosphatidylethanolamine using Streptomyces chromofuscus phospholipase D, respectively, was sufficiently sensitive for clinical use.

  5. Copper complexes as biomimetic models of catechol oxidase : mechanistic studies

    NARCIS (Netherlands)

    Koval, Iryna A.

    2006-01-01

    The research described in this thesis deals with the synthesis of copper(II) complexes with phenol-based or macrocyclic ligands, which can be regarded as model compounds of the active site of catechol oxidase, and with the mechanism of the catalytic oxidation of catechol mediated by these compounds.

  6. The N-terminus of amine oxidase of Hansenula polymorpha contains a peroxisomal targeting signal

    NARCIS (Netherlands)

    Faber, Klaas Nico; Keizer-Gunnink, Ineke; Pluim, Dick; Harder, Willem; AB, Geert; Veenhuis, Marten

    1995-01-01

    Here we describe the identification of the targeting sequence of peroxisomal amine oxidase (AMO) of H. polymorpha. Deletion analysis revealed that essential targeting information is located within the extreme N-terminal 16 amino acids. Moreover, this sequence can direct a reporter protein to the per

  7. Plasma semicarbazide-sensitive amine oxidase (SSAO) is an independent prognostic marker for mortality in chronic heart failure

    NARCIS (Netherlands)

    Boomsma, F; De Kam, PJ; Van Den Meiracker, AH; Van Veldhuisen, DJ

    2000-01-01

    Aims Experimental evidence has suggested that semicarbazide-sensitive amine oxidase is involved in vascular endothelial damage and in the process of atherosclerosis, through the formation of reactive aldehydes, hydrogen peroxide and ammonia from endogenous substrates. Recent evidence indicates that

  8. Structural and functional mimic of galactose oxidase by a copper complex of a sterically demanding [N2O2] ligand.

    Science.gov (United States)

    John, Alex; Shaikh, Mobin M; Ghosh, Prasenjit

    2008-06-07

    A structural and functional mimic of the galactose oxidase (GOase) enzyme active-site by a copper complex supported over a sterically demanding ligand having [N2O2] donor sites is reported. Specifically, the binding of the histidine (496 and 581) and tyrosine (272 and 495) residues to the copper center in a square-pyramidal fashion in the active-site of galactose oxidase (GOase) enzyme has been modeled in a copper complex, ([(3-tert-butyl-5-methyl-2-hydoxybenzyl)(3'-tert-butyl-5'-methyl-2'-oxobenzyl)(2-pyridylmethyl)]amine)Cu(OAc)) (1b), stabilized over a sterically demanding ligand in which the two phenolate-O atoms mimicked the tyrosine binding while an amine-N and pyridyl-N atoms emulated the histidine binding to the metal center, similar to that in the enzyme active-site. Furthermore, the copper complex 1b is found to be an effective functional model of the enzyme as it efficiently catalyzed the chemoselective oxidation of primary alcohols to aldehydes in high turnover numbers under ambient conditions. An insight into the nature of the active-species was obtained by EPR and CV studies, which in conjunction with the DFT studies, revealed that the active-species is an anti-ferromagnetically coupled diamagnetic radical cation, (1)1b+, obtained by one electron oxidation at the equatorial phenolate-O atom of the ligand in the 1b complex.

  9. From caffeine to fish waste: amine compounds present in food and drugs and their interactions with primary amine oxidase.

    LENUS (Irish Health Repository)

    Olivieri, Aldo

    2011-07-01

    Tissue bound primary amine oxidase (PrAO) and its circulating plasma-soluble form are involved, through their catalytic activity, in important cellular roles, including the adhesion of lymphocytes to endothelial cells during various inflammatory conditions, the regulation of cell growth and maturation, extracellular matrix deposition and maturation and glucose transport. PrAO catalyses the oxidative deamination of several xenobiotics and has been linked to vascular toxicity, due to the generation of cytotoxic aldehydes. In this study, a series of amines and aldehydes contained in food and drugs were tested via a high-throughput assay as potential substrates or inhibitors of bovine plasma PrAO. Although none of the compounds analyzed were found to be substrates for the enzyme, a series of molecules, including caffeine, the antidiabetics phenformin and tolbutamide and the antimicrobial pentamidine, were identified as PrAO inhibitors. Although the inhibition observed was in the millimolar and micromolar range, these data show that further work will be necessary to elucidate whether the interaction of ingested biogenic or xenobiotic amines with PrAO might adversely affect its biological roles.

  10. PEROXISOMAL AMINE OXIDASE OF HANSENULA-POLYMORPHA DOES NOT REQUIRE ITS SRL-CONTAINING C-TERMINAL SEQUENCE FOR TARGETING

    NARCIS (Netherlands)

    FABER, KN; HAIMA, P; DEHOOP, MJ; HARDER, W; VEENHUIS, M; AB, G

    1993-01-01

    Amine oxidase (AMO) is a peroxisomal matrix protein of Hansenula polymorpha, which is induced during growth of the yeast in media containing primary amines as a sole nitrogen source. The deduced amino acid sequence of the protein contains an SRL sequence at nine amino acids from the C-terminus. In t

  11. Characterization of the in vitro binding and inhibition kinetics of primary amine oxidase/vascular adhesion protein-1 by glucosamine.

    LENUS (Irish Health Repository)

    Olivieri, Aldo

    2012-04-01

    Primary-amine oxidase (PrAO) catalyzes the oxidative deamination of endogenous and exogenous primary amines and also functions, in some tissues, as an inflammation-inducible endothelial factor, known as vascular adhesion protein-1. VAP-1 mediates the slow rolling and adhesion of lymphocytes to endothelial cells in a number of inflammatory conditions, including inflammation of the synovium.

  12. Copper(II)-catalyzed electrophilic amination of quinoline N-oxides with O-benzoyl hydroxylamines.

    Science.gov (United States)

    Li, Gang; Jia, Chunqi; Sun, Kai; Lv, Yunhe; Zhao, Feng; Zhou, Kexiao; Wu, Hankui

    2015-03-21

    Copper acetate-catalyzed C-H bond functionalization amination of quinoline N-oxides was achieved using O-benzoyl hydroxylamine as an electrophilic amination reagent, thereby affording the desired products in moderate to excellent yields. Electrophilic amination can also be performed in good yield on a gram scale.

  13. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... substances identified generically as copper complex of (substituted sulfonaphthyl azo substituted...

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

    NARCIS (Netherlands)

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

    1981-01-01

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

  15. Engineering an enantioselective amine oxidase for the synthesis of pharmaceutical building blocks and alkaloid natural products.

    Science.gov (United States)

    Ghislieri, Diego; Green, Anthony P; Pontini, Marta; Willies, Simon C; Rowles, Ian; Frank, Annika; Grogan, Gideon; Turner, Nicholas J

    2013-07-24

    The development of cost-effective and sustainable catalytic methods for the production of enantiomerically pure chiral amines is a key challenge facing the pharmaceutical and fine chemical industries. This challenge is highlighted by the estimate that 40-45% of drug candidates contain a chiral amine, fueling a demand for broadly applicable synthetic methods that deliver target structures in high yield and enantiomeric excess. Herein we describe the development and application of a "toolbox" of monoamine oxidase variants from Aspergillus niger (MAO-N) which display remarkable substrate scope and tolerance for sterically demanding motifs, including a new variant, which exhibits high activity and enantioselectivity toward substrates containing the aminodiphenylmethane (benzhydrylamine) template. By combining rational structure-guided engineering with high-throughput screening, it has been possible to expand the substrate scope of MAO-N to accommodate amine substrates containing bulky aryl substituents. These engineered MAO-N biocatalysts have been applied in deracemization reactions for the efficient asymmetric synthesis of the generic active pharmaceutical ingredients Solifenacin and Levocetirizine as well as the natural products (R)-coniine, (R)-eleagnine, and (R)-leptaflorine. We also report a novel MAO-N mediated asymmetric oxidative Pictet-Spengler approach to the synthesis of (R)-harmicine.

  16. 2-bromoethylamine, a suicide inhibitor of semicarbazide-sensitive amine oxidase, increases hydralazine hypotension in rats.

    Science.gov (United States)

    Vidrio, Horacio; Medina, Martha

    2005-09-01

    Previous work has shown that inhibitors of the predominantly vascular enzyme semicarbazide-sensitive amine oxidase (SSAO) potentiate the hypotensive response to hydralazine, itself a SSAO inhibitor, in anesthetized rats. The present study was carried out to determine whether the recently described suicide SSAO inhibitor 2-bromoethylamine shares this effect. Hypotensive responses to hydralazine, 0.1 mg/kg IV, were obtained in chloralose-urethane-anesthetized rats, either unpretreated or receiving bromoethylamine at different doses and pretreatment intervals. Parallel experiments were run with semicarbazide, the prototypical hydrazine SSAO inhibitor. Both inhibitors potentiated hydralazine hypotension, bromoethylamine having a longer latency and a shorter duration of action than semicarbazide. High doses of bromoethylamine did not produce potentiation, a phenomenon attributed to SSAO inactivation by excess substrate and decreased formation by the enzyme of the inhibitor product. Experiments with combined administration of both inhibitors were also carried out. When semicarbazide was administered before bromoethylamine, potentiaton was prevented, apparently by a mechanism similar to the above; when it was given after the amine, potentiation was increased. This was attributed to enzyme inhibition by interaction with 2 different active sites. The charactertistics of hydralazine potentiation by bromoethylamine were considered compatible with the mechanism of SSAO inhibition by the amine.

  17. N-heterocyclic carbene copper(I) catalysed N-methylation of amines using CO2

    KAUST Repository

    Santoro, Orlando

    2015-09-30

    The N-methylation of amines using CO2 and PhSiH3 as source of CH3 was efficiently performed using a N-heterocyclic carbene copper(I) complex. The methodology was found compatible with aromatic and aliphatic primary and secondary amines. Synthetic and computational studies have been carried out to support the proposed reaction mechanism for this transformation.

  18. Azide binding to the trinuclear copper center in laccase and ascorbate oxidase

    DEFF Research Database (Denmark)

    Gromov, I; Marchesini, A; Farver, O

    1999-01-01

    Azide binding to the blue copper oxidases laccase and ascorbate oxidase (AO) was investigated by electron paramagnetic resonance (EPR) and pulsed electron-nuclear double resonance (ENDOR) spectroscopies. As the laccase : azide molar ratio decreases from 1:1 to 1:7, the intensity of the type 2 (T2...

  19. Interstitial renal fibrosis due to multiple cisplatin treatments is ameliorated by semicarbazide-sensitive amine oxidase inhibition.

    Science.gov (United States)

    Katagiri, Daisuke; Hamasaki, Yoshifumi; Doi, Kent; Negishi, Kousuke; Sugaya, Takeshi; Nangaku, Masaomi; Noiri, Eisei

    2016-02-01

    Elucidation of acute kidney diseases and disorders (AKD), including acute kidney injury (AKI), is important to prevent their progression to chronic kidney disease. Current animal AKI models are often too severe for use in evaluating human AKI. Therefore, new animal models of mild kidney injury are needed. Here a new clinically relevant animal model using multiple low doses of cisplatin (CP) was used to evaluate AKD. When 10 mg/kg CP was administered intraperitoneally once weekly for three times to L-type fatty acid-binding protein (L-FABP) transgenic mice, moderate renal interstitial fibrosis and tubule dilatation occurred, accompanied by brush-border loss. Urinary L-FABP, a promising biomarker of AKI, changed more drastically than blood urea nitrogen or creatinine. Preventing fibrosis in organs was also studied. Oral administration of a recently reported selective semicarbazide-sensitive amine oxidase inhibitor, PXS-4728A, for 1 week attenuated kidney injury and interstitial fibrosis compared with vehicle. Inhibition of renal lipid accumulation in semicarbazide-sensitive amine oxidase inhibitor-treated mice, together with reduced oxidative stress and L-FABP suppression in proximal tubules, suggested an antifibrotic effect of semicarbazide-sensitive amine oxidase inhibition in this CP-AKD model, a representative onco-nephrology. Thus, semicarbazide-sensitive amine oxidase inhibitors may be promising candidates for the prevention of chronic kidney disease in patients using CP to treat malignancy.

  20. Semicarbazide-sensitive amine oxidase: role in the vasculature and vasodilation after in situ inhibition.

    Science.gov (United States)

    Vidrio, H

    2003-01-01

    1. The characteristics of semicarbazide-sensitive amine oxidase (SSAO) are reviewed and the unknown physiological or pathological role of this enzyme emphasized. 2. The various mechanisms of action proposed for the vasodilator drug hydralazine are considered. In particular, the inhibitory action on various enzymes, related or not to cardiovascular function, are discussed. 3. Studies linking inhibition of SSAO to hydralazine hypotension are reviewed and a general hypothesis relating both actions is presented. The hypothesis postulates that (a). vascular SSAO is involved in the regulation of vascular tone, and (b). hydralazine vasodilation is the consequence of vascular SSAO inhibition. 4. Evidence supporting these postulates is presented and vascular SSAO inhibition is proposed as a novel mechanism of vasodilation.

  1. Applying of copper(ІІ carbonate as a decrease mode of a fire hazard of epoxy-amine composites

    Directory of Open Access Journals (Sweden)

    Олена Іванівна Лавренюк

    2016-05-01

    Full Text Available Being based on data about electronic and crystal structure of copper salts, their using perspective for fire retardants of epoxy-amine composites have been foreseen. Epoxy-amine composites modified by copper compounds, in particular, by copper(ІІ carbonate have been elaborated. Influence of fire retardant onto processes of thermal-oxidative decomposition of epoxy-amine composites and their fire hazard has been studied

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

    Science.gov (United States)

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

    2016-05-01

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

  3. Construction and characterization of an azurin analog for the purple copper site in cytochrome c oxidase.

    OpenAIRE

    Hay, M; Richards, J. H.; Lu, Y.

    1996-01-01

    A protein analog of a purple copper center has been constructed from a recombinant blue copper protein (Pseudomonas aeruginosa azurin) by replacing the loop containing the three ligands to the blue copper center with the corresponding loop of the CuA center in cytochrome c oxidase (COX) from Paracoccus denitrificans. The electronic absorption in the UV and visible region (UV-vis) and electron paramagnetic resonance (EPR) spectra of this analog are remarkably similar to those of the native CuA...

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

    Science.gov (United States)

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

    2015-04-29

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

  5. Semicarbazide-sensitive amine oxidase substrates potentiate hydralazine hypotension: possible role of hydrogen peroxide.

    Science.gov (United States)

    Vidrio, Horacio; Medina, Martha; González-Romo, Pilar; Lorenzana-Jiménez, Marte; Díaz-Arista, Patricia; Baeza, Alejandro

    2003-11-01

    The relation between inhibition of semicarbazide-sensitive amine oxidase (SSAO) and vasodilation by hydralazine (HYD) was evaluated in chloralose/urethane-anesthetized rats pretreated with various substrates of the enzyme and subsequently administered a threshold hypotensive dose of the vasodilator. The SSAO substrates benzylamine, phenethylamine, and methylamine potentiate the hypotensive response to HYD. Methylamine, which was studied in greater detail because of its status as a possible endogenous SSAO substrate, does not influence the response to the reference vasodilator pinacidil; it does enhance HYD relaxation in aortic rings obtained from pretreated rats. Experiments designed to identify the product of SSAO activity responsible for potentiation by methylamine suggest involvement of hydrogen peroxide (H2O2), as evidenced by the findings that such potentiation is abolished by additional pretreatment with the H2O2-metabolizing enzyme catalase, and that the plasma concentration of H2O2 is increased by methylamine and decreased by HYD. These results are interpreted as a substantiation of the relation between the known SSAO inhibitory effect of HYD and its vasodilator activity. Pretreatment with the SSAO substrates would increase production of H2O2 in vascular smooth muscle and thus magnify the influence of this vasoconstrictor agent on vascular tone. In these conditions, the decrease in H2O2 production and hence in vascular tone caused by SSAO inhibition by HYD would also be magnified. It is speculated that inhibition of vascular SSAO could represent a novel mechanism of vasodilation.

  6. Interaction of L-lysine and soluble elastin with the semicarbazide-sensitive amine oxidase in the context of its vascular-adhesion and tissue maturation functions.

    LENUS (Irish Health Repository)

    Olivieri, Aldo

    2010-04-01

    The copper-containing quinoenzyme semicarbazide-sensitive amine oxidase (EC 1.4.3.21; SSAO) is a multifunctional protein. In some tissues, such as the endothelium, it also acts as vascular-adhesion protein 1 (VAP-1), which is involved in inflammatory responses and in the chemotaxis of leukocytes. Earlier work had suggested that lysine might function as a recognition molecule for SSAO\\/VAP-1. The present work reports the kinetics of the interaction of L-lysine and some of its derivatives with SSAO. Binding was shown to be saturable, time-dependent but reversible and to cause uncompetitive inhibition with respect to the amine substrate. It was also specific, since D-lysine, L-lysine ethyl ester and epsilon-acetyl-L-lysine, for example, did not bind to the enzyme. The lysine-rich protein soluble elastin bound to the enzyme relatively tightly, which may have relevance to the reported roles of SSAO in maintaining the extracellular matrix (ECM) and in the maturation of elastin. Our data show that lysyl residues are not oxidized by SSAO, but they bind tightly to the enzyme in the presence of hydrogen peroxide. This suggests that binding in vivo of SSAO to lysyl residues in physiological targets might be regulated in the presence of H(2)O(2), formed during the oxidation of a physiological SSAO substrate, yet to be identified.

  7. Aminoarenethiolate-Copper(I)-Catalyzed Amination of Aryl Bromides

    NARCIS (Netherlands)

    Jerphagnon, Thomas; Klink, Gerard P.M. van; Vries, Johannes G. de; Koten, Gerard van

    2005-01-01

    Aminoarenethiolate-copper(I) complexes are known to be efficient catalysts for carbon-carbon bond formation. Here, we show the first examples that these thiolate-copper(I) complexes are efficient for carbon-nitrogen bond formation reactions as well. N-Arylation of benzylamine and imidazole with

  8. Aminoarenethiolate-Copper(I)-Catalyzed Amination of Aryl Bromides

    NARCIS (Netherlands)

    Jerphagnon, Thomas; Klink, Gerard P.M. van; Vries, Johannes G. de; Koten, Gerard van

    2005-01-01

    Aminoarenethiolate-copper(I) complexes are known to be efficient catalysts for carbon-carbon bond formation. Here, we show the first examples that these thiolate-copper(I) complexes are efficient for carbon-nitrogen bond formation reactions as well. N-Arylation of benzylamine and imidazole with brom

  9. Copper and amine free Sonogashira cross-coupling reaction catalyzed by efficient diphosphane-palladium catalyst

    Institute of Scientific and Technical Information of China (English)

    Ting He; Lei Lei Wu; Xing Li Fu; Hai Yan Fu; Hua Chen; Rui Xiang Li

    2011-01-01

    The commercially available diphosphane ligand MeO-BIPHEP was first investigated in the palladium-catalyzed Sonogashira reaction in the absence of copper and amine. The coupling of various aryl bromides and aryl chlorides with phenylacetylene gave moderate to excellent yields.

  10. Copper-mediated pyrazole synthesis from 2,3-allenoates or 2-alkynoates, amines and nitriles.

    Science.gov (United States)

    Chen, Bo; Zhu, Can; Tang, Yang; Ma, Shengming

    2014-07-21

    An efficient copper-mediated three-component reaction of 2,3-allenoates or 2-alkynoates, amines, and nitriles affording fully substituted pyrazoles with a very nice diversity has been developed. A tandem conjugate addition, 1,2-addition, and N-N bond formation mechanism has been proposed for this diverse synthesis of pyrazoles based on mechanistic studies.

  11. Immobilization of Magnetic Nanoparticles onto Amine-Modified Nano-Silica Gel for Copper Ions Remediation

    Directory of Open Access Journals (Sweden)

    Marwa Elkady

    2016-06-01

    Full Text Available A novel nano-hybrid was synthesized through immobilization of amine-functionalized silica gel nanoparticles with nanomagnetite via a co-precipitation technique. The parameters, such as reagent concentrations, reaction temperature and time, were optimized to accomplish the nano-silica gel chelating matrix. The most proper amine-modified silica gel nanoparticles were immobilized with magnetic nanoparticles. The synthesized magnetic amine nano-silica gel (MANSG was established and characterized using X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, Fourier transform infrared (FTIR, thermal gravimetric analysis (TGA, differential scanning calorimetry (DSC and vibrating sample magnetometry (VSM. The feasibility of MANSG for copper ions’ remediation from wastewater was examined. MANSG achieves a 98% copper decontamination from polluted water within 90 min. Equilibrium sorption of copper ions onto MANSG nanoparticles obeyed the Langmuir equation compared to the Freundlich, Temkin, Elovich and Dubinin-Radushkevich (D-R equilibrium isotherm models. The pseudo-second-order rate kinetics is appropriate to describe the copper sorption process onto the fabricated MANSG.

  12. Mechanism study of copper-mediated one-pot reductive amination of aryl halides using trimethylsilyl azide.

    Science.gov (United States)

    Maejima, Toshihide; Ueda, Moriatsu; Nakano, Jun; Sawama, Yoshinari; Monguchi, Yasunari; Sajiki, Hironao

    2013-09-20

    Reaction mechanisms of the copper-mediated amination of aryl halides with trimethylsilyl azide (TMSN3) were analyzed on the basis of the time-course study using reaction monitoring FT-IR, trapping an intermediary aryl azide by the Huisgen reaction, and the analysis of the generated N2 gas during the reaction. This amination would proceed through multiple pathways via aryl radicals and copper(I) azide.

  13. amines

    Directory of Open Access Journals (Sweden)

    Styszko Katarzyna

    2017-01-01

    Full Text Available The study investigated the application of char activated with CO2 and impregnated with amines solutions for removal of selected xenobiotics from aqueous solutions. The chars produced from the pyrolysis of waste tires. The solutions of monoethanolamine (MEA, diethanolamine (DEA and polyethylenimine (PEI were used for impregnation of char. The sorption capacity of char impregnated with amines depended on amines chemical properties. The adsorptive removal of mixture of pharmaceuticals residues by modified materials was assessed. BET surface area of materials varied from 36 m2 g−1 to 128 m2 g−1. The highest removal efficiencies up to 99 % were observed for char impregnated with PEI.

  14. Construction and characterization of an azurin analog for the purple copper site in cytochrome c oxidase.

    Science.gov (United States)

    Hay, M; Richards, J H; Lu, Y

    1996-01-09

    A protein analog of a purple copper center has been constructed from a recombinant blue copper protein (Pseudomonas aeruginosa azurin) by replacing the loop containing the three ligands to the blue copper center with the corresponding loop of the CuA center in cytochrome c oxidase (COX) from Paracoccus denitrificans. The electronic absorption in the UV and visible region (UV-vis) and electron paramagnetic resonance (EPR) spectra of this analog are remarkably similar to those of the native CuA center in COX from Paracoccus denitrificans. The above spectra can be obtained upon addition of a mixture of Cu2+ and Cu+. Addition of Cu2+ only results in a UV-vis spectrum consisting of absorptions from both a purple copper center and a blue copper center. This spectrum can be converted to the spectrum of a pure purple copper by a prolonged incubation in the air, or by addition of excess ascorbate. The azurin mutant reported here is an example of an engineered purple copper center with the A480/A530 ratio greater than 1 and with no detectable hyperfines, similar to those of the CuA sites in COX of bovine heart and of Paracoccus denitrificans.

  15. Mono-nuclear copper complexes mimicking the intermediates for the binuclear copper center of the subunit II of cytochrome oxidase: a peptide based approach.

    Science.gov (United States)

    Dutta Gupta, Dwaipayan; Usharani, Dandamudi; Mazumdar, Shyamalava

    2016-11-28

    Three stable copper complexes of peptides derived from the copper ion binding loop of the subunit II of cytochrome c oxidase have been prepared and characterized by various spectroscopic techniques. These stable copper complexes of peptides were found to exhibit cysteine, histidine and/or methionine ligation, which has predominant σ-contribution in the Cys-Cu charge transfer. The copper(ii) peptide complexes showed type-2 EPR spectra, which is uncommon in copper-cysteinate complexes. UV-visible spectra, Raman and EPR results support a tetragonal structure of the coordination geometry around the copper ion. The copper complex of the 9-amino acid peptide suggested the formation of a 'red' copper center while the copper complexes of the 12- and 11-amino acid peptides showed the formation of a 'green' copper center. The results provide insights on the first stable models of the copper complexes formed in the peptide scaffold that mimic the mono-nuclear copper bound protein intermediates proposed during the formation of the binuclear Cu2S2 core of the enzyme. These three copper complexes of peptides derived from the metal ion binding loop of the CuA center of the subunit II of cytochrome c oxidase showed novel spectroscopic properties which have not so far been reported in any stable small complex.

  16. Microwave-assisted chemoselective copper-catalyzed amination of o-chloro and o-bromobenzoic acids using aromatic amines under solvent free conditions

    Institute of Scientific and Technical Information of China (English)

    Yaghoub Sarrafi; Manijeh Mohadeszadeh; Kamal Alimohammadi

    2009-01-01

    Copper-catalyzed synthesis of N-aryl anthranilic acid derivatives using effective amination of 2-chloro and 2-bromobenzoic acid under microwave irradiation is reported. Some of the advantages of this method axe high chemoselectivity, short reaction times, ease of work up procedure and elimination of the need for acid protection.

  17. Dinuclear copper complexes with imidazole derivative ligands: a theoretical study related to catechol oxidase activity.

    Science.gov (United States)

    Martínez, Ana; Membrillo, Ingrid; Ugalde-Saldívar, Victor M; Gasque, Laura

    2012-07-19

    Catechol oxidase is a very important and interesting metalloprotein. In spite of the efforts to understand the reaction mechanism of this protein, there are important questions that remain unanswered concerning the catalytic mechanism of this enzyme. In this article, dinuclear copper compounds are used as biomimetic models of catechol oxidase to study plausible reaction paths. These dinuclear copper(II) complexes have distant metal centers (of 7.5 Å approximately) and superior catalytic activity to that of many dicopper complexes with shorter Cu-Cu distances. One mononuclear copper(II) complex is also analyzed in this investigation in order to see the influence of the two metal centers in the catalytic activity. Density functional theory calculations were performed to obtain optimized structures, vertical ionization energies, vertical electron affinities, the electrodonating power (ω(-)), the electroaccepting power (ω(+)) and the energy difference of several reaction paths. The K(M) experimental results that were previously reported compare well with the electroaccepting power (ω(+)) of the copper compounds that are included in this article, indicating that this index is useful for the interpretation of the electron transfer capacity and therefore the catalytic activity. The catechol moiety coordinates to only one Cu ion, but two metal atoms are needed in order to have a good electron acceptor capacity of the biomimetic models.

  18. Plasma semicarbazide-sensitive amine oxidase is moderately decreased by pronounced exogenous hyperinsulinemia but is not associated with insulin sensitivity and body fat

    NARCIS (Netherlands)

    Dullaart, R. P. F.; Riemens, S. C.; Boomsma, F.

    2006-01-01

    Objective. Semicarbazide-sensitive amine oxidase (SSAO) is widely expressed in adipose tissue, where it may contribute to stimulation of glucose transport via GLUT4 recruitment. We tested the relationships of soluble SSAO, as reflected by its plasma activity, with insulin sensitivity and indices of

  19. In Absence of the Cellular Prion Protein, Alterations in Copper Metabolism and Copper-Dependent Oxidase Activity Affect Iron Distribution

    Science.gov (United States)

    Gasperini, Lisa; Meneghetti, Elisa; Legname, Giuseppe; Benetti, Federico

    2016-01-01

    Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defined mechanisms. Prion protein, for instance, interacts with divalent cations via multiple metal-binding sites and it modulates several metal-dependent physiological functions, such as S-nitrosylation of NMDA receptors. In this work we focused on the effect of prion protein absence on copper and iron metabolism during development and adulthood. In particular, we investigated copper and iron functional values in serum and several organs such as liver, spleen, total brain and isolated hippocampus. Our results show that iron content is diminished in prion protein-null mouse serum, while it accumulates in liver and spleen. Our data suggest that these alterations can be due to impairments in copper-dependent cerulopalsmin activity which is known to affect iron mobilization. In prion protein-null mouse total brain and hippocampus, metal ion content shows a fluctuating trend, suggesting the presence of homeostatic compensatory mechanisms. However, copper and iron functional values are likely altered also in these two organs, as indicated by the modulation of metal-binding protein expression levels. Altogether, these results reveal that the absence of the cellular prion protein impairs copper metabolism and copper-dependent oxidase activity, with ensuing alteration of iron mobilization from cellular storage compartments. PMID:27729845

  20. In Absence of the Cellular Prion Protein, Alterations in Copper Metabolism and Copper-Dependent Oxidase Activity Affect Iron Distribution.

    Science.gov (United States)

    Gasperini, Lisa; Meneghetti, Elisa; Legname, Giuseppe; Benetti, Federico

    2016-01-01

    Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defined mechanisms. Prion protein, for instance, interacts with divalent cations via multiple metal-binding sites and it modulates several metal-dependent physiological functions, such as S-nitrosylation of NMDA receptors. In this work we focused on the effect of prion protein absence on copper and iron metabolism during development and adulthood. In particular, we investigated copper and iron functional values in serum and several organs such as liver, spleen, total brain and isolated hippocampus. Our results show that iron content is diminished in prion protein-null mouse serum, while it accumulates in liver and spleen. Our data suggest that these alterations can be due to impairments in copper-dependent cerulopalsmin activity which is known to affect iron mobilization. In prion protein-null mouse total brain and hippocampus, metal ion content shows a fluctuating trend, suggesting the presence of homeostatic compensatory mechanisms. However, copper and iron functional values are likely altered also in these two organs, as indicated by the modulation of metal-binding protein expression levels. Altogether, these results reveal that the absence of the cellular prion protein impairs copper metabolism and copper-dependent oxidase activity, with ensuing alteration of iron mobilization from cellular storage compartments.

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

    Science.gov (United States)

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

    1983-05-01

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

  2. Spectroscopic studies of copper enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, D.M.; Moog, R.; Zumft, W.; Koenig, S.H.; Scott, R.A.; Cote, C.E.; McGuirl, M.

    1986-05-01

    Several spectroscopic methods, including absorption, circular dichroism (CD), magnetic CD (MCD), X-ray absorption, resonance Raman, EPR, NMR, and quasi-elastic light-scattering spectroscopy, have been used to probe the structures of copper-containing amine oxidases, nitrite reductase, and nitrous oxide reductase. The basic goals are to determine the copper site structure, electronic properties, and to generate structure-reactivity correlations. Collectively, the results on the amine oxidases permit a detailed model for the Cu(II) sites in these enzymes to be constructed that, in turn, rationalizes the ligand-binding chemistry. Resonance Raman spectra of the phenylhydrazine and 2,4-dinitrophenyl-hydrazine derivatives of bovine plasma amine oxidase and models for its organic cofactor, e.g. pyridoxal, methoxatin, are most consistent with methoxatin being the intrinsic cofactor. The structure of the Cu(I) forms of the amine oxidases have been investigated by X-ray absorption spectroscopy (XAS); the copper coordination geometry is significantly different in the oxidized and reduced forms. Some anomalous properties of the amine oxidases in solution are explicable in terms of their reversible aggregation, which the authors have characterized via light scattering. Nitrite and nitrous oxide reductases display several novel spectral properties. The data suggest that new types of copper sites are present.

  3. Bioconjugation of gold-polymer core-shell nanoparticles with bovine serum amine oxidase for biomedical applications.

    Science.gov (United States)

    Venditti, I; Hassanein, T F; Fratoddi, I; Fontana, L; Battocchio, C; Rinaldi, F; Carafa, M; Marianecci, C; Diociaiuti, M; Agostinelli, E; Cametti, C; Russo, M V

    2015-10-01

    Core-shell gold nanoparticles [AuNPs], stabilized with a hydrophilic polymer, poly(3-dimethylammonium-1-propyne hydrochloride) [PDMPAHCl], have been used for the immobilization of bovine serum amine oxidase [BSAO]. The functionalized surface of the hybrid nanoparticles is pH responsive, due to the presence of aminic groups that carry out a double role: on one hand they act as ligands for the gold nanoparticle surface, allowing the colloidal stabilization and, on the other hand, they give a hydrophilic characteristic to the whole colloidal suspension. The core-shell nanoparticles [Au@PDMPAHCl] have been characterized by using UV-vis and X-ray photoelectron spectroscopy, DLS, ζ-potential measurements and by FE-TEM microscopy. BSAO enzyme can be loaded by non-covalent immobilization onto Au@PDMPAHCl nanoparticles up to 70% in weight, depending on the pH values of the environmental medium. Activity tests on Au@PDMPAHCl-BSAO bioconjugates confirm an enzymatic activity up to 40%, with respect to the free enzyme activity. Moreover, our results show that loading and enzymatic activity are rather interrelated characteristics and that, under appropriate polymer concentration and pH conditions, a satisfactory compromise can be reached. These results, as a whole, indicate that Au@PDMPAHCl-BSAO bioconjugate systems are promising for future biomedical applications.

  4. A proposed interplay between peroxidase, amine oxidase and lipoxygenase in the wounding-induced oxidative burst in Pisum sativum seedlings.

    Science.gov (United States)

    Roach, Thomas; Colville, Louise; Beckett, Richard P; Minibayeva, Farida V; Havaux, Michel; Kranner, Ilse

    2015-04-01

    Plant surfaces form the barrier between a plant and its environment. Upon damage, the wound healing process begins immediately and is accompanied by a rapid production of extracellular reactive oxygen species (ROS), essential in deterring pathogens, signalling responses and cell wall restructuring. Although many enzymes produce extracellular ROS, it is unclear if ROS-producing enzymes act synergistically. We characterised the oxidative burst of superoxide (O2(·-)) and hydrogen peroxide (H2O2) that follows wounding in pea (Pisum sativum L.) seedlings. Rates of ROS production were manipulated by exogenous application of enzyme substrates and inhibitors. The results indicate significant roles for di-amine oxidases (DAO) and peroxidases (Prx) rather than NADPH oxidase. The burst of O2(·-) was strongly dependent on the presence of H2O2 produced by DAO. Potential substrates released from wounded seedlings included linoleic acid that, upon exogenous application, strongly stimulated catalase-sensitive O2(·-) production. Moreover, a 65kD plasma membrane (PM) guaiacol Prx was found in the secretome of wounded seedlings and showed dependence on linoleic acid for O2(·-) production. Lipoxygenases are suggested to modulate O2(·-) production by consuming polyunsaturated fatty acids in the apoplast. Overall, a O2(·-)-producing mechanism involving H2O2-derived from DAO, linoleic acid and a PM-associated Prx is proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Copper-catalyzed direct amination of quinoline N-oxides via C-H bond activation under mild conditions.

    Science.gov (United States)

    Zhu, Chongwei; Yi, Meiling; Wei, Donghui; Chen, Xuan; Wu, Yangjie; Cui, Xiuling

    2014-04-04

    A highly efficient and concise one-pot strategy for the direct amination of quinoline N-oxides via copper-catalyzed dehydrogenative C-N coupling has been developed. The desired products were obtained in good to excellent yields for 22 examples starting from the parent aliphatic amines. This methodology provides a practical pathway to 2-aminoquinolines and features a simple system, high efficiency, environmental friendliness, low reaction temperature, and ligand, additives, base, and external oxidant free conditions.

  6. Spermidine but not spermine is essential for hypusine biosynthesis and growth in Saccharomyces cerevisiae: spermine is converted to spermidine in vivo by the FMS1-amine oxidase.

    Science.gov (United States)

    Chattopadhyay, Manas K; Tabor, Celia White; Tabor, Herbert

    2003-11-25

    In our earlier work we showed that either spermidine or spermine could support the growth of spe2Delta or spe3Delta polyamine-requiring mutants, but it was unclear whether the cells had a specific requirement for either of these amines. In the current work, we demonstrate that spermidine is specifically required for the growth of Saccharomyces cerevisiae. We were able to show this specificity by using a spe3Delta fms1Delta mutant that lacked both spermidine synthase and the FMS1-encoded amine oxidase that oxidizes spermine to spermidine. The polyamine requirement for the growth of this double mutant could only be satisfied by spermidine; i.e., spermine was not effective because it cannot be oxidized to spermidine in the absence of the FMS1 gene. We also showed that at least one of the reasons for the absolute requirement for spermidine for growth is the specificity of its function as a necessary substrate for the hypusine modification of eIF5A. Spermine itself cannot be used for the hypusine modification, unless it is oxidized to spermidine by the Fms1 amine oxidase. We have quantified the conversion of spermine in vivo and have shown that this conversion is markedly increased in a strain overexpressing the Fms1 protein. We have also shown this conversion in enzymatic studies by using the purified amine oxidase from yeast.

  7. Amine nitrosation via NO reduction of the polyamine copper(II) complex Cu(DAC)2+.

    Science.gov (United States)

    Khin, Chosu; Lim, Mark D; Tsuge, Kiyoshi; Iretskii, Alexei; Wu, Guang; Ford, Peter C

    2007-10-29

    The reaction of the fluorescent macrocyclic ligand 1,8-bis(anthracen-9-ylmethyl)-1,4,8,11-tetraazacyclotetradecane with copper(II) salts leads to formation of the Cu(DAC)2+ cation (I), which is not luminescent. However, when aqueous methanol solutions of I are allowed to react with NO, fluorescence again develops, owing to the formation of the strongly luminescent N-nitrosated ligand DAC-NO (II), which is released from the copper center. This reaction is relatively slow in neutral media, and kinetics studies show it to be first order in the concentrations of NO and base. In these contexts, it is proposed that the amine nitrosation occurs via NO attack at a coordinated amine that has been deprotonated and that this step occurs with concomitant reduction of the Cu(II) to Cu(I). DFT computations at the BP/LACVP* level support these mechanistic arguments. It is further proposed that such nitrosation of electron-rich ligands coordinated to redox-active metal centers is a mechanistic pathway that may find greater generality in the biochemical formation of nitrosothiols and nitrosoamines.

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

    Directory of Open Access Journals (Sweden)

    Renate Reiss

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

  9. Selective copper(II acetate and potassium iodide catalyzed oxidation of aminals to dihydroquinazoline and quinazolinone alkaloids

    Directory of Open Access Journals (Sweden)

    Matthew T. Richers

    2013-06-01

    Full Text Available Copper(II acetate/acetic acid/O2 and potassium iodide/tert-butylhydroperoxide systems are shown to affect the selective oxidation of ring-fused aminals to dihydroquinazolines and quinazolinones, respectively. These methods enable the facile preparation of a number of quinazoline alkaloid natural products and their analogues.

  10. Practical copper-catalyzed N-arylation of amines with 20% aqueous solution of n-Bu4NOH

    Institute of Scientific and Technical Information of China (English)

    Hamidreza Molaei; Mohammad Mehdi Ghanbari

    2012-01-01

    N-Arylation of a wide variety of amines with phenylboronic acid catalyzed by copper acetate under 20% aqueous solution of nBu4NOH was accomplished in good to excellent yields (up to 92%) and substrate conversions (up to 96%).

  11. Dietary Phenolic Compounds Interfere with the Fate of Hydrogen Peroxide in Human Adipose Tissue but Do Not Directly Inhibit Primary Amine Oxidase Activity

    Directory of Open Access Journals (Sweden)

    Christian Carpéné

    2016-01-01

    Full Text Available Resveratrol has been reported to inhibit monoamine oxidases (MAO. Many substrates or inhibitors of neuronal MAO interact also with other amine oxidases (AO in peripheral organs, such as semicarbazide-sensitive AO (SSAO, known as primary amine oxidase, absent in neurones, but abundant in adipocytes. We asked whether phenolic compounds (resveratrol, pterostilbene, quercetin, and caffeic acid behave as MAO and SSAO inhibitors. AO activity was determined in human adipose tissue. Computational docking and glucose uptake assays were performed in 3D models of human AO proteins and in adipocytes, respectively. Phenolic compounds fully inhibited the fluorescent detection of H2O2 generated during MAO and SSAO activation by tyramine and benzylamine. They also quenched H2O2-induced fluorescence in absence of biological material and were unable to abolish the oxidation of radiolabelled tyramine and benzylamine. Thus, phenolic compounds hampered H2O2 detection but did not block AO activity. Only resveratrol and quercetin partially impaired MAO-dependent [14C]-tyramine oxidation and behaved as MAO inhibitors. Phenolic compounds counteracted the H2O2-dependent benzylamine-stimulated glucose transport. This indicates that various phenolic compounds block downstream effects of H2O2 produced by biogenic or exogenous amine oxidation without directly inhibiting AO. Phenolic compounds remain of interest regarding their capacity to limit oxidative stress rather than inhibiting AO.

  12. Dietary Phenolic Compounds Interfere with the Fate of Hydrogen Peroxide in Human Adipose Tissue but Do Not Directly Inhibit Primary Amine Oxidase Activity.

    Science.gov (United States)

    Carpéné, Christian; Hasnaoui, Mounia; Balogh, Balázs; Matyus, Peter; Fernández-Quintela, Alfredo; Rodríguez, Víctor; Mercader, Josep; Portillo, Maria P

    2016-01-01

    Resveratrol has been reported to inhibit monoamine oxidases (MAO). Many substrates or inhibitors of neuronal MAO interact also with other amine oxidases (AO) in peripheral organs, such as semicarbazide-sensitive AO (SSAO), known as primary amine oxidase, absent in neurones, but abundant in adipocytes. We asked whether phenolic compounds (resveratrol, pterostilbene, quercetin, and caffeic acid) behave as MAO and SSAO inhibitors. AO activity was determined in human adipose tissue. Computational docking and glucose uptake assays were performed in 3D models of human AO proteins and in adipocytes, respectively. Phenolic compounds fully inhibited the fluorescent detection of H2O2 generated during MAO and SSAO activation by tyramine and benzylamine. They also quenched H2O2-induced fluorescence in absence of biological material and were unable to abolish the oxidation of radiolabelled tyramine and benzylamine. Thus, phenolic compounds hampered H2O2 detection but did not block AO activity. Only resveratrol and quercetin partially impaired MAO-dependent [(14)C]-tyramine oxidation and behaved as MAO inhibitors. Phenolic compounds counteracted the H2O2-dependent benzylamine-stimulated glucose transport. This indicates that various phenolic compounds block downstream effects of H2O2 produced by biogenic or exogenous amine oxidation without directly inhibiting AO. Phenolic compounds remain of interest regarding their capacity to limit oxidative stress rather than inhibiting AO.

  13. Synthesis of cytochrome c oxidase 1 (SCO1) inhibits insulin sensitivity by decreasing copper levels in adipocytes.

    Science.gov (United States)

    Wei, Xiang-Bo; Guo, Liang; Liu, Yang; Zhou, Shui-Rong; Liu, Yuan; Dou, Xin; Du, Shao-Yue; Ding, Meng; Peng, Wan-Qiu; Qian, Shu-Wen; Huang, Hai-Yan; Tang, Qi-Qun

    2017-09-23

    Dysregulation of insulin signaling leads to type 2 diabetes mellitus (T2DM) and other metabolic disorders. Obesity is an important contributor to insulin resistance, and although the understanding of this relationship has improved in recent years, the mechanism of obesity-induced insulin resistance is not completely understood. Disorders of copper metabolism tend to accompany the development of obesity, which increases the risk of insulin resistance. Synthesis of cytochrome c oxidase 1 (SCO1) functions in the assembly of cytochrome c oxidase (COX) and cellular copper homeostasis. However, the role of SCO1 in the regulation of metabolism remains unknown. Here, we found that obese mice had higher expression of SCO1 and lower levels of copper in white adipose tissue (WAT) than did the control mice. Overexpression of SCO1 in adipocytes was associated with copper deficiency. Copper increased insulin sensitivity by decreasing the level of phosphatase and tensin homolog (PTEN) protein. Ectopic expression of SCO1 led to insulin resistance and was accompanied by a decrease in intracellular copper level, and addition of copper abolished the inhibitory effect of SCO1 on insulin sensitivity. Our results demonstrated a novel role of SCO1 in modulating insulin sensitivity via the regulation of copper concentration in WAT and suggested a potential therapeutic target for T2DM. Copyright © 2017. Published by Elsevier Inc.

  14. Substrate specificity of the bovine serum amine oxidase and in situ characterisation of aminoaldehydes by NMR spectroscopy.

    Science.gov (United States)

    Houen, Gunnar; Struve, Casper; Søndergaard, Roar; Friis, Tina; Anthoni, Uffe; Nielsen, Per H; Christophersen, Carsten; Petersen, Bent O; Duus, Jens Ø

    2005-06-01

    The oxidation of spermidine or homospermidine with bovine serum amine oxidase (BSAO) was monitored in situ, using proton nuclear magnetic resonance spectroscopy in water with 10% D(2)O. NMR assignments were performed by spin decoupling and COSY spectra or by comparison with data from synthetic aminoaldehydes. The results represent the first in situ characterisation of the highly reactive aminoaldehydes and showed oxidation at the N(1) amino group of spermidine and homospermidine. Comparison of homospermidine with a variety of substrates revealed that among straight chain di- and polyamines both an aminopropyl group and two primary amino groups separated by seven (norspermidine) or eight (spermidine) carbon atoms were required for optimal substrate ability. However, highest activity was seen with the substrate N-(4-aminobutyl)hexahydropyrimidine, showing that the substrate channel of BSAO has a dual substrate preference, with moderately bulky substituents at the distal end of a diamine contributing equally well as an alkyl amino group. Cytotoxic investigations of a variety of substrates for BSAO, confirmed previous results, that cytotoxicity is primarily linked to polyamines encompassing the aminopropyl moiety. No acrolein was observed at any time during the oxidation showing that it reacts very fast with available amino groups forming a variety of derivatives.

  15. Cultured rat vascular smooth muscle cells are resistant to methylamine toxicity: no correlation to semicarbazide-sensitive amine oxidase

    Science.gov (United States)

    Langford, S. D.; Trent, M. B.; Boor, P. J.

    2001-01-01

    Methylamine (MA), a component of serum and a metabolite of nicotine and certain insecticides and herbicides, is metabolized by semicarbazide-sensitive amine oxidase (SSAO). MA is toxic to cultured human umbilical vein and calf pulmonary artery endothelial cells. Endothelial cells, which do not exhibit endogenous SSAO activity, are exposed to SSAO circulating in serum. In contrast, vascular smooth muscle cells (VSMC) do exhibit innate SSAO activity both in vivo and in vitro. This property, together with the critical localization of VSMC within the arterial wall, led us to investigate the potential toxicity of MA to VSMC. Cultured rat VSMC were treated with MA (10-5 to 1 M). In some cultures, SSAO was selectively inhibited with semicarbazide or MDL-72145 [(E)-2-(3,4-dimethoxyphenyl)-3-fluoroallylamine]. Cytotoxicity was measured via MTT, vital dye exclusion, and clonogenic assays. MA proved to be toxic to VSMC only at relatively high concentrations (LC(50) of 0.1 M). The inhibition of SSAO with semicarbazide or MDL-72145 did not increase MA toxicity, suggesting that the production of formaldehyde via tissue-bound, SSAO-mediated MA metabolism does not play a role in the minimal toxicity observed in isolated rat VSMC. The omission of fetal calf serum (FCS), which contains high SSAO activity, from media similarly showed little effect on cytotoxicity. We conclude that VSMC--in contrast to previous results in endothelial cells--are relatively resistant to MA toxicity, and SSAO does not play a role in VSMC injury by MA.

  16. Enhancement of hydralazine hypotension by low doses of isoniazid. Possible role of semicarbazide-sensitive amine oxidase inhibition.

    Science.gov (United States)

    Vidrio, H; Medina, M; Fernandez, G; Lorenzana-Jimenez, M; Campos, A E

    2000-10-01

    The influence of pretreatment with 1 through 300 mg/kg ip of isoniazid (ISO) on blood pressure and heart rate responses to 0.1 mg/kg iv of hydralazine (HYD) was assessed in rats anesthetized with chloralose--urethane. HYD hypotension was significantly enhanced by ISO at doses between 3 and 300 mg/kg ip. Heart rate was not influenced by HYD in control or pretreated animals. Depressor responses to 0.2 mg/kg iv of pinacidil (PIN) were also potentiated by ISO at 100 and 300, but not at 30 mg/kg. Similarly, ISO decreased cerebral gamma-aminobutyric acid (GABA) at the two highest doses; 30 mg/kg was without effect. Pretreatment of rats with ISO at 1 through 300 mg/kg failed to influence HYD-induced relaxation of aortic rings. These results were interpreted as indicating that potentiation of HYD hypotension by high doses of ISO is not specific for that vasodilator and is related to decreased cerebral GABA, as postulated previously. Lower doses could specifically potentiate the HYD-induced hypotensive effect by inhibition of semicarbazide-sensitive amine oxidase (SSAO), since both ISO and HYD are potent inhibitors of this enzyme. In support of this hypothesis, the SSAO inhibitors, benserazide (100 mg/kg ip) and mexiletine (50 mg/kg ip), were also found to enhance HYD hypotension.

  17. Crystal structures of two mixed-valence copper cyanide complexes with N-methyl-ethylenedi-amine.

    Science.gov (United States)

    Corfield, Peter W R; Sabatino, Alexander

    2017-02-01

    The crystal structures of two mixed-valence copper cyanide compounds involving N-methyl-ethylenedi-amine (meen), are described. In compound (I), poly[bis(μ3-cyanido-κ3C:C:N)tris(μ2-cyanido-κ2C:N)bis(N-methylethane-1,2-di-amine-κ2N,N')tricopper(I)copper(II)], [Cu4(CN)5(C3H10N2)2] or Cu4(CN)5meen2, cyanide groups link Cu(I) atoms into a three-dimensional network containing open channels parallel to the b axis. In the network, two tetra-hedrally bound Cu(I) atoms are bonded by the C atoms of two end-on bridging CN groups to form Cu2(CN)6 moieties with the Cu atoms in close contact at 2.560 (1) Å. Other trigonally bound Cu(I) atoms link these units together to form the network. The Cu(II) atoms, coordinated by two meen units, are covalently linked to the network via a cyanide bridge, and project into the open network channels. In the mol-ecular compound (II), [(N-methylethylenediamine-κ(2)N,N')copper(II)]-μ(2)-cyanido-κ(2)C:N-[bis(cyanido-κC)copper(I)] monohydrate, [Cu2(CN)3(C3H10N2)2]·H2O or Cu2(CN)3meen2·H2O, a CN group connects a Cu(II) atom coordinated by two meen groups with a trigonal-planar Cu(I) atom coordinated by CN groups. The mol-ecules are linked into centrosymmetric dimers via hydrogen bonds to two water mol-ecules. In both compounds, the bridging cyanide between the Cu(II) and Cu(I) atoms has the N atom bonded to Cu(II) and the C atom bonded to Cu(I), and the Cu(II) atoms are in a square-pyramidal coordination.

  18. Cooperative coupling and role of heme a in the proton pump of heme-copper oxidases.

    Science.gov (United States)

    Papa, S; Capitanio, N; Villani, G; Capitanio, G; Bizzoca, A; Palese, L L; Carlino, V; De Nitto, E

    1998-10-01

    In the last few years, evidence has accumulated supporting the applicability of the cooperative model of proton pumps in cytochrome systems, vectorial Bohr mechanisms, to heme-copper oxidases. The vectorial Bohr mechanism is based on short- and long-range protonmotive cooperative effects linked to redox transitions of the metal centers. The crystal structure of oxidized and reduced bovine-heart cytochrome c oxidase reveals, upon reduction, the occurrence of long-range conformational changes in subunit I of the oxidase. Analysis of the crystal structure of cytochrome c oxidase shows the existence of hydrogen-bonded networks of amino acid residues which could undergo redox-linked pK shifts resulting in transmembrane proton translocation. Our group has identified four proteolytic groups undergoing reversible redox-linked pK shifts. Two groups result in being linked to redox transitions of heme a3. One group is apparently linked to CuB. The fourth group is linked to oxido-reduction of heme a. We have shown that the proton transfer resulting from the redox Bohr effects linked to heme a and CuB in the bovine oxidase displays membrane vectorial asymmetry, i.e., protons are taken up from the inner aqueous space (N), upon reduction, and released in the external space (P), upon oxidation of the metals. This direction of proton uptake and release is just what is expected from the vectorial Bohr mechanism. The group linked to heme a, which can transfer up to 0.9 H+/e- at pHs around neutrality, can provide the major contribution to the proton pump. It is proposed that translocation of pumped protons, linked to electron flow through heme a, utilizes a channel (channel D) which extends from a conserved aspartate at the N entrance to a conserved glutamate located between heme a and the binuclear center. The carboxylic group of this glutamic acid, after having delivered, upon electron flow through heme a, pumped protons towards the P phase, once reprotonated from the N phase, moves

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Copper-catalyzed aerobic oxidative C-C bond cleavage of unstrained ketones with air and amines.

    Science.gov (United States)

    Zhou, Wang; Fan, Wenyou; Jiang, Qijian; Liang, Yu-Feng; Jiao, Ning

    2015-05-15

    A unique copper-catalyzed aerobic oxidative C-C bond cleavage of simple unstrained ketones with air and amines has been developed. In this chemistry, amides and oxo amides are easily synthesized through the selective C-C bond cleavage of simple ketones or unstrained cycloketones. The broad substrate scopes and use of an inexpensive copper catalyst and green molecular oxygen as an oxidant as well as an O-source make this protocol very attractive for potential synthetic applications. The control experiments reveal that the present copper-catalyzed oxidative C-C bond cleavage of simple ketones proceeds in a novel catalytic pathway rather than through the cleavage of a dioxetane intermediate.

  1. Reassessment of the active site quino-cofactor proposed to occur in the Aspergillus niger amine oxidase AO-I from the properties of model compounds.

    Science.gov (United States)

    Melville, C R; Green, E L; Sanders-Loehr, J; Klinman, J P

    2000-06-27

    Quino-cofactors have been found in a wide variety of prokaryotic and eukaryotic organisms. Two variants have, thus far, been demonstrated to derive from tyrosine precursors: these are the 2,4, 5-trihydroxyphenylalanine quinone (topa quinone or TPQ) [Janes, S. M. , et al. (1990) Science 248, 98] and an o-quinone analogue containing the side chain of a lysine residue (lysyltyrosine quinone or LTQ) [Wang, S. Z., et al. (1996) Science 273, 1078]. Additionally, a third variant of the family of tyrosine-derived cofactors has been reported to exist in an Aspergillus niger amine oxidase AO-I. This was described as an o-quinone cross-linked to the side chain of a glutamate residue [Frebort, I. (1996) Biochim. Biophys. Acta 1295, 59]. We have synthesized model compounds related to the proposed structure. Characterization of the redox properties for the model compound and spectral properties of its 4-nitrophenylhydrazine derivative lead us to conclude that the cofactor in A. niger amine oxidase AO-I has been misidentified. A TPQ carboxylate ester is considered an unlikely candidate for a biologically functional quino-cofactor.

  2. Single step synthesis of amine-functionalized mesoporous magnetite nanoparticles and their application for copper ions removal from aqueous solution.

    Science.gov (United States)

    Gao, Jining; He, Yingjuan; Zhao, Xianying; Ran, Xinze; Wu, Yonghui; Su, Yongping; Dai, Jianwu

    2016-11-01

    Amine-functionalized mesoporous superparamagnetic Fe3O4 nanoparticles with an average size of 70nm have been synthesized using a single step solvothermal method by the introduction of triethylenetetramine (TETA), a chelating agent recommended for the removal of excess copper in patients with Wilson's disease. The synthesized nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption/desorption isotherm, vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR). It is confirmed that the magnetic nanoparticles have been functionalized with TETA during the synthetic process, and the concentration of TETA is crucial for the formation of monodisperse mesoporous nanoparticles. The obtained single-crystal magnetic nanoparticles have a high magnetization, which enhances their response to external magnetic field and therefore should greatly facilitate the manipulation of the particles in practical uses. Reaction parameters affecting the formation of mesoporous structure were explored, and a possible formation mechanism involving templated aggregation and recrystallization processes was proposed. The capacity of the synthesized amine-functionalized Fe3O4 nanoparticles toward Cu(II) removal from aqueous solution was investigated. The adsorption rate of Cu(II) on amine-functionalized Fe3O4 nanoparticles followed a pseudo-second order kinetic model. The results of this study demonstrated that the amine-functionalized mesoporous superparamagnetic Fe3O4 nanoparticles could be used as an efficient adsorbent in water treatment and would also find potential application for Cu(II) removal in vivo.

  3. Purification and characterization of methylamine oxidase induced in Aspergillus niger AKU 3302.

    Science.gov (United States)

    Frébort, I; Matsushita, K; Toyama, H; Lemr, K; Yamada, M; Adachi, O

    1999-01-01

    Crude extract of Aspergillus niger AKU 3302 mycelia incubated with methylamine showed a single amine oxidase activity band in a developed polyacrylamide gel that weakly cross-reacted with the antibody against a copper/topa quinone-containing amine oxidase (AO-II) from the same strain induced by n-butylamine. Since the organism cannot grow on methylamine and the already known quinoprotein amine oxidases of the organism cannot catalyze oxidation of methylamine, the organism was forced to produce another enzyme that could oxidize methylamine when the mycelia were incubated with methylamine. The enzyme was separated and purified from the already known two quinoprotein amine oxidases formed in the same mycelia. The purified enzyme showed a sharp symmetric sedimentation peak in analytical ultracentrifugation showing S20,w0 of 6.5s. The molecular mass of 133 kDa estimated by gel chromatography and 66.6 kDa found by SDS-PAGE confirmed the dimeric structure of the enzyme. The purified enzyme was pink in color with an absorption maximum at 494 nm. The enzyme readily oxidized methylamine, n-hexylamine, and n-butylamine, but not benzylamine, histamine, or tyramine, favorite substrates for the already known two quinoprotein amine oxidases. Inactivation by carbonyl reagents and copper chelators suggested the presence of a copper/topa quinone cofactor. Spectrophotometric titration by p-nitrophenylhydrazine showed one reactive carbonyl group per subunit and redox-cyclic quinone staining confirmed the presence of a quinone cofactor. pH-dependent shift of the absorption spectrum of the enzyme-p-nitrophenylhydrazone (469 nm at neutral to 577 nm at alkaline pH) supported the identity of the cofactor with topaquinone. Nothern blot analysis indicated that the methylamine oxidase encoding gene is largely different from the already known amine oxidase in the organism.

  4. Synthesis of quinazolines and tetrahydroquinazolines: copper-catalyzed tandem reactions of 2-bromobenzyl bromides with aldehydes and aqueous ammonia or amines.

    Science.gov (United States)

    Fan, Xuesen; Li, Bin; Guo, Shenghai; Wang, Yuanyuan; Zhang, Xinying

    2014-03-01

    An efficient synthesis of diversely substituted quinazolines and 1,2,3,4-tetrahydroquinazolines through copper-catalyzed tandem reactions of the readily available 2-bromobenzyl bromides, aldehydes, and aqueous ammonia or amines has been developed. By using ammonia and simple aliphatic amines as the nitrogen source, the present method provides a versatile and practical protocol for the synthesis of quinazolines and 1,2,3,4-tetrahydroquinazolines.

  5. Site-specific indolation of proline-based peptides via copper(II)-catalyzed oxidative coupling of tertiary amine N-oxides.

    Science.gov (United States)

    Wu, Xiaowei; Zhang, Dengyou; Zhou, Shengbin; Gao, Feng; Liu, Hong

    2015-08-14

    The first site-specific and purely chemical method for modifying proline-based peptides was developed via a convenient, copper-catalyzed oxidative coupling of tertiary amine N-oxides with indoles. This novel approach features high regioselectivity and diastereoselectivity, mild conditions, and compatibility with various functional groups. In addition, a simplified process was realized in one pot and two steps via in situ oxidative coupling of tertiary amine and indoles.

  6. Modifications of laccase activities of copper efflux oxidase, CueO by synergistic mutations in the first and second coordination spheres of the type I copper center.

    Science.gov (United States)

    Kataoka, Kunishige; Kogi, Hiroki; Tsujimura, Seiya; Sakurai, Takeshi

    2013-02-15

    The redox potential of type I copper in the Escherichia coli multicopper oxidase CueO was shifted in the positive or negative direction as a result of the single, double, and triple mutations in the first and second coordination spheres: the formation of the NH···S(-)(Cys500 ligand) hydrogen bond, the breakdown of the NH(His443 ligand)···O(-)(Asp439) hydrogen bond, and the substitution of the Met510 ligand for the non-coordinating Leu or coordinating Gln. Laccase activities of CueO were maximally enhanced 140-fold by virtue of the synergistic effect of mild mutations at and at around the ligand groups to type I copper.

  7. Copper-catalyzed α-amination of phosphonates and phosphine oxides: a direct approach to α-amino phosphonic acids and derivatives.

    Science.gov (United States)

    McDonald, Stacey L; Wang, Qiu

    2014-02-10

    A direct approach to important α-amino phosphonic acids and its derivatives has been developed by using copper-catalyzed electrophilic amination of α-phosphonate zincates with O-acyl hydroxylamines. This amination provides the first example of CN bond formation which directly introduces acyclic and cyclic amines to the α-position of phosphonates in one step. The reaction is readily promoted at room temperature with as little as 0.5 mol % of catalyst, and demonstrates high efficiency on a broad substrate scope.

  8. Assignment of Soret MLCT band of reduced form of copper binuclear cluster in cytochrome c oxidase film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Low concentration of dithionite results in the reduction of Cu-Cu binuclear and heme a active sites of the cytochrome c oxidase thin solid film immersed in the acidic phosphate buffer, but Fe-Cu binuclear center keeps in the oxidation state. It manifests as a negative peak at 426 nm and a positive one at ~408 nm in the difference spectra induced by dithionite. The former implies decrease of the oxidized form of heme a center, that is, Fea3+→Fea2+. And the latter results from the contribution of metal-ligand charge transfer (MLCT) transition in the reduced binuclear Cu-Cu cluster, rather than from that of heme a center. This stronger Soret MLCT band must be helpful to overcoming the difficulty in distinguishing the weaker copper sign from the stronger one of iron when studying copper-iron protein.

  9. The activity of ascorbic acid and catechol oxidase, the rate of photosynthesis and respiration as related to plant organs, stage of development and copper supply

    Directory of Open Access Journals (Sweden)

    St. Łyszcz

    2015-06-01

    Full Text Available Some experiments were performed to investigate the physiological role of copper in oat and sunflower and to recognize some effects of copper deficiency. Oat and sunflower plants were grown in pots on a peat soil under copper deficiency conditions (–Cu or with the optimal copper supply (+Cu. In plants the following measurements were carried out: 1 the activity of ascorbic acid oxidase (AAO and of catechol oxidase (PPO in different plant organs and at different stages of plant development, 2 the activity and the rate of photosynthesis, 3 the activity of RuDP-carboxylase, 4 the intensity of plant respiration. The activity of AAO and of PPO, and also the rate and the activity of photosynthesis were significantly lower under conditions of copper deficiency. The activity of both discussed oxidases depended on: 1 the plant species, 2 plant organs, 3 stage of plant development. Copper deficiency caused decrease of the respiration intensity of sunflower leaves but it increased to some extent the respiration of oat tops. Obtained results are consistent with the earlier suggestion of the authors that the PPO activity in sunflower leaves could be a sensitive indicator of copper supply of the plants, farther experiments are in progress.

  10. Human retina-specific amine oxidase: genomic structure of the gene (AOC2), alternatively spliced variant, and mRNA expression in retina.

    Science.gov (United States)

    Imamura, Y; Noda, S; Mashima, Y; Kudoh, J; Oguchi, Y; Shimizu, N

    1998-07-15

    Previously, we reported the isolation of cDNA for human retina-specific amine oxidase (RAO) and the expression of RAO exclusively in retina. Bacterial artificial chromosome clones containing the human RAO gene (AOC2) were mapped to human chromosome 17q21 (Imamura et al., 1997, Genomics 40: 277-283). Here, we report the complete genomic structure of the RAO gene, including 5' flanking sequence, and mRNA expression in retina. The human RAO gene spans 6 kb and is composed of four exons corresponding to the amino acid sequence 1-530, 530-598, 598-641, and 642-729 separated by three introns of 3000, 310, and 351 bp. Screening of a human retina cDNA library revealed the existence of an alternatively spliced cDNA variant with an additional 81 bp at the end of exon 2. The sizes of exons and the locations of exon/intron boundaries in the human RAO gene showed remarkable similarity to those of the human kidney diamine oxidase gene (AOC1). In situ hybridization revealed that mRNA coding for RAO is expressed preferentially in the ganglion cell layer of the mouse retina. We designed four sets of PCR primers to amplify four exons, which will be valuable for analyzing mutations in patients with ocular diseases affecting the retinal ganglion cell layer.

  11. Effects of copper amine treatments on mechanical, biological and surface/interphase properties of poly (vinyl chloride)/wood composites

    Science.gov (United States)

    Jiang, Haihong

    2005-11-01

    The copper ethanolamine (CuEA) complex was used as a wood surface modifier and a coupling agent for wood-PVC composites. Mechanical properties of composites, such as unnotched impact strength, flexural strength and flexural toughness, were significantly increased, and fungal decay weight loss was dramatically decreased by wood surface copper amine treatments. It is evident that copper amine was a very effective coupling agent and decay inhibitor for PVC/wood flour composites, especially in high wood flour loading level. A DSC study showed that the heat capacity differences (DeltaCp) of composites before and after PVC glass transition were reduced by adding wood particles. A DMA study revealed that the movements of PVC chain segments during glass transition were limited and obstructed by the presence of wood molecule chains. This restriction effect became stronger by increasing wood flour content and by using Cu-treated wood flour. Wood flour particles acted as "physical cross-linking points" inside the PVC matrix, resulting in the absence of the rubbery plateau of PVC and higher E', E'' above Tg, and smaller tan delta peaks. Enhanced mechanical performances were attributed to the improved wetting condition between PVC melts and wood surfaces, and the formation of a stronger interphase strengthened by chemical interactions between Cu-treated wood flour and the PVC matrix. Contact angles of PVC solution drops on Cu-treated wood surfaces were decreased dramatically compared to those on the untreated surfaces. Acid-base (polar), gammaAB, electron-acceptor (acid) (gamma +), electron-donor (base) (gamma-) surface energy components and the total surface energies increased after wood surface Cu-treatments, indicating a strong tendency toward acid-base or polar interactions. Improved interphase and interfacial adhesion were further confirmed by measuring interfacial shear strength between wood and the PVC matrix.

  12. Study on dioxygen reduction by mutational modifications of the hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Hirotoshi; Kurita, Daisuke; Kataoka, Kunishige; Sakurai, Takeshi, E-mail: tsakurai@se.kanazawa-u.ac.jp

    2014-07-18

    Highlights: • Proton transport pathway in bilirubin oxidase was mutated. • Two intermediates in the dioxygen reduction steps were trapped and characterized. • A specific glutamate for dioxygen reduction by multicopper oxidases was identified. - Abstract: The hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase is constructed with Glu463 and water molecules to transport protons for the four-electron reduction of dioxygen. Substitutions of Glu463 with Gln or Ala were attributed to virtually complete loss or significant reduction in enzymatic activities due to an inhibition of the proton transfer steps to dioxygen. The single turnover reaction of the Glu463Gln mutant afforded the highly magnetically interacted intermediate II (native intermediate) with a broad g = 1.96 electron paramagnetic resonance signal detectable at cryogenic temperatures. Reactions of the double mutants, Cys457Ser/Glu463Gln and Cys457Ser/Glu463Ala afforded the intermediate I (peroxide intermediate) because the type I copper center to donate the fourth electron to dioxygen was vacant in addition to the interference of proton transport due to the mutation at Glu463. The intermediate I gave no electron paramagnetic resonance signal, but the type II copper signal became detectable with the decay of the intermediate I. Structural and functional similarities between multicopper oxidases are discussed based on the present mutation at Glu463 in bilirubin oxidase.

  13. Prenatal copper deficiency in rat dams causes persistent reduction in nuclear-encoded cytochrome c oxidase subunits in cardiac mitochrondria of the first generation

    Science.gov (United States)

    Previous studies have shown that the offspring of rat dams having low copper (Cu) intake during pregnancy and lactation experience a deficiency in cardiac cytochrome c oxidase (CCO) after postnatal day 10. The present study was undertaken to determine the relative influences of pre-and postnatal Cu ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-25

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

  15. Models for the active site in galactose oxidase: Structure, spectra and redox of copper(II) complexes of certain phenolate ligands

    Indian Academy of Sciences (India)

    Mathrubootham Vaidyanathan; Mallayan Palaniandavar

    2000-06-01

    Galactose oxidase (GOase) is a fungal enzyme which is unusual among metalloenzymes in appearing to catalyse the two electron oxidation of primary alcohols to aldehydes and H2O2. The crystal structure of the enzyme reveals that the coordination geometry of mononuclear copper(II) ion is square pyramidal, with two histidine imidazoles, a tyrosinate, and either H2O (H 7.0) or acetate (from buffer, H 4.5) in the equatorial sites and a tyrosinate ligand weakly bound in the axial position. This paper summarizes the results of our studies on the structure, spectral and redox properties of certain novel models for the active site of the inactive form of GOase. The monophenolato Cu(II) complexes of the type [Cu(L1)X][H(L1) = 2-(bis(pyrid-2-ylmethyl)aminomethyl)-4-nitrophenol and X-= Cl-1, NCS-2, CH3COO-3, ClO$_{4}^{-}$ 4] reveal a distorted square pyramidal geometry around Cu(II) with an unusual axial coordination of phenolate moiety. The coordination geometry of 3 is reminiscent of the active site of GOase with an axial phenolate and equatorial CH3COO- ligands. All the present complexes exhibit several electronic and EPR spectral features which are also similar to the enzyme. Further, to establish the structural and spectroscopic consequences of the coordination of two tyrosinates in GOase enzyme, we studied the monomeric copper(II) complexes containing two phenolates and imidazole/pyridine donors as closer structural models for GOase. N,Ndimethylethylenediamine and N,N -dimethylethylenediamine have been used as starting materials to obtain a variety of 2,4-disubstituted phenolate ligands. The X-ray crystal structures of the complexes [Cu(L5)(py)], (8) [H2 (L5) = N,N-dimethyl-N ,N -bis(2-hydroxy-4-nitrobenzyl) ethylenediamine, py = pyridine] and [Cu(L8)(H2O)] (11), [H2(L8) = N,N -dimethyl-N,N -bis(2-hydroxy-4-nitrobenzyl)ethylenediamine] reveal distorted square pyramidal geometries around Cu(II) with the axial tertiary amine nitrogen and water coordination respectively

  16. Synthetic liver X receptor agonist T0901317 inhibits semicarbazide-sensitive amine oxidase gene expression and activity in apolipoprotein E knockout mice

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan Dai; Xiang Ou; Xinrui Hao; Dongli Cao; Yaling Tang; Yanwei Hu; Xiaoxu Li; Chaoke Tang

    2008-01-01

    Semicarbazide-sensitive amine oxidase(SSAO)catalyzes oxidative deamination of primary aromatic and aliphatic amines.Increased SSAO activity has been found in atherosclerosis and diabetes mellitus.We hypothesize that the anti-atherogenic effect of liver X receptors(LXRs)might be related to the inhibition of SSAD gene expression and its activity.In this study,we investigated the effect of LXR agonist T0901317 on SSAO gene expression and its activity in apolipoprotein E knockout(apoE-/-)mice.Male apoE-/-mice(8 weeks old) were randomly divided into four groups:basal control group;vehicle group;prevention group;and treatment group.SSAO gene expression was analyzed by real-time quantitative polymerase chain reaction and its activity was determined.The activity of superoxide dismutase and content of malondialdehy de in the aorta and liver were also determined.In T0901317-treated mice,SSAO gene expression was significantly decreased in the aorta,liver,small intestine,and brain.SSAO activities in serum and in these tissues were also inhibited.The amount of superoxide dismutase in the aorta and liver of the prevention group and treatment group was significantly higher compared with the vehicle group(P<0.05).Malondialdehyde in the tissues of these two groups was significantly lower compared with the vehicle group(P<0.05).Our results showed that T0901317 inhibits SSAO gene expression and its activity in atherogenic apoE-/-mice.The atheroprotective effect of LXR agonist T0901317 is related to the inhibition of SSAO gene expression and its activity.

  17. Copper and bezafibrate cooperate to rescue cytochrome c oxidase deficiency in cells of patients with sco2 mutations

    Directory of Open Access Journals (Sweden)

    Casarin Alberto

    2012-04-01

    Full Text Available Abstract Background Mutations in SCO2 cause cytochrome c oxidase deficiency (COX and a fatal infantile cardioencephalomyopathy. SCO2 encodes a protein involved in COX copper metabolism; supplementation with copper salts rescues the defect in patients’ cells. Bezafibrate (BZF, an approved hypolipidemic agent, ameliorates the COX deficiency in mice with mutations in COX10, another COX-assembly gene. Methods We have investigated the effect of BZF and copper in cells with SCO2 mutations using spectrophotometric methods to analyse respiratory chain activities and a luciferase assay to measure ATP production.. Results Individual mitochondrial enzymes displayed different responses to BZF. COX activity increased by about 40% above basal levels (both in controls and patients, with SCO2 cells reaching 75-80% COX activity compared to untreated controls. The increase in COX was paralleled by an increase in ATP production. The effect was dose-dependent: it was negligible with 100 μM BZF, and peaked at 400 μM BZF. Higher BZF concentrations were associated with a relative decline of COX activity, indicating that the therapeutic range of this drug is very narrow. Combined treatment with 100 μM CuCl2 and 200 μM BZF (which are only marginally effective when administered individually achieved complete rescue of COX activity in SCO2 cells. Conclusions These data are crucial to design therapeutic trials for this otherwise fatal disorder. The additive effect of copper and BZF will allow to employ lower doses of each drug and to reduce their potential toxic effects. The exact mechanism of action of BZF remains to be determined.

  18. Citric Acid Enhanced Copper Removal by a Novel Multi-amines Decorated Resin

    Science.gov (United States)

    Ling, Chen; Liu, Fuqiang; Pei, Zhiguo; Zhang, Xiaopeng; Wei, Mengmeng; Zhang, Yanhong; Zheng, Lirong; Zhang, Jing; Li, Aimin; Xing, Baoshan

    2015-05-01

    Cu removal by a novel multi-amines decorated resin (PAMD) from wastewater in the absence or presence of citric acid (CA) was examined. Adsorption capacity of Cu onto PAMD markedly increased by 186% to 5.07 mmol/g in the presence of CA, up to 7 times of that onto four commercial resins under the same conditions. Preloaded and kinetic studies demonstrated adsorption of [Cu-CA] complex instead of CA site-bridging and variations of adsorbate species were qualitatively illustrated. The interaction configuration was further studied with ESI-MS, FTIR, XPS and XANES characterizations. The large enhancement of Cu adsorption in Cu-CA bi-solutes systems was attributed to mechanism change from single-site to dual-sites interaction in which cationic or neutral Cu species (Cu2+ and CuHL0) coordinated with neutral amine sites and anionic complex species (CuL- and Cu2L22-) directly interacted with protonated amine sites via electrostatic attraction, and the ratio of the two interactions was approximately 0.5 for the equimolar bi-solutes system. Moreover, commonly coexisting ions in wastewaters had no obvious effect on the superior performance of PAMD. Also, Cu and CA could be recovered completely with HCl. Therefore, PAMD has a great potential to efficiently remove heavy metal ions from wastewaters in the presence of organic acids.

  19. IN ABSENCE OF THE CELLULAR PRION PROTEIN, ALTERATIONS IN COPPER METABOLISM AND COPPER-DEPENDENT OXIDASE ACTIVITY AFFECT IRON DISTRIBUTION

    OpenAIRE

    Lisa Gasperini; Elisa Meneghetti; Giuseppe Legname; Federico Benetti

    2016-01-01

    Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defin...

  20. In Absence of the Cellular Prion Protein, Alterations in Copper Metabolism and Copper-Dependent Oxidase Activity Affect Iron Distribution

    OpenAIRE

    Gasperini, Lisa; Meneghetti, Elisa; Legname, Giuseppe; Benetti, Federico

    2016-01-01

    Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defin...

  1. Citric Acid Enhanced Copper Removal by a Novel Multi-amines Decorated Resin

    OpenAIRE

    Chen Ling; Fuqiang Liu; Zhiguo Pei; Xiaopeng Zhang; Mengmeng Wei; Yanhong Zhang; Lirong Zheng; Jing Zhang; Aimin Li; Baoshan Xing

    2015-01-01

    Cu removal by a novel multi-amines decorated resin (PAMD) from wastewater in the absence or presence of citric acid (CA) was examined. Adsorption capacity of Cu onto PAMD markedly increased by 186% to 5.07 mmol/g in the presence of CA, up to 7 times of that onto four commercial resins under the same conditions. Preloaded and kinetic studies demonstrated adsorption of [Cu-CA] complex instead of CA site-bridging and variations of adsorbate species were qualitatively illustrated. The interaction...

  2. Copper(I) thiocyanate-amine networks: synthesis, structure, and luminescence behavior.

    Science.gov (United States)

    Miller, Kayla M; McCullough, Shannon M; Lepekhina, Elena A; Thibau, Isabelle J; Pike, Robert D; Li, Xiaobo; Killarney, James P; Patterson, Howard H

    2011-08-01

    A series of metal-organic networks of CuSCN were prepared by direct reactions with substituted pyridine and aliphatic amine ligands, L. Thiocyanate bridging is seen in all but 1 of 11 new X-ray structures. Structures are reported for (CuSCN)L sheets (L = 3-chloro- and 3-bromopyridine, N-methylmorpholine), ladders (L = 2-ethylpyridine, N-methylpiperidine), and chains (L = 2,4,6-collidine). X-ray structures of (CuSCN)L(2) are chains (L = 4-ethyl- and 4-t-butylpyridine, piperidine, and morpholine). A unique N-thiocyanato monomer structure, (CuSCN)(3-ethylpyridine)(3), is also reported. In most cases, amine ligands are thermally released at temperatures temperature is observed for the substituted pyridine complexes. High solid state quantum efficiencies are seen for many of the CuSCN-L complexes. Microsecond phosphorescence lifetimes seen for CuSCN-L are in direct contrast to the nanosecond-lifetime emission of CuSCN. MLCT associated with pyridine π* orbitals is proposed as the excitation mechanism. © 2011 American Chemical Society

  3. Properties and ATRP activity of copper complexes with substituted tris(2-pyridylmethyl)amine-based ligands.

    Science.gov (United States)

    Kaur, Aman; Ribelli, Thomas G; Schröder, Kristin; Matyjaszewski, Krzysztof; Pintauer, Tomislav

    2015-02-16

    Synthesis, characterization, electrochemical studies, and ATRP activity of a series of novel copper(I and II) complexes with TPMA-based ligands containing 4-methoxy-3,5-dimethyl-substituted pyridine arms were reported. In the solid state, Cu(I)(TPMA*(1))Br, Cu(I)(TPMA*(2))Br, and Cu(I)(TPMA*(3))Br complexes were found to be distorted tetrahedral in geometry and contained coordinated bromide anions. Pseudo-coordination of the aliphatic nitrogen atom to the copper(I) center was observed in Cu(I)(TPMA*(2))Br and Cu(I)(TPMA*(3))Br complexes, whereas pyridine arm dissociation occurred in Cu(I)(TPMA*(1))Br. All copper(I) complexes with substituted TPMA ligands exhibited a high degree of fluxionality in solution. At low temperature, Cu(I)(TPMA*(1))Br was found to be symmetrical and monomeric, while dissociation of either unsubstituted pyridine and/or 4-methoxy-3,5-dimethyl-substituted pyridine arms was observed in Cu(I)(TPMA*(2))Br and Cu(I)(TPMA*(3))Br. On the other hand, the geometry of the copper(II) complexes in the solid state deviated from ideal trigonal bipyramidal, as confirmed by a decrease in τ values ([Cu(II)(TPMA*(1))Br][Br] (τ = 0.92) > [Cu(II)(TPMA*(3))Br][Br] (τ = 0.77) > [Cu(II)(TPMA*(2))Br][Br] (τ = 0.72)). Furthermore, cyclic voltammetry studies indicated a nearly stepwise decrease (ΔE ≈ 60 mV) of E1/2 values relative to SCE (TPMA (-240 mV) > TPMA*(1) (-310 mV) > TPMA*(2) (-360 mV) > TPMA*(3) (-420 mV)) on going from [Cu(II)(TPMA)Br][Br] to [Cu(II)(TPMA*(3))Br][Br], confirming that the presence of electron-donating groups in the 4 (-OMe) and 3,5 (-Me) positions of the pyridine rings in TPMA increases the reducing ability of the corresponding copper(I) complexes. This increase was mostly the result of a stronger influence of substituted TPMA ligands toward stabilization of the copper(II) oxidation state (log β(I) = 13.4 ± 0.2, log β(II) = 19.3 (TPMA*(1)), 20.5 (TPMA*(2)), and 21.5 (TPMA*(3))). Lastly, ARGET ATRP kinetic studies show that with

  4. Practical aerobic oxidations of alcohols and amines with homogeneous copper/TEMPO and related catalyst systems.

    Science.gov (United States)

    Ryland, Bradford L; Stahl, Shannon S

    2014-08-18

    Oxidations of alcohols and amines are common reactions in the synthesis of organic molecules in the laboratory and industry. Aerobic oxidation methods have long been sought for these transformations, but few practical methods exist that offer advantages over traditional oxidation methods. Recently developed homogeneous Cu/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidinyl-N-oxyl) and related catalyst systems appear to fill this void. The reactions exhibit high levels of chemoselectivity and broad functional-group tolerance, and they often operate efficiently at room temperature with ambient air as the oxidant. These advances, together with their historical context and recent applications, are highlighted in this Minireview. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Di(1-benzo[][1,2,3]triazol-1-yl)methane: An efficient ligand for copper and amine-free palladium-catalysed Sonogashira coupling reaction

    Indian Academy of Sciences (India)

    Jaspal Singh; Akhilesh Kumar Verma

    2011-11-01

    An efficient Pd-catalysed Sonogashira coupling reaction was achieved in the absence of copper and amine with inorganic base using phosphene-free, air stable di(1-benzo[][1,2,3]triazol-1-yl)methane as ligand. The cross coupling of electron-rich, electron-defficient and hindered aryl halides with terminal alkynes afforded the internal alkynes in good to excellent yields.

  6. H2O2-reactivity of copper(II) complexes supported by tris[(pyridin-2-yl)methyl]amine ligands with 6-phenyl substituents.

    Science.gov (United States)

    Kunishita, Atsushi; Kubo, Minoru; Ishimaru, Hirohito; Ogura, Takashi; Sugimoto, Hideki; Itoh, Shinobu

    2008-12-15

    The structure and H(2)O(2)-reactivity of a series of copper(II) complexes supported by tris[(pyridin-2-yl)methyl]amine (TPA) derivatives having a phenyl group at the 6-position of pyridine donor group(s) [(6-phenylpyridin-2-yl)methyl]bis[(pyridin-2-yl)methyl]amine (Ph(1)TPA), bis[(6-phenylpyridin-2-yl)methyl][(pyridin-2-yl)methyl]amine (Ph(2)TPA), and tris[(6-phenylpyridin-2-yl)methyl]amine (Ph(3)TPA) have systematically been examined to get insights into the aromatic substituent (6-Ph) effects on the coordination chemistry of TPA ligand system. The X-ray crystallographic analyses have revealed that [Cu(II)(TPA)(CH(3)CN)](ClO(4))(2) (CuTPA) and [Cu(II)(Ph(3)TPA)(CH(3)CN)](ClO(4))(2) (3) exhibit a trigonal bipyramidal structure, whereas [Cu(II)(Ph(1)TPA)(CH(3)CN)](ClO(4))(2) (1) shows a slightly distorted square pyramidal structure and [Cu(II)(Ph(2)TPA)(CH(3)CN)](ClO(4))(2) (2) has an intermediate structure between trigonal bipyramidal and square pyramidal. On the other hand, the UV-vis and ESR data have suggested that all the copper(II) complexes have a similar trigonal bipyramidal structure in solution. The redox potentials of CuTPA, 1, 2, and 3 have been determined as E(1/2) = -0.34, -0.28, -0.16, and -0.04 mV vs Ag/AgNO(3), respectively, demonstrating that introduction of each 6-Ph group causes positive shift of E(1/2) about 0.1 V. Notable difference in H(2)O(2)-reactivity has been found among the copper(II) complexes. Namely, CuTPA and 1 afforded mononuclear copper(II)-hydroperoxo complexes CuTPA-OOH and 1-OOH, respectively, whereas complex 2 provided bis(mu-oxo)dicopper(III) complex 2-oxo. On the other hand, copper(II) complex 3 was reduced to the corresponding copper(I) complex 3(red). On the basis of the H(2)O(2)-reactivity together with the X-ray structures and the redox potentials of the copper(II) complexes, the substituent effects of 6-Ph are discussed in detail.

  7. EPR study of complex formation between copper (II) ions and sympathomimetic amines in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Preoteasa, E.A. [Inst. of Atomic Physics, IFIN, Bucharest (Romania); Duliu, O.G.; Grecu, V.V. [Bucharest, Univ. (Romania). Dept. of Atomic and Nuclear Physics

    1997-07-01

    The complex formation between sympathomimetic amines (SA): adrenaline (AD), noradrenaline (NA), dopamine (DA), ephedrine (ED) and p-tyramine (pTA), and Cu(II) ion in aqueous solution has been studied by X-band EPR at room temperature. Excepting pTA, all investigated SA yielded two types of complexes in different pH domains. All complexes consistent with a ligand fields having a distorted octahedral symmetry, i.e., hexacoordination of Cu(II). The covalence coefficient calculated from the isotropic g and A values has shown strong ionic sigma-type ligand bonds. A structural model with the Cu(II) ion bound by four catecholic O(hydroxy) atoms for the low pH complexes of AD, NA and DA is proposed. For the high pH complexes of the former compounds as well as for both Ed complexes, the authors suppose Cu(II) bound by two N (amino) and two O (hydroxy) atoms. The spectra are consistent to water binding on the longitudinal octahedron axis in all compounds excepting the high pH complex of Ed, where OH2- ions are bound. Possible implications for the SA-cell receptors interactions are discussed.

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

    Science.gov (United States)

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

    2014-11-01

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

  9. Synthesis and structure of copper(II) complexes: Potential cyanide sensor and oxidase model'

    Indian Academy of Sciences (India)

    PALASH MONDAL; SANKAR PRASAD PARUA; POULAMI PATTANAYAK; UTTAM DAS; SURAJIT CHATTOPADHYAY

    2016-05-01

    The new complexes of compositions $[(L_{a})_{2}Cu]$ and $[(L_{b})_{2}Cu]$ were prepared by treating with2-hydroxy-5-methyl-3-(2-aryldiazenyl)phenylimino) methyl) benzaldehyde $(HL_{a})$ and ethyl-2-cyano-3-(2-hydroxy-5-methyl-3-(-(2-aryldiazenyl) phenylimino) methyl) phenyl) acrylate $(HL_{b})$ ligands [where aryl isphenyl for $HL_{a}^{1}$ and $HL_{b}^{1}$ ; p-methyl phenyl for $HL_{a}^{2}$ and $HL_{b}^{2}$ ; and p-chloro phenyl for $HL_{a}^{3}$ and $HL_{b}^{3}$ ] with $Cu(OAc)_{2}.H_{2}O$, respectively. Both the bis copper(II) complexes consist of tridentate (N,N,O) anionic ligands, $L^{-}_a$ or $L^{-}_b$ . X-ray structures of the representative complexes $[(L^{1}_{a})_{2}Cu]$ and $[(L^{2}_{b})_{2}Cu]$ were determined toconfirm the molecular species unequivocally. The molecular structure of copper complexes exhibited tetragonallydistorted (Jahn-Teller) geometry consistent with the $d^{9}$ configuration of Cu(II) metal ion. Oxidation ofbenzyl alcohols using the newly synthesized complexes as catalyst has been studied. Photoluminescence propertiesof $[(L^{2}_{a})_{2}Cu]$ and $[(L^{2}_{b})_{2}Cu]$ were exploited for selective cyanide recognition. The $[(L_{b})_{2}Cu], complexesdisplayed antibacterial activity toward gram positive and gram negative bacteria

  10. Synthetic heme/copper assemblies: toward an understanding of cytochrome c oxidase interactions with dioxygen and nitrogen oxides.

    Science.gov (United States)

    Hematian, Shabnam; Garcia-Bosch, Isaac; Karlin, Kenneth D

    2015-08-18

    Our long-time niche in synthetic biological inorganic chemistry has been to design ligands and generate coordination complexes of copper or iron ions or both, those reacting with dioxygen (O2) or nitrogen oxides (e.g., nitric oxide (NO(g)) and nitrite (NO2(-))) or both. As inspiration for this work, we turn to mitochondrial cytochrome c oxidase, which is responsible for dioxygen consumption and is also the predominant target for NO(g) and nitrite within mitochondria. In this Account, we highlight recent advances in studying synthetic heme/Cu complexes in two respects. First, there is the design, synthesis, and characterization of new O2 adducts whose further study will add insights into O2 reductive cleavage chemistry. Second, we describe how related heme/Cu constructs reduce nitrite ion to NO(g) or the reverse, oxidize NO(g) to nitrite. The reactions of nitrogen oxides occur as part of CcO's function, which is intimately tied to cellular O2 balance. We had first discovered that reduced heme/Cu compounds react with O2 giving μ-oxo heme-Fe(III)-O-Cu(II)(L) products; their properties are discussed. The O-atom is derived from dioxygen, and interrogations of these systems led to the construction and characterization of three distinctive classes of heme-peroxo complexes, two high-spin and one low-spin species. Recent investigations include a new approach to the synthesis of low-spin heme-peroxo-Cu complexes, employing a "naked" synthon, where the copper ligand denticity and geometric types can be varied. The result is a collection of such complexes; spectroscopic and structural features (by DFT calculations) are described. Some of these compounds are reactive toward reductants/protons effecting subsequent O-O cleavage. This points to how subtle improvements in ligand environment lead to a desired local structure and resulting optimized reactivity, as known to occur at enzyme active sites. The other sector of research is focused on heme/Cu assemblies mediating the redox

  11. Tyrosinase and catechol oxidase activity of copper(I) complexes supported by imidazole-based ligands: structure-reactivity correlations.

    Science.gov (United States)

    Wendt, Franziska; Näther, Christian; Tuczek, Felix

    2016-09-01

    Four new imidazole-based ligands, 4-((1H-imidazol-4-yl)methyl)-2-phenyl-4,5-dihydrooxyzole (L OL 1), 4-((1H-imidazol-4-yl)methyl)-2-(tert-butyl)-4,5-dihydrooxyzole (L OL 2), 4-((1H-imidazol-4-yl)methyl)-2-methyl-4,5-dihydrooxyzole (L OL 3), and N-(2,2-dimethylpropylidene)-2-(1-trityl-1H-imidazol-4-yl-)ethyl amine (L imz 1), have been synthesized. The corresponding copper(I) complexes [Cu(I)(L OL 1)(CH3CN)]PF6 (CuL OL 1), [Cu(I)(L OL 2)(CH3CN)]PF6 (CuL OL 2), [Cu(I)(L OL 3)(CH3CN)]PF6 (CuL OL 3), [Cu(I)(L imz 1)(CH3CN)2]PF6 (CuL imz 1) as well as the Cu(I) complex derived from the known ligand bis(1-methylimidazol-2-yl)methane (BIMZ), [Cu(I)(BIMZ)(CH3CN)]PF6 (CuBIMZ), are screened as catalysts for the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC-H2) to 3,5-di-tert-butylquinone (3,5-DTBQ). The primary reaction product of these oxidations is 3,5-di-tert-butylsemiquinone (3,5-DTBSQ) which slowly converts to 3,5-DTBQ. Saturation kinetic studies reveal a trend of catalytic activity in the order CuL OL 3 ≈ CuL OL 1 > CuBIMZ > CuL OL 2 > CuL imz 1. Additionally, the catalytic activity of the copper(I) complexes towards the oxygenation of monophenols is investigated. As substrates 2,4-di-tert-butylphenol (2,4-DTBP-H), 3-tert-butylphenol (3-TBP-H), 4-methoxyphenol (4-MeOP-H), N-acetyl-L-tyrosine ethyl ester monohydrate (NATEE) and 8-hydroxyquinoline are employed. The oxygenation products are identified and characterized with the help of UV/Vis and NMR spectroscopy, mass spectrometry, and fluorescence measurements. Whereas the copper complexes with ligands containing combinations of imidazole and imine functions or two imidazole units (CuL imz 1 and CuBIMZ) are found to exhibit catalytic tyrosinase activity, the systems with ligands containing oxazoline just mediate a stoichiometric conversion. Correlations between the structures of the complexes and their reactivities are discussed.

  12. 传统中式香肠中产生物胺氧化酶菌的分离鉴定%Separation and Identification of the Biogenic Amines-oxidase Productive Strains in Traditional Chinese Sausage

    Institute of Scientific and Technical Information of China (English)

    邓红梅; 卢士玲; 李开雄

    2012-01-01

    In this study, the method of medium color and oxidase test were used to initially separate the biogenic amines-oxidase productive strains in the fermented sausages. According to the standard of meat fermentation starter culture, we removed the bacteria which did not meet the requirements. For those strains meet the requirements, highperformance liquid was used to detect the ability of oxidation and reduction biogenic amines. Finally, through the comparative 16S rDNA sequences analysis and phylogenetic analysis, we found 4 biogenic amines-oxidase productive strains which meet the fermentation starter culture requirements, one Staphylococcus epidermidis and three Staphylococcus simulans.%结合培养基显色法和氧化酶试验,对发酵香肠中产生物胺氧化酶优势菌进行了初步分离。进而利用肉品发酵剂标准剔除不符合要求的菌株。利用高效液相色谱检测符合要求的产生物胺氧化酶菌株对生物胺的氧化减少能力。最后采用16SrDNA分子鉴定方法,通过同源性比对,得到4株符合发酵剂标准的产生物胺氧化酶菌株,即1株表皮葡萄球菌,3株模仿葡萄球菌。

  13. Interaction with DNA and different effect on the nucleus of cancer cells for copper(II) complexes of N-benzyl di(pyridylmethyl)amine.

    Science.gov (United States)

    Chen, Qiu-Yun; Fu, Hai-Jian; Zhu, Wei-Hua; Qi, Yan; Ma, Zheng-Ping; Zhao, Kai-Di; Gao, Jing

    2011-05-01

    Three new copper(II) complexes of N-benzyl di(pyridylmethyl)amine (phdpa) were synthesized and characterized by spectroscopic methods. The interaction between CT-DNA and the complexes was studied by UV and fluorescence titration methods. It was found that the complex [(phdpa)Cu(H(2)O)Ac)](Ac), with the non-planar aromatic heterocyclic ring ligand (phdpa), showed good anticancer properties and could cause the fragmentation of the nucleus, although its interaction with CT-DNA was weaker than that of 1,10-phenanthroline (phen)-based copper(II) complexes. The anticancer activities of copper(II) complexes with phdpa and phen based ligands are correlated to their binding constants with DNA, but phen-based copper(II) complexes did not cause the nucleus fragmentation of HeLa cells. [(phdpa)Cu(H(2)O)Ac)](Ac) can noticeably decrease the oxygen content of a culture solution and of HeLa cells, which make it a new nucleus and oxygen related anticancer copper(II) complex. Information obtained here would be helpful in the design of new antitumor complexes in oxidative therapy.

  14. (Pentane-2,4-dionato-κ2O,O')(pyridin-2-amine-κN1)copper(II) and (pentane-2,4-dionato-κ2O,O')(pyrimidin-2-amine-κN1)copper(II).

    Science.gov (United States)

    Perdih, Franc

    2012-03-01

    The title compounds, [Cu(C(5)H(7)O(2))(2)(C(5)H(6)N(2))], (I), and [Cu(C(5)H(7)O(2))(2)(C(4)H(5)N(3))], (II), were prepared by the reaction of bis(pentane-2,4-dionato-κ(2)O,O')copper(II) with pyridin-2-amine and pyrimidin-2-amine, respectively. From a chemical point of view, it is interesting that no Schiff base formation was observed. The compounds are isostructural, with both having a square-pyramidal coordination of the Cu(II) atom and intramolecular N-H...O hydrogen bonding. The additional N atom of the pyrimidin-2-amine ligand is not involved in hydrogen bonding or in metal coordination. In the crystal structure, chelate rings are involved in π-π interactions and molecules of (I) are linked together via N-H...O hydrogen bonds.

  15. A versatile and efficient markerless gene disruption system for Acidithiobacillus thiooxidans: application for characterizing a copper tolerance related multicopper oxidase gene.

    Science.gov (United States)

    Wen, Qing; Liu, Xiangmei; Wang, Huiyan; Lin, Jianqun

    2014-11-01

    The acidophilic bioleaching bacteria can usually survive in high concentrations of copper ions because of their special living environment. However, little is known about the copper homeostatic mechanisms of Acidithiobacillus thiooxidans, an important member of bioleaching bacteria. Here, a putative multicopper oxidase gene (cueO) was detected from the draft genome of A. thiooxidans ATCC 19377. The transcriptional level of cueO in response to 10 mM CuSO₄was upregulated 25.01 ± 2.59 folds. The response of P(cueO) to copper was also detected and might be stimulated by a putative CueR protein. Then, by using the counter-selectable marker lacZ and enhancing the expression of endonuclease I-SceI with tac promoter, a modified markerless gene disruption system was developed and the cueO gene disruption mutant (ΔcueO) of A. thiooxidans was successfully constructed with a markedly improved second homologous recombination frequency of 0.28 ± 0.048. The ΔcueO mutant was more sensitive to external copper and nearly completely lost the phenoloxidase activity; however, the activity could be restored after complementing the cueO gene. All results suggest the close relation of cueO gene to copper tolerance in A. thiooxidans. In addition, the developed efficient markerless gene knockout method can also be introduced into other Acidithiobacillus strains.

  16. Syntheses and structures of closely related copper(I) complexes of tridentate (2-pyridylmethyl)imine and (2-pyridylmethyl)amine ligands and their use in mediating atom transfer radical polymerizations.

    Science.gov (United States)

    Turner, Sara A; Remillard, Zachary D; Gijima, Desire T; Gao, Emily; Pike, Robert D; Goh, Christopher

    2012-10-15

    A series of five copper(I) bromide complexes of tridentate (N,N,L) pyridine-imine and pyridine-amine ligands with a third amine, ether, or thioether neutral donor was synthesized and utilized in the atom transfer radical polymerization of styrene. The ligand design illustrated a systematic approach to the development of copper complexes for use in ATRP. Variations in the nature of the ligand impacted the solid state structures of the complexes. A mononuclear [CuBr(L)] complex was observed for L = pyridine-amine-amine, whereas complexes of L = pyridine-imine-amine and -thioether formed dinuclear [CuBr(L)](2) structures with a central 10-membered ring. A doubly-bromide-bridged dimer was revealed for the [CuBr(L)] complex of L = pyridine-imine-ether and a polymeric species for [CuBr(L)], where L = pyridine-imine-amine and the imine-amine spacer was extended from two to three carbon atoms. In the application of these complexes to the ATRP of styrene, the redox potentials of the complexes were found to be one indicator of ATRP efficiency. Of the series presented, two complexes in particular provided fast polymerization rates and good to excellent molecular weight control. In both of these complexes, the ligand contained all nitrogen-based donor moieties.

  17. 纳米氧化铜催化碘代芳烃的氨基化反应%Ligand-free copper(Ⅱ)-catalyzed amination of aryl iodides

    Institute of Scientific and Technical Information of China (English)

    吕良忠; 徐欢; 丁元华; 刘伟; 袁宇

    2012-01-01

    针对硝基化合物还原制备芳香胺中反应条件苛刻、适用范围较小、副产物较多、产品质量欠佳等缺陷,研究出一种以纳米氧化铜为催化剂、氨水为氨源且无配体参与的一步合成芳香伯胺的方法.该方法具有原料价廉、反应条件温和、对环境友好等优点,为芳香胺的合成增添了新的途径.%Reduction of nitro substituted aromatic compounds is the main method for preparation of aromatic amines in industry at present. However, the conventional synthetic methods often have relatively harsh reaction conditions, small scope of application, unavoidable by-products, poor selectivity, poor product quality and other shortcomings. This paper develops one step method of ligand-free nano copper oxide catalyzed amination reaction of aryl iodides with ammonia. Aqueous NH3 solution is a convenient and inexpensive source of ammonia. The synthesis method with mild conditions and environmental friendliness, has added a new method for synthesizing primary aromatic amines.

  18. Synthesis, magnetostructural correlation, and catalytic promiscuity of unsymmetric dinuclear copper(II) complexes: models for catechol oxidases and hydrolases.

    Science.gov (United States)

    Osório, Renata E H M B; Peralta, Rosely A; Bortoluzzi, Adailton J; de Almeida, Vicente R; Szpoganicz, Bruno; Fischer, Franciele L; Terenzi, Hernán; Mangrich, Antonio S; Mantovani, Karen Mary; Ferreira, Dalva E C; Rocha, Willian R; Haase, Wolfgang; Tomkowicz, Zbigniew; dos Anjos, Ademir; Neves, Ademir

    2012-02-06

    Herein, we report the synthesis and characterization, through elemental analysis, electronic spectroscopy, electrochemistry, potentiometric titration, electron paramagnetic resonance, and magnetochemistry, of two dinuclear copper(II) complexes, using the unsymmetrical ligands N',N',N-tris(2-pyridylmethyl)-N-(2-hydroxy-3,5-di-tert-butylbenzyl)-1,3-propanediamin-2-ol (L1) and N',N'-bis(2-pyridylmethyl)-N,N-(2-hydroxybenzyl)(2-hydroxy-3,5-di-tert-butylbenzyl)-1,3-propanediamin-2-ol (L2). The structures of the complexes [Cu(2)(L1)(μ-OAc)](ClO(4))(2)·(CH(3))(2)CHOH (1) and [Cu(2)(L2)(μ-OAc)](ClO(4))·H(2)O·(CH(3))(2)CHOH (2) were determined by X-ray crystallography. The complex [Cu(2)(L3)(μ-OAc)](2+) [3; L3 = N-(2-hydroxybenzyl)-N',N',N-tris(2-pyridylmethyl)-1,3-propanediamin-2-ol] was included in this study for comparison purposes only (Neves et al. Inorg. Chim. Acta2005, 358, 1807-1822). Magnetic data show that the Cu(II) centers in 1 and 2 are antiferromagnetically coupled and that the difference in the exchange coupling J found for these complexes (J = -4.3 cm(-1) for 1 and J = -40.0 cm(-1) for 2) is a function of the Cu-O-Cu bridging angle. In addition, 1 and 2 were tested as catalysts in the oxidation of the model substrate 3,5-di-tert-butylcatechol and can be considered as functional models for catechol oxidase. Because these complexes possess labile sites in their structures and in solution they have a potential nucleophile constituted by a terminal Cu(II)-bound hydroxo group, their activity toward hydrolysis of the model substrate 2,4-bis(dinitrophenyl)phosphate and DNA was also investigated. Double electrophilic activation of the phosphodiester by monodentate coordination to the Cu(II) center that contains the phenol group with tert-butyl substituents and hydrogen bonding of the protonated phenol with the phosphate O atom are proposed to increase the hydrolase activity (K(ass.) and k(cat.)) of 1 and 2 in comparison with that found for complex 3. In fact

  19. Designed copper-amine complex as an efficient template for one-pot synthesis of Cu-SSZ-13 zeolite with excellent activity for selective catalytic reduction of NOx by NH3.

    Science.gov (United States)

    Ren, Limin; Zhu, Longfeng; Yang, Chengguang; Chen, Yanmei; Sun, Qi; Zhang, Haiyan; Li, Caijin; Nawaz, Faisal; Meng, Xiangju; Xiao, Feng-Shou

    2011-09-21

    Low-cost copper-amine complex was rationally designed to be a novel template for one-pot synthesis of Cu-SSZ-13 zeolites. Proper confirmation and appropriate size make this complex fit well with CHA cages as an efficient template. The products exhibit superior catalytic performance on NH(3)-SCR reaction.

  20. Diversity-oriented approach to 1,2-dihydroisoquinolin-3(4H)-imines via copper(I)-catalyzed reaction of (E)-2-ethynylphenylchalcone, sulfonyl azide and amine.

    Science.gov (United States)

    Chen, Zhiyuan; Ye, Chao; Gao, Liang; Wu, Jie

    2011-05-21

    A three-component reaction of (E)-2-ethynylphenylchalcone, sulfonyl azide, and amine catalyzed by copper(I) chloride (5 mol%), in the presence of triethylamine, under mild conditions is described. This transformation proceeds efficiently to generate 1,2-dihydroisoquinolin-3(4H)-imines in good to excellent yields. © The Royal Society of Chemistry 2011

  1. μ-Cyanido-κ(2) C:N-dicyanido-κ(2) C-bis-(N-ethyl-ethylenedi-amine-κ(2) N,N')copper(II)copper(I).

    Science.gov (United States)

    Corfield, Peter W R; Michalski, Joseph F

    2014-02-01

    In the title complex, [Cu(I)Cu(II)(CN)3(C4H12N2)2], the Cu(I) and Cu(II) ions and a bridging cyanide group lie on a twofold rotation axis. The Cu(II) ion is in a slightly-distorted square-pyramidal coordination environment, with the N atoms of the two symmetry-related N-ethyl-ethylenedi-amine ligands occupying the basal positions and an N-bonded cyanide group in the apical position. The Cu(I) ion is in a trigonal-planar coordination environment, bonded to the C atom of the bridging cyanide group and to two terminal cyanide groups. In the crystal, N-H⋯N hydrogen bonds involving two of the symmetry-unique N-H groups of the N-ethyl-ethylenedi-amine ligands and the N atoms of the terminal cyanide ligands link the mol-ecules into strands along [010].

  2. Characterization of a Highly Thermostable and Organic Solvent-Tolerant Copper-Containing Polyphenol Oxidase with Dye-Decolorizing Ability from Kurthia huakuii LAM0618T.

    Science.gov (United States)

    Guo, Xiang; Zhou, Shan; Wang, Yanwei; Song, Jinlong; Wang, Huimin; Kong, Delong; Zhu, Jie; Dong, Weiwei; He, Mingxiong; Hu, Guoquan; Ruan, Zhiyong

    2016-01-01

    Laccases are green biocatalysts that possess attractive advantages for the treatment of resistant environmental pollutants and dye effluents. A putative laccase-like gene, laclK, encoding a protein of 29.3 kDa and belonging to the Cu-oxidase_4 superfamily, was cloned and overexpressed in Escherichia coli. The purified recombinant protein LaclK (LaclK) was able to oxidize typical laccase substrates such as 2,6-dimethoxyphenol and l-dopamine. The characteristic adsorption maximums of typical laccases at 330 nm and 610 nm were not detected for LaclK. Cu2+ was essential for substrate oxidation, but the ratio of copper atoms/molecule of LaclK was determined to only be 1:1. Notably, the optimal temperature of LaclK was 85°C with 2,6-dimethoxyphenol as substrates, and the half-life approximately 3 days at 80°C. Furthermore, 10% (v/v) organic solvents (methanol, ethanol, isopropyl alcohol, butyl alcohol, Triton x-100 or dimethyl sulfoxide) could promote enzymatic activity. LaclK exhibited wide-spectrum decolorization ability towards triphenylmethane dyes, azo dyes and aromatic dyes, decolorizing 92% and 94% of Victoria Blue B (25 μM) and Ethyl Violet (25 μM), respectively, at a concentration of 60 U/L after 1 h of incubation at 60°C. Overall, we characterized a novel thermostable and organic solvent-tolerant copper-containing polyphenol oxidase possessing dye-decolorizing ability. These unusual properties make LaclK an alternative for industrial applications, particularly processes that require high-temperature conditions.

  3. Characterization of a Highly Thermostable and Organic Solvent-Tolerant Copper-Containing Polyphenol Oxidase with Dye-Decolorizing Ability from Kurthia huakuii LAM0618T

    Science.gov (United States)

    Guo, Xiang; Zhou, Shan; Wang, Yanwei; Song, Jinlong; Wang, Huimin; Kong, Delong; Zhu, Jie; Dong, Weiwei; He, Mingxiong; Hu, Guoquan; Ruan, Zhiyong

    2016-01-01

    Laccases are green biocatalysts that possess attractive advantages for the treatment of resistant environmental pollutants and dye effluents. A putative laccase-like gene, laclK, encoding a protein of 29.3 kDa and belonging to the Cu-oxidase_4 superfamily, was cloned and overexpressed in Escherichia coli. The purified recombinant protein LaclK (LaclK) was able to oxidize typical laccase substrates such as 2,6-dimethoxyphenol and l-dopamine. The characteristic adsorption maximums of typical laccases at 330 nm and 610 nm were not detected for LaclK. Cu2+ was essential for substrate oxidation, but the ratio of copper atoms/molecule of LaclK was determined to only be 1:1. Notably, the optimal temperature of LaclK was 85°C with 2,6-dimethoxyphenol as substrates, and the half-life approximately 3 days at 80°C. Furthermore, 10% (v/v) organic solvents (methanol, ethanol, isopropyl alcohol, butyl alcohol, Triton x-100 or dimethyl sulfoxide) could promote enzymatic activity. LaclK exhibited wide-spectrum decolorization ability towards triphenylmethane dyes, azo dyes and aromatic dyes, decolorizing 92% and 94% of Victoria Blue B (25 μM) and Ethyl Violet (25 μM), respectively, at a concentration of 60 U/L after 1 h of incubation at 60°C. Overall, we characterized a novel thermostable and organic solvent-tolerant copper-containing polyphenol oxidase possessing dye-decolorizing ability. These unusual properties make LaclK an alternative for industrial applications, particularly processes that require high-temperature conditions. PMID:27741324

  4. Substituted tren-capped porphyrins: probing the influence of copper in synthetic models of cytochrome c oxidase.

    Science.gov (United States)

    Didier, Amandine; L'Her, Maurice; Boitrel, Bernard

    2003-04-21

    Tris(2-aminoethylamine) (tren)-capped porphyrins bearing electron donating or withdrawing groups on the amino functions of their tripod have been synthesised and the catalytic activity of each complex was carefully studied both as the iron and the iron-copper complexes: only one of our iron-copper complexes was shown to be active and selective towards the reduction of dioxygen to water.

  5. Crystal Structure and Inhibitory Activity against Xanthine Oxidase of Bis(μ2-chloro)-chloro-(μ-N,N'-(2-pyridylmethylene)Furanmethanoamine Copper(Ⅱ)Complex

    Institute of Scientific and Technical Information of China (English)

    FANG Rui-Qin; SHI Da-Hua; SHI Lei; ZHU Hai-Liang

    2008-01-01

    A chloro-bridged dinuclear copper(Ⅱ) complex with ligand 2-pyridylme-thylene-furfurylamine has been synthesized and characterized by single-crystal X-ray diffraction,and its inhibitory activity on xanthine oxidase(XO)Was also evaluated.It crystallizes in the triclinic system,space group P-1 with a=8.0441(16),b=8.5663(17),c=10.060(2)(A),α=77.52(3),β=72.04(3),γ=70.12(3)°,V=615.3(2)(A)3,Z=1,Dc=1.731 g/cm3,F(000)=322,the final R=0.0401 and wR=0.0934 for 1971 observed reflections with Ⅰ>2σ(Ⅰ).X-ray analysis reveals that the Cu(Ⅱ)cation is five-coordinated by two N atoms of Schiff base and three C1 anions.The C-H…Cl intermolecular and intramolecular hydrogen bonds connect the molecules to form a three-dimensional network.Tilis copper(Ⅱ) complex shows more potent inhibitory activity against XO with Ⅰ C50=3.48/μM than the standard inhibitor allopurinol.

  6. An unexpected copper catalyzed ‘reduction’ of an arylazide to amine through the formation of a nitrene intermediate

    Science.gov (United States)

    Draganov, Alexander B.; Chen, Weixuan; Dai, Chaofeng; Nelson, William H.; Liu, Aimin; Wang, Binghe

    2013-01-01

    Azido nitrobenzoxadiazole (NBD) was observed to undergo a ‘reduction’ reaction in the absence of an obvious reducing agent, leading to amine formation. In the presence of an excess amount of DMSO, a sulfoxide conjugate was also formed. The ratio of these two products was both temperature- and solvent-dependent, with the addition of water significantly enhancing the ratio of the ‘reduction’ product. Two intermediates of the azido-NBD reaction in DMSO were trapped and characterized by low-temperature EPR spectroscopy. One was an organic free radical (S=1/2) and another was a triplet nitrene (S=1) species. A mechanism was proposed based on the characterized free radical and triplet intermediates. PMID:23997313

  7. Determination of human serum semicarbazide-sensitive amine oxidase activity via flow injection analysis with fluorescence detection after online derivatization of the enzymatically produced benzaldehyde with 1,2-diaminoanthraquinone.

    Science.gov (United States)

    El-Maghrabey, Mahmoud H; Kishikawa, Naoya; Ohyama, Kaname; Imazato, Takahiro; Ueki, Yukitaka; Kuroda, Naotaka

    2015-06-30

    A fast, simple, and sensitive flow injection analysis method was developed for the measurement of semicarbazide-sensitive amine oxidase (SSAO) activity in human serum. Benzaldehyde, generated by the action of SSAO after incubation of serum with benzylamine, was derivatized with a novel aromatic aldehyde-specific reagent (1,2-diaminoanthraquinone) and the fluorescent product was measured by fluorescence detection at excitation and emission wavelengths of 390 and 570nm, respectively. Serum SSAO activity was defined as benzaldehyde (nmol) formed per milliliter serum per hour. The method was linear over SSAO activity of 0.2-150.0nmolmL(-1)h(-1) with a detection limit of 0.06nmolmL(-1)h(-1). The %RSD of intra-day and inter-day precision did not exceed 9.4% and the accuracy ranged from -6.5 to -0.6%. The method was applied for the determination of the serum SSAO activity in healthy controls (C, n=24) and diabetes mellitus patients (DM, n=18). It was demonstrated that the activity (mean±SE) of SSAO in diabetics sera was significantly higher than that in healthy subjects' ones (DM; 73.3±1.8nmolmL(-1)h(-1)vs C; 58.9±2.2nmolmL(-1)h(-1), P<0.01).

  8. Bimodal-hybrid heterocyclic amine targeting oxidative pathways and copper mis-regulation in Alzheimer’s disease

    Science.gov (United States)

    Gonzalez, Paulina; da Costa, Viviana C.P.; Hyde, Kimberly; Wu, Qiong; Annunziata, Onofrio; Rizo, Josep; Akkaraju, Giridhar; Green, Kayla N.

    2014-01-01

    Oxidative stress resulting from metal-ion misregulation plays a role in the development of Alzheimer’s disease (AD). This process includes the production of tissue-damaging reactive oxygen species and amyloid aggregates. Herein we describe the synthesis, characterization and protective capacity of the small molecule, lipoic cyclen, which has been designed to target molecular features of AD. This construct utilizes the biologically compatible and naturally occurring lipoic acid as a foundation for engendering low cellular toxicity in multiple cell lines, radical scavenging capacity, tuning the metal affinity of the parent cyclen, and results in an unexpected affinity for amyloid without inducing aggregation. The hybrid construct thereby shows protection against cell death induced by amyloid aggregates and copper ions. These results provide evidence for the rational design methods used to produce this fused molecule as a potential strategy for the development of lead compounds for the treatment of neurodegenerative disorders. PMID:25144522

  9. [Serum cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE ) and cytochrome c oxidase (COX) in copper mine miners potentially expose d to hydrogen sulfide].

    Science.gov (United States)

    Skoczyńska, Anna; Gruszczyński, Leszek; Turczyn, Barbara; Ścieszka, Marek; Wojakowska, Anna; Pawłowski, Tomasz; Schmidt, Edward

    2015-01-01

    The aim of the study was to evaluate serum levels of the target enzyme for H2S toxicity--cytochrome c oxidase (COX) and enzymes involved in the synthesis of H2S--cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) in copper mine miners. The initial and basic study was conducted respectively in 237 and 88 miners, working in 2 mining shafts: I--no H2S emissions recorded in the last 10 years (study group A) and II--H2S emissions occurred (study group B). A medical examination was performed and 10 ml of blood was collected from miners immediately after exiting the mine. There were no clinical or biochemical changes typical for H2S toxicity. Sulfhemoglobine was undetectable and there were no changes in the red-ox system. However, in group B, regulatory changes were found; a tendency to higher concentration of CBS and CSE, a higher activity of angiotensin converting enzyme (ACE) compared to group A (pCBS and CSE activity. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  10. Modifications on the hydrogen bond network by mutations of Escherichia coli copper efflux oxidase affect the process of proton transfer to dioxygen leading to alterations of enzymatic activities

    Energy Technology Data Exchange (ETDEWEB)

    Kajikawa, Takao; Kataoka, Kunishige [Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192 (Japan); Sakurai, Takeshi, E-mail: tsakurai@se.kanazawa-u.ac.jp [Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192 (Japan)

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Proton transfer pathway to dioxygen in CueO was identified. Black-Right-Pointing-Pointer Glu506 is the key amino acid to transport proton. Black-Right-Pointing-Pointer The Ala mutation at Glu506 formed a compensatory proton transfer pathway. Black-Right-Pointing-Pointer The Ile mutation at Glu506 shut down the hydrogen bond network. -- Abstract: CueO has a branched hydrogen bond network leading from the exterior of the protein molecule to the trinuclear copper center. This network transports protons in the four-electron reduction of dioxygen. We replaced the acidic Glu506 and Asp507 residues with the charged and uncharged amino acid residues. Peculiar changes in the enzyme activity of the mutants relative to the native enzyme indicate that an acidic amino acid residue at position 506 is essential for effective proton transport. The Ala mutation resulted in the formation of a compensatory hydrogen bond network with one or two extra water molecules. On the other hand, the Ile mutation resulted in the complete shutdown of the hydrogen bond network leading to loss of enzymatic activities of CueO. In contrast, the hydrogen bond network without the proton transport function was constructed by the Gln mutation. These results exerted on the hydrogen bond network in CueO are discussed in comparison with proton transfers in cytochrome oxidase.

  11. Synthesis, Characterization of Heterodinuclear Co-Cu Complex and Its Electrocatalytic Activity towards 02 Reduction: Implications for Cytochrome c Oxidase Active Site Modeling

    Institute of Scientific and Technical Information of China (English)

    卢卫兵; 汪存信; 周晓海; 任建国

    2003-01-01

    A new dinudeating ligand consisting of a tetraphanylporphyrin derivative covalently linked with tris(2-benzimidazylmethyl)-amine and its homodinudear Co-Co and heterodinnelear Co-Cu complexes were synthesized and spectroscopically character-ized. The heterobimetallie cobalt-copper complex bearing three benzimidazole ligands for copper, as cytochrome c oxidase ac-tive site model, was applied to the surface of glassy carbon elec-trode to show electrocatalytie activity for O2 reduction in aque-ous solution at an addity level dose to physiological pH value.The kinetic parameters of this electrocatalytic process were ob-tained.

  12. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis

    NARCIS (Netherlands)

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

    2014-01-01

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

  13. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis

    NARCIS (Netherlands)

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

    2014-01-01

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

  14. EFFECTS OF HYDRAZINES ON THE METABOLISM OF CERTAIN AMINES AND AMINO ACIDS.

    Science.gov (United States)

    AMINES, * AMINO ACIDS , *DIAMINE OXIDASE, TOXICITY, METABOLISM, METABOLISM, DIMETHYLHYDRAZINES, GLUTAMIC ACID, ENZYMES, PHARMACOLOGY, TRACER STUDIES, LABELED SUBSTANCES, RESPIRATION, GASTROINTESTINAL SYSTEM, RATS.

  15. Serum cystathionine β-synthase (CBS, cystathionine γ-lyase (CSE and cytochrome c oxidase (COX in copper mine miners potentially expose d to hydrogen sulfide

    Directory of Open Access Journals (Sweden)

    Anna Skoczyńska

    2015-08-01

    Full Text Available Background: The aim of the study was to evaluate serum levels of the target enzyme for H2S toxicity – cytochrome c oxidase (COX and enzymes involved in the synthesis of H2S – cystathionine β-synthase (CBS and cystathionine γ-lyase (CSE in copper mine miners. Material and Methods: The initial and basic study was conducted respectively in 237 and 88 miners, working in 2 mining shafts: I – no H2S emissions recorded in the last 10 years (study group A and II – H2S emissions occurred (study group B. A medical examination was performed and 10 ml of blood was collected from miners immediately after exiting the mine. Results: There were no clinical or biochemical changes typical for H2S toxicity. Sulfhemoglobine was undetectable and there were no changes in the red-ox system. However, in group B, regulatory changes were found; a tendency to higher concentration of CBS and CSE, a higher activity of angiotensin converting enzyme (ACE compared to group A (p < 0.05 and a linear relationship between ACE and CSE (r = 0.6927; p < 0.001. It has been shown that cigarette smoking decreases COX (p < 0.05, however, in miners working in shaft II, the decreased level of COX may result also from the presence of H2S in the gaseous emissions. Conclusions: COX concentration can be a sensitive indicator of exposure to H2S. The measurements of blood H2S concentrations carried out in workplaces should explain the cause of the changes observed in the COX, CBS and CSE activity. Med Pr 2015;66(4:539–548

  16. 含芳胺及二肽的铜(Ⅱ)配合物的结构及其应用%Structures and Application of Copper(Ⅱ) Complexes Containing Aromatic Amines and Dipeptides

    Institute of Scientific and Technical Information of China (English)

    傅夏兵; 林子华; 乐学义

    2013-01-01

    Broad interests are attracted by ternary copper (Ⅱ) complexes with aromatic amines and dipeptides, since the complexes with considerable DNA-cleavage, SOD and antitumor activity can be used as chemical nucleases, SOD mimics and cancer chemotherapy drugs. This paper makes a summarization about the recent research progress from domestic and overseas in copper(Ⅱ) complexes containing aromatic amine and dipeptide, which focuses chiefly on the structures and applications of this kind of complexes.%含芳胺及二肽的铜(Ⅱ)配合物具有良好的DNA切割活性、SOD活性和抗肿瘤活性,可作化学核酸酶、SOD模拟物及肿瘤化疗药物等应用,因而引起了国内外学者的广泛关注.本文就国内外对含芳胺及二肽的铜(Ⅱ)配合物研究的进展,尤其是该类配合物的结构及其应用作一综述.

  17. Systems Biology Approach in Chlamydomonas Reveals Connections between Copper Nutrition and Multiple Metabolic Steps[C][W][OA

    Science.gov (United States)

    Castruita, Madeli; Casero, David; Karpowicz, Steven J.; Kropat, Janette; Vieler, Astrid; Hsieh, Scott I.; Yan, Weihong; Cokus, Shawn; Loo, Joseph A.; Benning, Christoph; Pellegrini, Matteo; Merchant, Sabeeha S.

    2011-01-01

    In this work, we query the Chlamydomonas reinhardtii copper regulon at a whole-genome level. Our RNA-Seq data simulation and analysis pipeline validated a 2-fold cutoff and 10 RPKM (reads per kilobase of mappable length per million mapped reads) (~1 mRNA per cell) to reveal 63 CRR1 targets plus another 86 copper-responsive genes. Proteomic and immunoblot analyses captured 25% of the corresponding proteins, whose abundance was also dependent on copper nutrition, validating transcriptional regulation as a major control mechanism for copper signaling in Chlamydomonas. The impact of copper deficiency on the expression of several O2-dependent enzymes included steps in lipid modification pathways. Quantitative lipid profiles indicated increased polyunsaturation of fatty acids on thylakoid membrane digalactosyldiglycerides, indicating a global impact of copper deficiency on the photosynthetic apparatus. Discovery of a putative plastid copper chaperone and a membrane protease in the thylakoid suggest a mechanism for blocking copper utilization in the chloroplast. We also found an example of copper sparing in the N assimilation pathway: the replacement of copper amine oxidase by a flavin-dependent backup enzyme. Forty percent of the targets are previously uncharacterized proteins, indicating considerable potential for new discovery in the biology of copper. PMID:21498682

  18. Origin and evolution of lysyl oxidases.

    Science.gov (United States)

    Grau-Bové, Xavier; Ruiz-Trillo, Iñaki; Rodriguez-Pascual, Fernando

    2015-05-29

    Lysyl oxidases (LOX) are copper-dependent enzymes that oxidize primary amine substrates to reactive aldehydes. The best-studied role of LOX enzymes is the remodeling of the extracellular matrix (ECM) in animals by cross-linking collagens and elastin, although intracellular functions have been reported as well. Five different LOX enzymes have been identified in mammals, LOX and LOX-like (LOXL) 1 to 4, showing a highly conserved catalytic carboxy terminal domain and more divergence in the rest of the sequence. Here we have surveyed a wide selection of genomes in order to infer the evolutionary history of LOX. We identified LOX proteins not only in animals, but also in many other eukaryotes, as well as in bacteria and archaea - which reveals a pre-metazoan origin for this gene family. LOX genes expanded during metazoan evolution resulting in two superfamilies, LOXL2/L3/L4 and LOX/L1/L5. Considering the current knowledge on the function of mammalian LOX isoforms in ECM remodeling, we propose that LOXL2/L3/L4 members might have preferentially been involved in making cross-linked collagen IV-based basement membrane, whereas the diversification of LOX/L1/L5 forms contributed to chordate/vertebrate-specific ECM innovations, such as elastin and fibronectin. Our work provides a novel view on the evolution of this family of enzymes.

  19. multicopper oxidases important for human iron metabolism

    Directory of Open Access Journals (Sweden)

    Diana Wierzbicka

    2014-01-01

    Full Text Available Multi-copper oxidases are a group of proteins which demonstrate enzymatic activity and are capable of oxidizing their substrates with the concomitant reduction of dioxygen to two water molecules. For some multi-copper oxidases there has been demonstrated ferroxidase activity which is related to their specific structure characterized by the presence of copper centres and iron-binding sites. Three multi-copper oxidases have been included in this group: ceruloplasmin, hephaestin and zyklopen. Multi copper oxidases which are expressed in different tissues are capable of oxidizing a wide spectrum of substrates. Multi-copper oxidases are capable of oxidizing a wide spectrum of substrates. Ceruloplasmin exhibits antioxidant activity as well as being involved in many other biological processes. The observations of phenotypic effects of absence or low expression of multi-copper ferroxidase-coding genes suggest that the main role of these proteins is taking part in iron metabolism. The main role of ceruloplasmin in iron turnover is oxidizing Fe2+ into Fe3+, a process which is essential for iron binding to transferrin (the main iron-transporting protein, as well as to ferritin (the main iron-storage protein. The function of hephaestin as ferroxidase is essential for iron binding to apotransferrin in the lamina propria of the intestinal mucosa, a process that is important for further transport of iron to the liver by the portal vein. Available data indicate that zyklopen is responsible for the placental iron transport. The presence of three multi-copper oxidases with ferroxidase activity emphasizes the significance of oxidation for iron metabolism. The distribution of multi-copper ferroxidases in many tissues ensures the proper iron turnover in the body as well as preventing toxic effects related to the presence of Fe2+ ions. These ions contribute to generation of free radicals, including the highly reactive hydroxyl radical, through the Fenton and Haber

  20. Pathological changes in platelet histamine oxidases in atopic eczema

    Directory of Open Access Journals (Sweden)

    Reinhold Kiehl

    1993-01-01

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

  1. Tetra-μ-acetato-κ8O:O′-bis{[N-(4-methylphenylpyridin-2-amine-κN1]copper(II}(Cu—Cu

    Directory of Open Access Journals (Sweden)

    Zainal Abidin Fairuz

    2011-11-01

    Full Text Available The complete dinuclear molecule of the title complex, [Cu2(CH3COO4(C12H12N22], is generated by a centre of inversion. The CuII atoms are connected [Cu—Cu = 2.6329 (16 Å] and bridged by four acetate ligands. The distorted octahedral coordination geometry is completed by a terminal pyridine N atom. The amine H atom forms an intramolecular N—H...O hydrogen bond.

  2. A Plasmodium falciparum copper-binding membrane protein with copper transport motifs

    OpenAIRE

    Choveaux David L; Przyborski Jude M; Goldring JP

    2012-01-01

    Abstract Background Copper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper st...

  3. An integrative technique based on synergistic coremoval and sequential recovery of copper and tetracycline with dual-functional chelating resin: roles of amine and carboxyl groups.

    Science.gov (United States)

    Ling, Chen; Liu, Fu-Qiang; Xu, Chao; Chen, Tai-Peng; Li, Ai-Min

    2013-11-27

    A novel chelating resin (R-AC) bearing dual-functional groups (amino and carboxyl groups) was self-synthesized and it showed superior properties on synergistic coremoval of Cu(II) and tetracycline (TC) to commercial resins (amine, carboxyl, and hydrophobic types), which was deeply investigated by equilibrium and kinetic tests in binary, preloading, and saline systems. The adsorption of TC on R-AC was markedly enhanced when coexisted with Cu(II), up to 13 times of that in sole system, whereas Cu(II) uptake seldom decreased in the copresence of TC. Decomplexing-bridging, which included [Cu-TC] decomplexing and [R-Cu] bridging for TC, was demonstrated as the leading mechanism for the synergistic coremoval of Cu(II) and TC. Carboxyl groups of R-AC played a dominant role in decomplexing of [Cu-TC] complex and releasing free TC. Cu(II) coordinated with amine groups of R-AC was further proved to participate in bridging interaction with free TC, and the bridging stoichiometric ratio ([NH-Cu]: TC) possibly was 2:1. About 96.9% of TC and 99.3% of Cu could be sequentially recovered with dilute NaOH followed by HCl. Considering stable application for five cycles in simulated and practical wastewater, R-AC shows great potential in green and simple coremoval of antibiotic and heavy metal ions.

  4. The Potential of the Yeast Debaryomyces hansenii H525 to Degrade Biogenic Amines in Food

    Directory of Open Access Journals (Sweden)

    Mathias Bäumlisberger

    2015-11-01

    Full Text Available Twenty-six yeasts from different genera were investigated for their ability to metabolize biogenic amines. About half of the yeast strains produced one or more different biogenic amines, but some strains of Debaryomyces hansenii and Yarrowia lipolytica were also able to degrade such compounds. The most effective strain D. hanseniii H525 metabolized a broad spectrum of biogenic amines by growing and resting cells. Degradation of biogenic amines by this yeast isolate could be attributed to a peroxisomal amine oxidase activity. Strain H525 may be useful as a starter culture to reduce biogenic amines in fermented food.

  5. [Copper pathology (author's transl)].

    Science.gov (United States)

    Mallet, B; Romette, J; Di Costanzo, J D

    1982-01-30

    Copper is an essential dietary component, being the coenzyme of many enzymes with oxidase activity, e.g. ceruloplasmin, superoxide dismutase, monoamine oxidase, etc. The metabolism of copper is complex and imperfectly known. Active transport of copper through the intestinal epithelial cells involves metallothionein, a protein rich in sulfhydryl groups which also binds the copper in excess and probably prevents absorption in toxic amounts. In hepatocytes a metallothionein facilitates absorption by a similar mechanism and regulates copper distribution in the liver: incorporation in an apoceruloplasmin, storage and synthesis of copper-dependent enzymes. Metallothioneins and ceruloplasmin are essential to adequate copper homeostasis. Apart from genetic disorders, diseases involving copper usually result from hypercupraemia of varied origin. Wilson's disease and Menkes' disease, although clinically and pathogenetically different, are both marked by low ceruloplasmin and copper serum levels. The excessive liver retention of copper in Wilson's disease might be due to increased avidity of hepatic metallothioneins for copper and decreased biliary excretion through lysosomal dysfunction. Menkes' disease might be due to low avidity of intestinal and hepatic metallothioneins for copper. The basic biochemical defect responsible for these two hereditary conditions has not yet been fully elucidated.

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

    CSIR Research Space (South Africa)

    Bannister, M

    2011-04-01

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

  7. Synthesis and characterization of bisoxazolines- and pybox-copper(II) complexes and their application in the coupling of α-carbonyls with functionalized amines

    KAUST Repository

    Jia, Weiguo

    2014-01-01

    Binuclear complexes [{(DMOX)CuCl}2(μ-Cl)2] (1), mononuclear complexes [(DMOX)CuBr2] (2) (DMOX = 4,5-dihydro-2-(4,5- dihydro-4,4-dimethyloxazol-2-yl)-4,4-dimethyloxazole) and the pybox Cu(ii) complex [(Dm-Pybox)CuBr2] (3) (Dm-Pybox = 2,6-bis[4′,4′- dimethyloxazolin-2′-yl]pyridine) were obtained by reactions of CuX 2 (X = Cl, Br) with DMOX and Dm-Pybox ligands, respectively. The molecular structures of 1, 2 and 3 have been determined by single-crystal X-ray diffraction analyses. The complexes 2 and 3 are efficient in catalyzing α-amination of ketones and esters through α-bromo carbonyl intermediate. The procedures are environmentally benign methods using molecular oxygen as an oxidant with water as the only byproduct. This journal is © the Partner Organisations 2014.

  8. The Oxidative Coupling of 2,6-Xylenol Catalyzed by Polymeric Complexes of Copper, 1. Kinetic Study of the Catalysis by Copper(II)-Complexes of Partially Aminated Polystyrene

    NARCIS (Netherlands)

    Schouten, Arend Jan; Prak, Nanno; Challa, Ger

    1977-01-01

    The oxidative coupling reaction of 2,6-xylenol catalyzed by copper(II) complexes of chemically modified polystyrene was investigated. Under the applied reaction conditions the main reaction product was 2,6,2',6'-tetramethyl-1,1'-dioxo-4,4'-bicyclohexa-2,5-dienylidene. It was found that the polymeric

  9. Theoretical studies of the functional role of the cross-linked histidine-tyrosine copper-B ligand of cytochrome c oxidase

    Science.gov (United States)

    McDonald, William J.

    In the present work density functional theory calculations were performed to explore the vibrational and electronic spectral changes associated with proton and electron transfer from the CuB center at the active site of cytochrome c oxidase that lead to the formation of either the PR or PM intermediates in the catalytic reduction of dioxygen to water. Furthermore, the thermodynamics of proton and electron transfer from the cross-linked histidine-tyrosine Cu B ligand were explored to assess the possible role of this ligand as a proton and/or electron donor during enzymatic turnover. Characteristic calculated cross-linked imidazole-phenolate and imidazole-phenoxyl radical vibrational frequencies and isotope shifts are in good agreement with the vibrational spectra of the PR and PM intermediates of the bo3 quinol oxidase from E. coli and R. sphaeroides and P. denitrificans suggesting that the Y244 (bovine numbering) is deprotonated in the PR intermediate, and is a tyrosyl radical in P M. Furthermore, using isodesmic reactions, the cross-linked phenol is found to be a significantly stronger acid than an unmodified phenol in the gas-phase, and likely in the inhomogeneous low-dielectric environment of the membrane bound enzyme, supporting the conclusion that the cross-linked tyrosine is a proton donor during enzymatic turnover. Time-dependent density functional theory calculations qualitatively reproduce the red-shift in the UV/visible absorption spectrum of a cross-linked imidazole-phenolate anion compared to the imidazole-phenol. Furthermore, the unique ˜500 nm absorption of a cross-linked imidazole-phenoxyl radical is correctly predicted using TDDFT and may be assigned as an imidazole-phenoxyl radical pi-to-pi* transition. Furthermore, this absorption is predicted in the spectrum of a Cu2+-imidazole-phenoxyl biradical model.

  10. Crystal Structure and Electrochemical Behavior of Copper Complex with 6-Hydroxymethyl-substituted Tris(2-pyridylmethyl) Amine,[CuCl(C19H20N4O)]ClO4

    Institute of Scientific and Technical Information of China (English)

    高云玲; 彭孝军; 孙世国; 孙立成; 陈昌能; 刘秋田; 黄德光

    2004-01-01

    A Cu(II) complex [CuCl(C19H20N4O)]ClO4 1 containing hydroxymethyl substituted TPA (TPA = tris(2-pyridylmethyl)amine) was prepared. It crystallizes in monoclinic, space group P21/c with a = 11.7628(2), b = 13.0083(3), c = 15.11280(10)A, β = 108.724(2)°, V = 2190.09(7)A3, Mr = 518.83, Z = 4, T = 293(2) K, Dc = 1.574 g/cm3, μ = 1.280 mm-1, F(000) = 1060 and S = 1.085. The final R = 0.0543 and wR = 0.1433 for 2693 observed reflections with I >2σ(I). The pentacoordinated copper (II) complex assumes an approximate square pyramidal geometry. Cyclic voltammetry measurement of the complex showed a quasi-reversible CuII/CuI redox couple with E1/2 = -0.467 v and ΔE = 68 mv.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-15

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

  12. EFFECT OF CROSSLINKING ON MITOCHONDRIAL CYTOCHROME c OXIDASE

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, Maurice; Packer, Lester

    1979-12-01

    Purified and reconstituted cytochrome {und c} oxidase and mitochondria were crosslinked with biimidates in the presence and absence of cytochrome {und c}. These experiments indicate that oxidase subunit interactions are required for activity and that cytochrome {und c} mobility may be required for electron transport activity. Biimidate treatment of purified and reconstituted oxidase crosslinks all of the oxidase protomers except subunit I when {ge} 20% of the free amines are modified and inhibits steady state oxidase activity. Transient kinetics of ferrocytochrome {und c} oxidation and ferricytochrome {und a} reduction indicates inhibition of electron transfer from heme {und a} to heme {und a}{sub 3}. Crosslinking oxidase molecules to form large aggregates displaying rotational correlation times {ge} 1 ms does not affect oxidase activity. Crosslinking of mitochondria covalently binds the bc{sub 1} and {und aa}{sub 3} complexes to cytochrome {und c}, and inhibits steady-state oxidase activity considerably more than in the case of the purified oxidase. Addition of cytochrome {und c} to the purified oxidase or to {und c}-depleted mitoplasts increases inhibition slightly. Cytochrome {und c} oligomers act as competitive inhibitors of native {und c}, however, crosslinking of cytochrome {und c} to {und c}-depleted mitoplasts or purified oxidase (with dimethyl suberimidate or hetrobifunctional crosslinking reagents) results in a catalytically inactive complex.

  13. Synthesis, characterization and catechol oxidase biomimetic catalytic activity of cobalt(II and copper(II complexes containing N2O2 donor sets of imine ligands

    Directory of Open Access Journals (Sweden)

    Mohamed I. Ayad

    2016-11-01

    Full Text Available New tetradentate imine ligands are derived from Schiff base condensation in a 1:2 molar ratio of the 1,2,4,5-tetra-amino benzene with 2-hydroxy benzaldehyde, (L1, 2,4-dihydroxy benzaldehyde (L2 and 2-hydroxy naphthaldehyde (L3. These ligands react with CoCl2 and CuCl2 in refluxing ethanol to yield a series of cobalt(II and copper(II complexes of the type [M2IILn] nH2O. The structure of the obtained ligands and their metal(II complexes were characterized by various physicochemical techniques, viz. elemental analysis, molar conductance, magnetic susceptibility measurements, thermal analysis (TGA & DTG, IR, electronic absorption and ESR spectral studies. Four-coordinate tetrahedral and square–planar structures were proposed for cobalt(II and copper(II complex species respectively. The ability of the synthesized complexes to catalyze the aerobic oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC to the light absorbing 3,5-di-tert-butylquinone (3,5-DTBQ has been investigated. The results obtained show that all complexes catalyze this oxidation reaction and slight variations in the rate were observed. The probable mechanistic implications of the catalytic oxidation reactions are discussed.

  14. Fixation Property of Copper Triazole Wood Preservatives

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    According to AWPA E11-2006 standard,copper fixation rates of several copper-based formulations,such as ammoniacal copper,amine copper,and ammoniacal-ethanolamine copper,as well as alkaline copper quaternary(ACQ),were tested and compared in this paper.And the fixation rates of tebuconazole(TEB) and propiconazole(PPZ) in several formulations,such as copper azole,emulsified type and solvent type,were also compared.The determination of copper content in the leachate was analyzed by atomic absorption spectrom...

  15. Intramolecular electron transfer in ascorbate oxidase is enhanced in the presence of oxygen

    DEFF Research Database (Denmark)

    Farver, O; Wherland, S; Pecht, I

    1994-01-01

    Intramolecular electron transfer from the type 1 copper center to the type 3 copper(II) pair is induced in the multi-copper enzyme, ascorbate oxidase, following pulse radiolytic reduction of the type 1 Cu(II) ion. In the presence of a slight excess of dioxygen over ascorbate oxidase, interaction...... between the trinuclear copper center and O2 is observed even with singly reduced ascorbate oxidase molecules. Under these conditions, the rate constant for intramolecular electron transfer from type 1 Cu(I) to type 3 Cu(II) increases 5-fold to 1100 +/- 300 s-1 (20 degrees C, pH 5.8) as compared...

  16. ADP competes with FAD binding in putrescine oxidase

    NARCIS (Netherlands)

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

    2008-01-01

    Putrescine oxidase from Rhodococcus erythropolis NCIMB 11540 (PuORh) is a soluble homodimeric flavoprotein of 100 kDa, which catalyzes the oxidative deamination of putrescine and some other aliphatic amines. The initial characterization of PuORh uncovered an intriguing feature: the enzyme appeared t

  17. Mixed ligand copper(II) complexes of N,N-bis(benzimidazol-2-ylmethyl)amine (BBA) with diimine co-ligands: efficient chemical nuclease and protease activities and cytotoxicity.

    Science.gov (United States)

    Loganathan, Rangasamy; Ramakrishnan, Sethu; Suresh, Eringathodi; Riyasdeen, Anvarbatcha; Akbarsha, Mohamad Abdulkadhar; Palaniandavar, Mallayan

    2012-05-21

    A series of mononuclear mixed ligand copper(II) complexes [Cu(bba)(diimine)](ClO(4))(2)1-4, where bba is N,N-bis(benzimidazol-2-ylmethyl)amine and diimine is 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), 5,6-dimethyl-1,10-phenanthroline (5,6-dmp) (3), or dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) (4), have been isolated and characterized by analytical and spectral methods. The coordination geometry around copper(II) in 2 is described as square pyramidal with the two benzimidazole nitrogen atoms of the primary ligand bba and the two nitrogen atoms of phen (2) co-ligand constituting the equatorial plane and the amine nitrogen atom of bba occupying the apical position. In contrast, the two benzimidazole nitrogen atoms and the amine nitrogen atom of bba ligand and one of the two nitrogen atoms of 5,6-dmp constitute the equatorial plane of the trigonal bipyramidal distorted square based pyramidal (TBDSBP) coordination geometry of 3 with the other nitrogen atom of 5,6-dmp occupying the apical position. The structures of 1-4 have been optimized by using the density functional theory (DFT) method at the B3LYP/6-31G(d,p) level. Absorption spectral titrations with Calf Thymus (CT) DNA reveal that the intrinsic DNA binding affinity of the complexes depends upon the diimine co-ligand, dpq (4) > 5,6-dmp (3) > phen (2) > bpy (1). The DNA binding affinity of 4 is higher than 2 revealing that the π-stacking interaction of the dpq ring in between the DNA base pairs with the two bzim moieties of the bba ligand stacked along the DNA surface is more intimate than that of phen. The complex 3 is bound to DNA more strongly than 1 and 2 through strong hydrophobic interaction of the methyl groups on 5,6-positions of the phen ring in the DNA grooves. The extent of the decrease in relative emission intensities of DNA-bound ethidium bromide (EB) upon adding the complexes parallels the trend in DNA binding affinities. The large enhancement in relative viscosity of DNA upon binding

  18. Structural and Functional Models for the Dinuclear Copper Active Site in Catechol Oxidases: Syntheses, X-ray Crystal Structures, Magnetic and Spectral Properties, and X-ray Absorption Spectroscopic Studies in Solid State and in Solution.

    Science.gov (United States)

    Zippel, Frank; Ahlers, Friedhelm; Werner, Rüdiger; Haase, Wolfgang; Nolting, Hans-Friedrich; Krebs, Bernt

    1996-05-22

    Two novel tridentate dinucleating ligands containing benzimidazole were prepared, 1,3-bis(2-benzimidazolyl)-2-propanol (Hbbp, 1) and 1,5-bis(2-benzimidazolyl)-3-pentanol (Hbbpen, 2). Their complexing properties toward copper were studied in order to obtain structural and functional models for catechol oxidases. Syntheses and crystal structures of dinuclear Cu(II) complexes derived from these ligands are reported. [Cu(2)bbp(2)](ClO(4))(2).2MeOH, 3, crystallizes in the triclinic space group P&onemacr; with the following unit cell parameters: a = 7.702(3) Å, b = 10.973(6) Å, c = 12.396(6) Å, alpha = 100.59(4) degrees, beta = 99.02(4) degrees, gamma = 98.90(4) degrees, V = 998.7(8) Å(3), and Z = 1. [Cu(2)bbpen(2)](ClO(4))(2).3MeOH, 4, crystallizes in the orthorhombic space group Pccn, with the following unit cell parameters: a = 17.478(9) Å, b = 18.795(8) Å, c = 13.888(6) Å, V = 4562.2(4) Å(3), and Z = 4. Magnetic susceptibility measurements in the temperature ranges 4.6-459 K (3) and 4.6-425 K (4) indicate an antiferromagnetic coupling between the Cu(II) centers of both complexes. In order to determine the structures of the complexes in solution, XAS spectra (EXAFS and XANES) were recorded in the solid state and in solution. The interpretation of these data, including multiple scattering calculations, together with UV-vis titrations, shows that the complexes have the same structure in the crystalline state as well as in methanolic solution. Complex 4 is able to oxidize 3,5-di-tert-butylcatechol (3,5-DTBC) to the quinone (catecholase activity). This reaction was also studied by XAS and UV-vis spectroscopy. These measurements reveal the reduction of Cu(II) to Cu(I) accompanied by a decrease of the coordination number.

  19. A metalloenzyme-like catalytic system for the chemoselective oxidative cross-coupling of primary amines to imines under ambient conditions.

    Science.gov (United States)

    Largeron, Martine; Fleury, Maurice-Bernard

    2015-02-23

    The direct oxidative cross-coupling of primary amines is a challenging transformation as homocoupling is usually preferred. We report herein the chemoselective preparation of cross-coupled imines through the synergistic combination of low loadings of Cu(II) metal-catalyst and o-iminoquinone organocatalyst under ambient conditions. This homogeneous cooperative catalytic system has been inspired by the reaction of copper amine oxidases, a family of metalloenzymes with quinone organic cofactors that mediate the selective oxidation of primary amines to aldehydes. After optimization, the desired cross-coupled imines are obtained in high yields with broad substrate scope through a transamination process that leads to the homocoupled imine intermediate, followed by dynamic transimination. The ability to carry out the reactions at room temperature and with ambient air, rather than molecular oxygen as the oxidant, and equimolar amounts of each coupling partner is particularly attractive from an environmentally viewpoint. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Catechol oxidase activity of a series of new dinuclear copper(II) complexes with 3,5-DTBC and TCC as substrates: syntheses, X-ray crystal structures, spectroscopic characterization of the adducts and kinetic studies.

    Science.gov (United States)

    Banu, Kazi Sabnam; Chattopadhyay, Tanmay; Banerjee, Arpita; Bhattacharya, Santanu; Suresh, Eringathodi; Nethaji, Munirathinam; Zangrando, Ennio; Das, Debasis

    2008-08-18

    A series of dinuclear copper(II) complexes has been synthesized with the aim to investigate their applicability as potential structure and function models for the active site of catechol oxidase enzyme. They have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis: [Cu 2(H 2L2 (2))(OH)(H 2O)(NO 3)](NO 3) 3.2H 2O ( 1), [Cu(HL1 (4))(H 2O)(NO 3)] 2(NO 3) 2.2H 2O ( 2), [Cu(L1 (1))(H 2O)(NO 3)] 2 ( 3), [Cu 2(L2 (3))(OH)(H 2O) 2](NO 3) 2, ( 4) and [Cu 2(L2 (1))(N 3) 3] ( 5) [L1 = 2-formyl-4-methyl-6R-iminomethyl-phenolato and L2 = 2,6-bis(R-iminomethyl)-4-methyl-phenolato; for L1 (1) and L2 (1), R = N-propylmorpholine; for L2 (2), R = N-ethylpiperazine; for L2 (3), R = N-ethylpyrrolidine, and for L1 (4), R = N-ethylmorpholine]. Dinuclear 1 and 4 possess two "end-off" compartmental ligands with exogenous mu-hydroxido and endogenous mu-phenoxido groups leading to intermetallic distances of 2.9794(15) and 2.9435(9) A, respectively; 2 and 3 are formed by two tridentate compartmental ligands where the copper centers are connected by endogenous phenoxido bridges with Cu-Cu separations of 3.0213(13) and 3.0152(15) A, respectively; 5 is built by an end-off compartmental ligand having exogenous mu-azido and endogenous mu-phenoxido groups with a Cu-Cu distance of 3.133(2) A (mean of two independent molecules). The catecholase activity of all of the complexes has been investigated in acetonitrile and methanol medium by UV-vis spectrophotometric study using 3,5-di- tert-butylcatechol (3,5-DTBC) and tetrachlorocatechol (TCC) as substrates. In acetonitrile medium, the conversion of 3,5-DTBC to 3,5-di- tert-butylbenzoquinone (3,5-DTBQ) catalyzed by 1- 5 is observed to proceed via the formation of two enzyme-substrate adducts, ES1 and ES2, detected spectroscopically for the first time. In methanol medium no such enzyme-substrate adduct has been detected, and the 3,5-DTBC to 3,5-DTBQ conversion is observed to be catalyzed by 1- 5

  1. Estradiol plays a role in regulating the expression of lysyl oxidase family genes in mouse urogenital tissues and human Ishikawa cells.

    Science.gov (United States)

    Zong, Wen; Jiang, Yan; Zhao, Jing; Zhang, Jian; Gao, Jian-gang

    2015-10-01

    The lysyl oxidase (LOX) family encodes the copper-dependent amine oxidases that play a key role in determining the tensile strength and structural integrity of connective tissues by catalyzing the crosslinking of elastin or collagen. Estrogen may upregulate the expression of LOX and lysyl oxidase-like 1 (LOXL1) in the vagina. The objective of this study was to determine the effect of estrogen on the expression of all LOX family genes in the urogenital tissues of accelerated ovarian aging mice and human Ishikawa cells. Mice and Ishikawa cells treated with estradiol (E2) showed increased expression of LOX family genes and transforming growth factor β1 (TGF-β1). Ishikawa cells treated with TGF-β1 also showed increased expression of LOX family genes. The Ishikawa cells were then treated with either E2 plus the TGF-β receptor (TGFBR) inhibitor SB431542 or E2 alone. The expression of LOX family genes induced by E2 was reduced in the Ishikawa cells treated with TGFBR inhibitor. Our results showed that E2 increased the expression of the LOX family genes, and suggest that this induction may be mediated by the TGF-β signal pathway. E2 may play a role in regulating the expression of LOX family genes.

  2. Semicarbazide sensitive amine oxidase activity in pathogenesis of type Ⅱcollagen-induced rheumatoid arthritis%Ⅱ型胶原诱导的类风湿性关节炎发病过程中氨基脲敏感性胺氧化酶的活性变化

    Institute of Scientific and Technical Information of China (English)

    李兴暖; 罗红军; 林哲绚; 李慧; 刘艳英

    2011-01-01

    Objective To investigate the change of semicarbazide sensitive amine oxidase ( SSAO ) activity in pathogenesis of type Ⅱ collagen -induced rheumatoid arthritis. Methods Caudal intradermal injection of type Ⅱ collagen were applied for construction of rheumatoid arthritis model in 25 Wistar rats, while another 5 Wistar rats were included for control. At baseline and on day 3 , 7, 14 and 21 , each 5 model rats were scarified for collection of plasma and ankles tissue. The SSAO enzyme activity, TNF - α and ICAM - 1 levels were measured. Results Rheumatoid arthritis occurred in model rats on day 12. In ankle tissues, SSAO enzyme activity began to increase on day 3, peaked on day 7, and declined afterward. However, no significant changes in plasma SSAO enzyme activity or TNF - α and ICAM - 1 levels in ankle tissues or plasma were found. Conclusion Changes in SSAO activity is assoicated with the pathogenesis of type Ⅱ collagen induced - rheumatoid arthritis.%目的 探讨氨基脲敏感性胺氧化酶(SSAO)活性在类风湿性关节炎发病过程中的变化.方法 取25只Wistar大鼠,尾根部多点注射Ⅱ型胶原制作类风湿性关节炎大鼠模型,以造模当天为0 d,在造模第3、7、14和21天,分别处死5只大鼠,取血浆和踝关节组织,分别检测SSAO活性、肿瘤坏死因子-α(TNF-α)和细胞间黏附分子-1(ICAM-1)水平.另取5只大鼠作为空白对照组.结果 造模后第12天大鼠开始发病;关节组织SSAO活性于造模第3天开始升高,第7天升高到最高,之后开始降低;血浆SSAO活性变化不明显.血浆和组织中TNF-α及ICAM-1水平均随关节炎发病过程出现显著变化.结论 Ⅱ型胶原大鼠关节炎发病过程中伴随有SSAO活性的变化.

  3. Differential Expression of the Three Multicopper Oxidases from Myxococcus xanthus▿

    Science.gov (United States)

    Sánchez-Sutil, María Celestina; Gómez-Santos, Nuria; Moraleda-Muñoz, Aurelio; Martins, Lígia O.; Pérez, Juana; Muñoz-Dorado, José

    2007-01-01

    Myxococcus xanthus is a soil bacterium that undergoes a unique life cycle among the prokaryotes upon starvation, which includes the formation of macroscopic structures, the fruiting bodies, and the differentiation of vegetative rods into coccoid myxospores. This peculiarity offers the opportunity to study the copper response in this bacterium in two different stages. In fact, M. xanthus vegetative rods exhibit 15-fold-greater resistance against copper than developing cells. However, cells preadapted to this metal reach the same levels of resistance during both stages. Analysis of the M. xanthus genome reveals that many of the genes involved in copper resistance are redundant, three of which encode proteins of the multicopper oxidase family (MCO). Each MCO gene exhibits a different expression profile in response to external copper addition. Promoters of cuoA and cuoB respond to Cu(II) ions during growth and development; however, they show a 10-fold-increased copper sensitivity during development. The promoter of cuoC shows copper-independent induction upon starvation, but it is copper up-regulated during growth. Phenotypic analyses of deletion mutants reveal that CuoB is involved in the primary copper-adaptive response; CuoA and CuoC are necessary for the maintenance of copper tolerance; and CuoC is required for normal development. These roles seem to be carried out through cuprous oxidase activity. PMID:17483223

  4. Structure-function characterization reveals new catalytic diversity in the galactose oxidase and glyoxal oxidase family.

    Science.gov (United States)

    Yin, DeLu Tyler; Urresti, Saioa; Lafond, Mickael; Johnston, Esther M; Derikvand, Fatemeh; Ciano, Luisa; Berrin, Jean-Guy; Henrissat, Bernard; Walton, Paul H; Davies, Gideon J; Brumer, Harry

    2015-12-18

    Alcohol oxidases, including carbohydrate oxidases, have a long history of research that has generated fundamental biological understanding and biotechnological applications. Despite a long history of study, the galactose 6-oxidase/glyoxal oxidase family of mononuclear copper-radical oxidases, Auxiliary Activity Family 5 (AA5), is currently represented by only very few characterized members. Here we report the recombinant production and detailed structure-function analyses of two homologues from the phytopathogenic fungi Colletotrichum graminicola and C. gloeosporioides, CgrAlcOx and CglAlcOx, respectively, to explore the wider biocatalytic potential in AA5. EPR spectroscopy and crystallographic analysis confirm a common active-site structure vis-à-vis the archetypal galactose 6-oxidase from Fusarium graminearum. Strikingly, however, CgrAlcOx and CglAlcOx are essentially incapable of oxidizing galactose and galactosides, but instead efficiently catalyse the oxidation of diverse aliphatic alcohols. The results highlight the significant potential of prospecting the evolutionary diversity of AA5 to reveal novel enzyme specificities, thereby informing both biology and applications.

  5. Structural insights into electron transfer in caa 3-type cytochrome oxidase

    OpenAIRE

    Lyons, Joseph A.; Aragão, David; Slattery, Orla; Pisliakov, Andrei V.; Soulimane, Tewfik; Caffrey, Martin

    2012-01-01

    Summary Paragraph Cytochrome c oxidase is a member of the heme copper oxidase superfamily (HCO) 1 . HCOs function as the terminal enzymes in the respiratory chain of mitochondria and aerobic prokaryotes, coupling molecular oxygen reduction to transmembrane proton pumping. Integral to the enzyme’s function is the transfer of electrons from cytochrome c to the oxidase via a transient association of the two proteins. Electron entry and exit are proposed to occur from the same site on cytochrome ...

  6. Mechanistic insights into C-H amination via dicopper nitrenes.

    Science.gov (United States)

    Aguila, Mae Joanne B; Badiei, Yosra M; Warren, Timothy H

    2013-06-26

    We examine important reactivity pathways relevant to stoichiometric and catalytic C-H amination via isolable β-diketiminato dicopper alkylnitrene intermediates {[Cl2NN]Cu}2(μ-NR). Kinetic studies involving the stoichiometric amination of ethylbenzene by {[Cl2NN]Cu}2(μ-N(t)Bu) (3) demonstrate that the terminal nitrene [Cl2NN]Cu═N(t)Bu is the active intermediate in C-H amination. Initial rates exhibit saturation behavior at high ethylbenzene loadings and an inverse dependence on the copper species [Cl2NN]Cu, both consistent with dissociation of a [Cl2NN]Cu fragment from 3 prior to C-H amination. C-H amination experiments employing 1,4-dimethylcyclohexane and benzylic radical clock substrate support a stepwise H-atom abstraction/radical rebound pathway. Dicopper nitrenes [Cu]2(μ-NCHRR') derived from 1° and 2° alkylazides are unstable toward tautomerization to copper(I) imine complexes [Cu](HN═CRR'), rendering 1° and 2° alkylnitrene complexes unsuitable for C-H amination.

  7. An Internal Reaction Chamber in Dimethylglycine Oxidase Provides Efficient Protection from Exposure to Toxic Formaldehyde*

    OpenAIRE

    Tralau, Tewes; Lafite, Pierre; Levy, Colin; Combe, John P.; Scrutton, Nigel S.; Leys, David

    2009-01-01

    We report a synthetic biology approach to demonstrate substrate channeling in an unusual bifunctional flavoprotein dimethylglycine oxidase. The catabolism of dimethylglycine through methyl group oxidation can potentially liberate toxic formaldehyde, a problem common to many amine oxidases and dehydrogenases. Using a novel synthetic in vivo reporter system for cellular formaldehyde, we found that the oxidation of dimethylglycine is coupled to the synthesis of 5,10-methylenetetrahydrofolate thr...

  8. Amine Functionalized Porous Network

    KAUST Repository

    Eddaoudi, Mohamed

    2015-05-28

    Amine groups can be introduced in porous materials by a direct (one pot) or post-synthetic modification (PSM) process on aldehyde groups, and the resulting porous materials have increased gas affinity.

  9. Síntese e caracterização de novos compostos de coordenação de cobre (II com ligantes não-simétricos N,O-doadores: contribuições para o sítio ativo da galactose oxidase Synthesis and characterization of new copper (II coordination compounds with unsymmetrical N,O-donor ligands: contributions for the galactose oxidase active site

    Directory of Open Access Journals (Sweden)

    Stela Maris de Moraes Romanowski

    2001-10-01

    Full Text Available The reactions of four new unsymmetrical N,O-donor ligands, {H2BBPETEN= [N-(2-hydroxybenzyl - N,N' - bis(2 methylpyridyl -N'-(hydroxyethyl ethylenodiamine], H3BPETEN=[N,N'- bis(2-hydroxybenzyl -N- (2-methylpyridyl -N'- (hydroxyethyl ethylenodiamine], HTPETEN=[N,N,N'- tris(2-methylpyridyl -N'- (hydroxyethyl ethylenodiamine] and H3BIMETEN=[N,N'-(2-hydroxybenzyl-N-(1-methylimidazol-2-il-methyl-N'- (hydroxyethylethylenodiamine]}, with Cu(II salts afforded the following mononuclear compounds: [CuII(HBBPETEN]ClO4, [CuII(H2BPETEN]ClO4 , [CuII(HTPETEN](PF62 and [CuII(H2BIMETEN]ClO4 . All were characterized by EPR, electronic spectroscopy and electrochemistry. The four copper (II compounds showed interesting electrochemistry properties. All presented an anodic wave that can be attributed to the Cu (I oxide formation at the electrode surface, or to a Cu0 sediment at the same surface or yet, to Cu(I -> Cu(II oxidation process with coupled chemistry reaction, due to their irreversibility. Two of the complexes are described as interesting synthetic models for the active site of the metalloenzyme galactose oxidase.

  10. Biogenic amines in beer

    OpenAIRE

    Čiháková, Dagmar

    2016-01-01

    This thesis deals with the technological process of brewing beer, describes the raw materials needed for its production, and points out the useful and harmful substances contained in beer as biogenic amines (BA). Furthermore, there are described the issues of biogenic amines in food and primarily in beer, which is a histamine, putrescine, cadaverine, tyramine and tryptamine. In the practical section BA was determined in lager bottom-fermented beers from local microbreweries and large industri...

  11. Copper-Catalyzed Three- Five- or Seven-Component Coupling Reactions: The Selective Synthesis of Cyanomethylamines, N,N-Bis(CyanomethylAmines and N,N'-Bis(CyanomethylMethylenediamines Based on a Strecker-Type Synthesis

    Directory of Open Access Journals (Sweden)

    Takeo Konakahara

    2013-10-01

    Full Text Available We have demonstrated that a cooperative catalytic system comprised of CuCl and Cu(OTf2 could be used to effectively catalyse the three-, five- and seven-component coupling reactions of aliphatic or aromatic amines, formaldehyde, and trimethylsilyl cyanide (TMSCN, and selectively produce in good yields the corresponding cyanomethylamines, N,N-bis(cyanomethylamines and N,N'-bis(cyanomethylmethylenediamines.

  12. Characterization of polyphenol oxidase from plants

    Institute of Scientific and Technical Information of China (English)

    LEI Dongfeng; FENG Yi; JIANG Dazong

    2004-01-01

    Polyphenol oxidase (PPO) which can mediate browning reaction is a bifunctional copper-containing enzyme encoded by plant nucleolus gene. It usually leads to excessive browning reaction which reduces the coercial profits of fruits and vegetables. In this paper, PPO genes and enzymes in plants are characterized systematically, and the latest progress is reviewed. Some clonings of PPOs genes are reported; the specific temporal and spatial expression pattern of PPOs genes is described; the model of the structure of the precursor form of catechol oxidase is introduced; the possible functions of PPOs in defending against pathogen, wounding, surrounding stress and other inducing factors are demonstrated; the induction and activation of latent PPOs in some plants is elucidated; the scheme of browning inhibition by L-cysteine is clarified; the mechanism of suicide inhibition of latent PPO and kinetic synergism are established. Furthermore, the area for future study is also discussed.

  13. High capacity immobilized amine sorbents

    Science.gov (United States)

    Gray, McMahan L.; Champagne, Kenneth J.; Soong, Yee; Filburn, Thomas

    2007-10-30

    A method is provided for making low-cost CO.sub.2 sorbents that can be used in large-scale gas-solid processes. The improved method entails treating an amine to increase the number of secondary amine groups and impregnating the amine in a porous solid support. The method increases the CO.sub.2 capture capacity and decreases the cost of utilizing an amine-enriched solid sorbent in CO.sub.2 capture systems.

  14. ANNALS EXPRESS: Caeruloplasmin oxidase activity- measurement in serum by use of o- dianisidine dihydrochloride on a microplate reader.

    Science.gov (United States)

    Stepien, Karolina Maria; Guy, Mark

    2017-01-01

    Background The enzymatic method of caeruloplasmin measurement is based on copper-dependent oxidase activity. The advantage of the oxidase determination is that it has a much lower detection limit compared to immunoassay-based methods. It has found its application in both the diagnosis of Wilson's disease and also in the monitoring of patients' response to treatment.

  15. CHITOSE AMINE & BODY ACUPOINTS' COSMETOLOGY

    Institute of Scientific and Technical Information of China (English)

    TEO Gek Chun

    2002-01-01

    @@ Chitose Amine is a natural substance which the body cells will readily absorb and it helps strengthen the immune system and reduces the cholesterol. Currently. Chitose Amine has been used widely in cosmetics and detoxification foods. The mian therapeutic properties of Chitose Amine in cosmetics are as follow:

  16. 由新型铜胺络合物模板剂设计合成活性优异的Cu-SSZ-13分子筛%Design and Synthesis of a Catalytically Active Cu-SSZ-13 Zeolite from a Copper-Amine Complex Template

    Institute of Scientific and Technical Information of China (English)

    任利敏; 肖丰收; 张一波; 曾尚景; 朱龙凤; 孙琦; 张海燕; 杨承广; 孟祥举; 杨向光

    2012-01-01

    The modern synthesis of zeolites typically uses organic structure-directing agents. Therefore, the developing of new templates is part of zeolite research. The design and synthesis of Cu-SSZ-13 using a novel template of a low-cost copper amine complex (Cu2+ coordinated with tetraethylenepentamine) were reported, where the copper amine complex is both a template for synthesizing the SSZ-13 structure and a source of copper species in the zeolite. The calculated size of the complex (0.728 nm × 0.922 nm) matches well with the CHA cages (0.73 nm x 1.2 nm), which are the building units of the SSZ-13 zeolite. Various techniques were used to investigate the chemical and physical properties of the synthesized zeolite. The results showed that the sample has the SSZ-13 zeolite structure, high crystallinity, adjustable Si/Al ratios, and controllable copper loading. Catalytic tests using the selective catalytic reduction of Noχ with NH3 showed that the Cu-SSZ-13 was a superior catalyst, and it can be important for the abatement of environmentally harmful Noχ.%以低廉的铜胺络合物为新型模板剂,成功地合成了含铜的SSZ-13沸石分子筛(Cu-ZJM-1).在合成过程中,铜胺络合物既是模板分子,又是催化活性组分铜物种的直接来源.理论计算表明,该模板分子的构型与尺寸恰好与构成SSZ-13分子筛结构的CHA笼相匹配,因而可以成功地导向该沸石分子筛结构.采用X射线衍射、扫描电镜、氮气吸附、红外、紫外-可见吸收光谱、差热-热重分析、氨气程序升温脱附及氢气程序升温还原等手段对样品的性质及模板分子的状态进行了系统表征.结果表明,所制Cu-ZJM-1样品为结晶度很高的SSZ-13沸石结构,硅铝比和铜负载量可调且铜处于高分散状态,在NH3选择催化还原氮氧化物反应中表现出优异的催化性能.

  17. Proton transfer in ba(3) cytochrome c oxidase from Thermus thermophilus.

    Science.gov (United States)

    von Ballmoos, Christoph; Adelroth, Pia; Gennis, Robert B; Brzezinski, Peter

    2012-04-01

    The respiratory heme-copper oxidases catalyze reduction of O(2) to H(2)O, linking this process to transmembrane proton pumping. These oxidases have been classified according to the architecture, location and number of proton pathways. Most structural and functional studies to date have been performed on the A-class oxidases, which includes those that are found in the inner mitochondrial membrane and bacteria such as Rhodobacter sphaeroides and Paracoccus denitrificans (aa(3)-type oxidases in these bacteria). These oxidases pump protons with a stoichiometry of one proton per electron transferred to the catalytic site. The bacterial A-class oxidases use two proton pathways (denoted by letters D and K, respectively), for the transfer of protons to the catalytic site, and protons that are pumped across the membrane. The B-type oxidases such as, for example, the ba(3) oxidase from Thermus thermophilus, pump protons with a lower stoichiometry of 0.5 H(+)/electron and use only one proton pathway for the transfer of all protons. This pathway overlaps in space with the K pathway in the A class oxidases without showing any sequence homology though. Here, we review the functional properties of the A- and the B-class ba(3) oxidases with a focus on mechanisms of proton transfer and pumping. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Hydrothermal Reactivity of Amines

    Science.gov (United States)

    Robinson, K.; Shock, E.; Hartnett, H. E.; Williams, L. B.; Gould, I.

    2013-12-01

    The reactivity of aqueous amines depends on temperature, pH, and redox state [1], all of which are highly variable in hydrothermal systems. Temperature and pH affect the ratio of protonated to unprotonated amines (R-NH2 + H+ = R-NH3+), which act as nucleophiles and electrophiles, respectively. We hypothesize that this dual nature can explain the pH dependence of reaction rates, and predict that rates will approach a maximum at pH = pKa where the ratio of protonated and unprotonated amines approaches one and the two compounds are poised to react with one another. Higher temperatures in hydrothermal systems allow for more rapid reaction rates, readily reversible reactions, and unique carbon-nitrogen chemistry in which water acts as a reagent in addition to being the solvent. In this study, aqueous benzylamine was used as a model compound to explore the reaction mechanisms, kinetics, and equilibria of amines under hydrothermal conditions. Experiments were carried out in anoxic silica glass tubes at 250°C (Psat) using phosphate-buffered solutions to observe changes in reaction rates and product distributions as a function of pH. The rate of decomposition of benzylamine was much faster at pH 4 than at pH 9, consistent with the prediction that benzylamine acts as both nucleophile and an electrophile, and our estimate that the pKa of benzylamine is ~5 at 250°C and Psat. Accordingly, dibenzylamine is the primary product of the reaction of two benzylamine molecules, and this reaction is readily reversible under hydrothermal conditions. Extremely acidic or basic pH can be used to suppress dibenzylamine production, which also suppresses the formation of all other major products, including toluene, benzyl alcohol, dibenzylimine, and tribenzylamine. This suggests that dibenzylamine is the lone primary product that then itself reacts as a precursor to produce the above compounds. Analog experiments performed with ring-substituted benzylamine derivatives and chiral

  19. CotA, a multicopper oxidase from Bacillus pumilus WH4, exhibits manganese-oxidase activity.

    Directory of Open Access Journals (Sweden)

    Jianmei Su

    Full Text Available Multicopper oxidases (MCOs are a family of enzymes that use copper ions as cofactors to oxidize various substrates. Previous research has demonstrated that several MCOs such as MnxG, MofA and MoxA can act as putative Mn(II oxidases. Meanwhile, the endospore coat protein CotA from Bacillus species has been confirmed as a typical MCO. To study the relationship between CotA and the Mn(II oxidation, the cotA gene from a highly active Mn(II-oxidizing strain Bacillus pumilus WH4 was cloned and overexpressed in Escherichia coli strain M15. The purified CotA contained approximately four copper atoms per molecule and showed spectroscopic properties typical of blue copper oxidases. Importantly, apart from the laccase activities, the CotA also displayed substantial Mn(II-oxidase activities both in liquid culture system and native polyacrylamide gel electrophoresis. The optimum Mn(II oxidase activity was obtained at 53°C in HEPES buffer (pH 8.0 supplemented with 0.8 mM CuCl2. Besides, the addition of o-phenanthroline and EDTA both led to a complete suppression of Mn(II-oxidizing activity. The specific activity of purified CotA towards Mn(II was 0.27 U/mg. The Km, Vmax and kcat values towards Mn(II were 14.85±1.17 mM, 3.01×10(-6±0.21 M·min(-1 and 0.32±0.02 s(-1, respectively. Moreover, the Mn(II-oxidizing activity of the recombinant E. coli strain M15-pQE-cotA was significantly increased when cultured both in Mn-containing K liquid medium and on agar plates. After 7-day liquid cultivation, M15-pQE-cotA resulted in 18.2% removal of Mn(II from the medium. Furthermore, the biogenic Mn oxides were clearly observed on the cell surfaces of M15-pQE-cotA by scanning electron microscopy. To our knowledge, this is the first report that provides the direct observation of Mn(II oxidation with the heterologously expressed protein CotA, Therefore, this novel finding not only establishes the foundation for in-depth study of Mn(II oxidation mechanisms, but also offers

  20. Copper deficiency in patients with cystinosis with cysteamine toxicity

    DEFF Research Database (Denmark)

    Besouw, Martine T P; Schneider, Jerry; Janssen, Mirian C;

    2013-01-01

    To assess whether copper deficiency plays a role in the recently described cysteamine toxicity in patients with cystinosis, and to examine whether polymorphisms in copper transporters, lysyl oxidase, and/or type I procollagen genes could be responsible for the occurrence of cysteamine toxicity in...

  1. Solid-phase extraction of copper(II) in water and food samples using silica gel modified with bis(3-aminopropyl)amine and determination by flame atomic absorption spectrometry.

    Science.gov (United States)

    Cagirdi, Duygu; Altundag, Hüseyin; Imamoglu, Mustafa; Tuzen, Mustafa

    2014-01-01

    A simple and selective separation and preconcentration method was developed for the determination of Cu(ll) ions. This method is based on adsorption of Cu(ll) ions from aqueous solution on a bis(3-aminopropyl)amine modified silica gel column and flame atomic absorption spectrometric determination after desorption. Various analytical parameters such as pH, type of eluent solution and its volume, flow rate of sample and eluent, and sample volume were optimized. Effects of some cation, anion, and transition metal ions on the recoveries of Cu(ll) ions were also investigated. Cu(ll) ions were quantitatively recovered at pH 6; 5.0 mL of 2 M HCI was used as the eluent. The preconcentration factor was found to be 150. The LOD was 0.12 microg/L for Cu(ll). The accuracy of the method was confirmed by analysis of Tea Leaves (INCT-TL-1) and Fish Protein (DORM-3) certified reference materials. The optimized method was applied to various water and food samples for the determination of Cu(ll).

  2. ORGANIC CHEMISTRY. Catalytic asymmetric hydroamination of unactivated internal olefins to aliphatic amines.

    Science.gov (United States)

    Yang, Yang; Shi, Shi-Liang; Niu, Dawen; Liu, Peng; Buchwald, Stephen L

    2015-07-01

    Catalytic assembly of enantiopure aliphatic amines from abundant and readily available precursors has long been recognized as a paramount challenge in synthetic chemistry. Here, we describe a mild and general copper-catalyzed hydroamination that effectively converts unactivated internal olefins—an important yet unexploited class of abundant feedstock chemicals—into highly enantioenriched α-branched amines (≥96% enantiomeric excess) featuring two minimally differentiated aliphatic substituents. This method provides a powerful means to access a broad range of advanced, highly functionalized enantioenriched amines of interest in pharmaceutical research and other areas.

  3. A predicted structure of the cytochrome c oxidase from Burkholderia pseudomallei

    OpenAIRE

    Mohd. Raih,Mohd. Firdaus; Sailan,Ahmad Tarmidi; Zamrod,Zulkeflie; Embi,Mohd. Noor; Mohamed, Rahmah

    2003-01-01

    Cytochrome c oxidase, the terminal enzyme of the respiratory chains of mitochondria and aerobic bacteria, catalyzes electron transfer from cytochrome c to molecular oxygen. The enzyme belongs to the haem-copper-containing oxidases superfamily. A recombinant plasmid carrying a 2.0 kb insert from a Burkholderia pseudomallei genomic library was subjected to automated DNA sequencing utilizing a primer walking strategy. Analysis of the 2002 bp insert revealed a 1536 bp open reading frame predicted...

  4. Synthesis of Two Potentially Heptadentate (N4O3 Schiff-base Ligands Derived from Condensation of Tris(3-aminopropyl-amine and Salicylaldehyde or 4-Hydroxysalicylaldehyde. Nickel(II and Copper(II Complexes of the Former Ligand

    Directory of Open Access Journals (Sweden)

    R. V. Parish

    2002-02-01

    Full Text Available Two potentially heptadentate (N4O3 tripodal Schiff-base ligands: tris(3-(salicylideneiminopropylamine (H3L1 and tris(3-(4’-hydroxysalicylideneimino-propylamine (H3L2 have been prepared and characterized by various spectroscopic methods (IR, FAB-MS, NMR. They are derived from the condensation reactions of tris(3-aminopropylamine (tpt, with 3 equivalents of either salicylaldehyde or the ringsubstituted salicylaldehyde, 4-hydroxysalicylaldehyde. The nickel(II and copper(II complexes of H3L1 were obtained from the its reactions Ni(II and Cu(II salts in absolute methanol. These complexes were studied by IR and FAB-Mass spectrometry.

  5. Biogenic Amine Degradation by Bacillus Species Isolated from Traditional Fermented Soybean Food and Detection of Decarboxylase-Related Genes.

    Science.gov (United States)

    Eom, Jeong Seon; Seo, Bo Young; Choi, Hye Sun

    2015-09-01

    Biogenic amines in some food products present considerable toxicological risks as potential human carcinogens when consumed in excess concentrations. In this study, we investigated the degradation of the biogenic amines histamine and tyramine and the presence of genes encoding histidine and tyrosine decarboxylases and amine oxidase in Bacillus species isolated from fermented soybean food. No expression of histidine and tyrosine decarboxylase genes (hdc and tydc) were detected in the Bacillus species isolated (B. subtilis HJ0-6, B. subtilis D'J53-4, and B. idriensis RD13-10), although substantial levels of amine oxidase gene (yobN) expression were observed. We also found that the three selected strains, as non-biogenic amineproducing bacteria, were significantly able to degrade the biogenic amines histamine and tyramine. These results indicated that the selected Bacillus species could be used as a starter culture for the control of biogenic amine accumulation and degradation in food. Our study findings also provided the basis for the development of potential biological control agents against these biogenic amines for use in the food preservation and food safety sectors.

  6. Isolated sulfite oxidase deficiency.

    Science.gov (United States)

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

    2015-03-10

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

  7. Bioavailable copper modulates oxidative phosphorylation and growth of tumors.

    Science.gov (United States)

    Ishida, Seiko; Andreux, Pénélope; Poitry-Yamate, Carole; Auwerx, Johan; Hanahan, Douglas

    2013-11-26

    Copper is an essential trace element, the imbalances of which are associated with various pathological conditions, including cancer, albeit via largely undefined molecular and cellular mechanisms. Here we provide evidence that levels of bioavailable copper modulate tumor growth. Chronic exposure to elevated levels of copper in drinking water, corresponding to the maximum allowed in public water supplies, stimulated proliferation of cancer cells and de novo pancreatic tumor growth in mice. Conversely, reducing systemic copper levels with a chelating drug, clinically used to treat copper disorders, impaired both. Under such copper limitation, tumors displayed decreased activity of the copper-binding mitochondrial enzyme cytochrome c oxidase and reduced ATP levels, despite enhanced glycolysis, which was not accompanied by increased invasiveness of tumors. The antiproliferative effect of copper chelation was enhanced when combined with inhibitors of glycolysis. Interestingly, larger tumors contained less copper than smaller tumors and exhibited comparatively lower activity of cytochrome c oxidase and increased glucose uptake. These results establish copper as a tumor promoter and reveal that varying levels of copper serves to regulate oxidative phosphorylation in rapidly proliferating cancer cells inside solid tumors. Thus, activation of glycolysis in tumors may in part reflect insufficient copper bioavailability in the tumor microenvironment.

  8. A Plasmodium falciparum copper-binding membrane protein with copper transport motifs

    Directory of Open Access Journals (Sweden)

    Choveaux David L

    2012-11-01

    Full Text Available Abstract Background Copper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper still remains to be fully elucidated. Methods PlasmoDB was searched for sequences corresponding to candidate P. falciparum copper-requiring proteins. The amino terminal domain of a putative P. falciparum copper transport protein was cloned and expressed as a maltose binding fusion protein. The copper binding ability of this protein was examined. Copper transport protein-specific anti-peptide antibodies were generated in chickens and used to establish native protein localization in P. falciparum parasites by immunofluorescence microscopy. Results Six P. falciparum copper-requiring protein orthologs and a candidate P. falciparum copper transport protein (PF14_0369, containing characteristic copper transport protein features, were identified in PlasmoDB. The recombinant amino terminal domain of the transport protein bound reduced copper in vitro and within Escherichia coli cells during recombinant expression. Immunolocalization studies tracked the copper binding protein translocating from the erythrocyte plasma membrane in early ring stage to a parasite membrane as the parasites developed to schizonts. The protein appears to be a PEXEL-negative membrane protein. Conclusion Plasmodium falciparum parasites express a native protein with copper transporter characteristics that binds copper in vitro. Localization of the protein to the erythrocyte and parasite plasma membranes could provide a mechanism for the delivery of novel anti-malarial compounds.

  9. Oxygen binding and activation by the complexes of PY2- and TPA-appended diphenylglycoluril receptors with copper and other metals

    NARCIS (Netherlands)

    Sprakel, VSI; Feiters, MC; Klaucke, WM; Klopstra, M; Brinksma, J; Feringa, BL; Karlin, KD; Nolte, RJM; Sprakel, Vera S.I.; Feiters, Martin C.; Meyer-Klaucke, Wolfram; Karlin, Kenneth D.; Nolte, Roeland J.M.; Feringa, Bernard

    2005-01-01

    The copper( I) complexes of diphenylglycoluril basket receptors 1 and 2, appended with bis(2-ethylpyridine) amine (PY2) and tris(2-methylpyridine) amine (TPA), respectively, and their dioxygen adducts were studied with low-temperature UV-vis and X-ray absorption spectroscopy (XAS). The copper(I) com

  10. Copper hypersensitivity.

    Science.gov (United States)

    Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P

    2014-10-01

    The world production of copper is steadily increasing. Although humans are widely exposed to copper-containing items on the skin and mucosa, allergic reactions to copper are only infrequently reported. To review the chemistry, biology and accessible data to clarify the implications of copper hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common. As a metal, it possesses many of the same qualities as nickel, which is a known strong sensitizer. Cumulative data on subjects with presumed related symptoms and/or suspected exposure showed that a weighted average of 3.8% had a positive patch test reaction to copper. We conclude that copper is a very weak sensitizer as compared with other metal compounds. However, in a few and selected cases, copper can result in clinically relevant allergic reactions.

  11. The Fox1 Ferroxidase of Chlamydomonas reinhardtii: A New Multicopper Oxidase Structural Paradigm

    OpenAIRE

    Terzulli, Alaina J.; Kosman, Daniel J

    2008-01-01

    Multicopper oxidases (MCO) contain at least four copper atoms arrayed in three distinct ligand fields supported by two canonical structural features: 1) multiples of the cupredoxin fold; and 2) four unique sequence elements that include the 10 histidine and one cysteine ligands to the four copper atoms. Ferroxidases are a sub-family of MCO proteins that contain residues supporting a specific reactivity towards ferrous iron; these MCOs play a vital role in iron metabolism in bacteria, algae, f...

  12. Comparative genomic analyses of copper transporters and cuproproteomes reveal evolutionary dynamics of copper utilization and its link to oxygen.

    Directory of Open Access Journals (Sweden)

    Perry G Ridge

    Full Text Available Copper is an essential trace element in many organisms and is utilized in all domains of life. It is often used as a cofactor of redox proteins, but is also a toxic metal ion. Intracellular copper must be carefully handled to prevent the formation of reactive oxygen species which pose a threat to DNA, lipids, and proteins. In this work, we examined patterns of copper utilization in prokaryotes by analyzing the occurrence of copper transporters and copper-containing proteins. Many organisms, including those that lack copper-dependent proteins, had copper exporters, likely to protect against copper ions that inadvertently enter the cell. We found that copper use is widespread among prokaryotes, but also identified several phyla that lack cuproproteins. This is in contrast to the use of other trace elements, such as selenium, which shows more scattered and reduced usage, yet larger selenoproteomes. Copper transporters had different patterns of occurrence than cuproproteins, suggesting that the pathways of copper utilization and copper detoxification are independent of each other. We present evidence that organisms living in oxygen-rich environments utilize copper, whereas the majority of anaerobic organisms do not. In addition, among copper users, cuproproteomes of aerobic organisms were larger than those of anaerobic organisms. Prokaryotic cuproproteomes were small and dominated by a single protein, cytochrome c oxidase. The data are consistent with the idea that proteins evolved to utilize copper following the oxygenation of the Earth.

  13. Copper catalyzed synthesis of quinolinopyrano[2,3-]carbazole derivatives via Povarov reaction

    Indian Academy of Sciences (India)

    Subburethinam Ramesh; Rajagopal Nagarajan

    2014-07-01

    An efficient procedure for the synthesis of pyranocarbazole derivatives using copper catalysed Povarov reaction between aromatic amines and -propargyl carbazole carboxaldehyde has been developed. Ionic liquid is found to be a good solvent medium.

  14. Copper transport.

    Science.gov (United States)

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N

    1998-05-01

    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

  15. Oxidation of amines by yeasts grown on 1-aminoalkanes or putrescine as the sole source of carbon, nitrogen and energy.

    Science.gov (United States)

    Middlehoven, W J; Hoogkamer-Te Niet, M C; De Laat, W T; Weijers, C; Bulder, C J

    1986-01-01

    The maximum growth rate of Trichosporon cutaneum CBS 8111 in chemostat cultures was 0.185 h-1 on ethylamine and 0.21 h-1 on butylamine, that of Candida famata CBS 8109 was 0.32 h-1 on putrescine. The amine oxidation pattern of the ascomycetous strains studied, viz. Candida famata CBS 8109, Stephanoascus ciferrii CBS 4856 and Trichosporon adeninovorans CBS 8244 was independent of the amine that had been used as the growth substrate. It resembled that of benzylamine/putrescine oxidase found in other ascomycetous yeasts. However, differences in pH optimum and substrate specificity were observed between the amine-oxidizing systems of these three species. The amine oxidation pattern of cell-free extracts of Trichosporon cutaneum CBS 8111 varied with the amine that was used as growth substrate. The enzyme system produced by Cryptococcus laurentii CBS 7140 failed to oxidize isobutylamine and benzylamine, and showed a high pH optimum. The synthesis of amine oxidase in the four yeast strains studied was not repressed by ammonium chloride and was weakly repressed by glucose but was strongly repressed if both compounds were present in the growth medium.

  16. Copper hypersensitivity

    DEFF Research Database (Denmark)

    Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P

    2014-01-01

    hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common...

  17. Vectorially oriented monolayers of the cytochrome c/cytochrome oxidase bimolecular complex.

    OpenAIRE

    Edwards, A M; Blasie, J. K.; Bean, J. C.

    1998-01-01

    Vectorially oriented monolayers of yeast cytochrome c and its bimolecular complex with bovine heart cytochrome c oxidase have been formed by self-assembly from solution. Both quartz and Ge/Si multilayer substrates were chemical vapor deposited with an amine-terminated alkylsiloxane monolayer that was then reacted with a hetero-bifunctional cross-linking reagent, and the resulting maleimide endgroup surface then provided for covalent interactions with the naturally occurring single surface cys...

  18. Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); van Hest, Marinus Franciscus Antonius Maria (Lakewood, CO); Ginley, David S. (Evergreen, CO); Leisch, Jennifer (Denver, CO); Taylor, Matthew (West Simsbury, CT); Stanbery, Billy J. (Austin, TX)

    2011-09-20

    Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

  19. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis.

    Science.gov (United States)

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

    2014-10-01

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

  20. Mitochondrial dysfunction in neurodegenerative diseases associated with copper imbalance.

    Science.gov (United States)

    Rossi, Luisa; Lombardo, Marco F; Ciriolo, Maria R; Rotilio, Giuseppe

    2004-03-01

    Copper is an essential transition metal ion for the function of key metabolic enzymes, but its uncontrolled redox reactivity is source of reactive oxygen species. Therefore a network of transporters strictly controls the trafficking of copper in living systems. Deficit, excess, or aberrant coordination of copper are conditions that may be detrimental, especially for neuronal cells, which are particularly sensitive to oxidative stress. Indeed, the genetic disturbances of copper homeostasis, Menkes' and Wilson's diseases, are associated with neurodegeneration. Furthermore, copper interacts with the proteins that are the hallmarks of neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, prion diseases, and familial amyotrophic lateral sclerosis. In all cases, copper-mediated oxidative stress is linked to mitochondrial dysfunction, which is a common feature of neurodegeneration. In particular we recently demonstrated that in copper deficiency, mitochondrial function is impaired due to decreased activity of cytochrome c oxidase, leading to production of reactive oxygen species, which in turn triggers mitochondria-mediated apoptotic neurodegeneration.

  1. Voltammetry and single-molecule in situ scanning tunneling microscopy of laccases and bilirubin oxidase in electrocatalytic dioxygen reduction on Au(111) single-crystal electrodes

    DEFF Research Database (Denmark)

    Climent, Victor; Zhang, Jingdong; Friis, Esben Peter;

    2012-01-01

    Laccases (E.C. 1.10.3.2) are multicopper oxidases catalytically active in the oxidation of diphenolics and related compounds by molecular dioxygen. The laccases contain a single-copper type I center and a trinuclear cluster of a single-copper type II and a dinuclear type III center. The oxidation...

  2. Amine-Amine Exchange in Aminium-Methanesulfonate Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Matthew L.; Varner, Mychel E.; Perraud, Veronique M.; Ezell, Michael J.; Wilson, Jacqueline M.; Zelenyuk, Alla; Gerber, Robert B.; Finlayson-Pitts, Barbara J.

    2014-12-18

    Aerosol particles are ubiquitous in the atmosphere and have been shown to impact the Earth’s climate, reduce visibility, and adversely affect human health. Modeling the evolution of aerosol systems requires an understanding of the species and mechanisms involved in particle growth, including the complex interactions between particle- and gas-phase species. Here we report studies of displacement of amines (methylamine, dimethylamine or trimethylamine) in methanesulfonate salt particles by exposure to a different gas-phase amine, using a single particle mass spectrometer, SPLAT II. The variation of the displacement with the nature of the amine suggests that behavior is dependent on water in or on the particles. Small clusters of methanesulfonic acid with amines are used as a model in quantum chemical calculations to identify key structural elements that are expected to influence water uptake, and hence the efficiency of displacement by gas-phase molecules in the aminium salts. Such molecular-level understanding of the processes affecting the ability of gas-phase amines to displace particle-phase aminium species is important for modeling the growth of particles and their impacts in the atmosphere.

  3. Lysyl oxidase in colorectal cancer.

    Science.gov (United States)

    Cox, Thomas R; Erler, Janine T

    2013-11-15

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

  4. Improved behavior of cooper-amine complexes during thermal annealing for conductive thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ayag, Kevin Ray; Panama, Gustavo; Paul, Shrabani; Kim, Hong Doo [Dept. of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin (Korea, Republic of)

    2017-02-15

    Previous studies successfully produced conductive thin films from organo-metallic-compounds-based inks. Some inks like those made from copper salt and amines, however, tend to move during thermal annealing and, thus, affect the conductive pattern on the substrate. In this study, conductive inks were synthesized by forming complexes of copper with amines and/or blended amines. To build-up an organo-metallic framework and preserve the pattern throughout the annealing period, diamine was added to the complex in different proportions. The prepared inks were coated on glass substrate and were annealed on a hot plate at 170°C under the gaseous mixture of formic acid and alcohol for 5 min. The metallic film was observed to retain the original pattern of the ink during and after annealing. Adhesion on the substrate was also improved. Inks with blended amines produced films with lower resistivities. The lowest electrical resistivity recorded was 4.99 μΩ cm, three times that of bulk copper.

  5. Amine Swingbed Payload Project Management

    Science.gov (United States)

    Walsch, Mary; Curley, Su

    2013-01-01

    The International Space Station (ISS) has been designed as a laboratory for demonstrating technologies in a microgravity environment, benefitting exploration programs by reducing the overall risk of implementing such technologies in new spacecraft. At the beginning of fiscal year 2010, the ISS program manager requested that the amine-based, pressure-swing carbon dioxide and humidity absorption technology (designed by Hamilton Sundstrand, baselined for the Orion Multi-Purpose Crew Vehicle, and tested at the Johnson Space Center in relevant environments, including with humans, since 2005) be developed into a payload for ISS Utilization. In addition to evaluating the amine technology in a flight environment before the first launch of the Orion vehicle, the ISS program wanted to determine the capability of the amine technology to remove carbon dioxide from the ISS cabin environment at the metabolic rate of the full 6 ]person crew. Because the amine technology vents the absorbed carbon dioxide and water vapor to space vacuum (open loop), additional hardware needed to be developed to minimize the amount of air and water resources lost overboard. Additionally, the payload system would be launched on two separate Space Shuttle flights, with the heart of the payload-the swingbed unit itself-launching a full year before the remainder of the payload. This paper discusses the project management and challenges of developing the amine swingbed payload in order to accomplish the technology objectives of both the open -loop Orion application as well as the closed-loop ISS application.

  6. Amine Swingbed Payload Technology Demonstration

    Science.gov (United States)

    Sweterlitsch, Jeffrey

    2014-01-01

    The Amine Swingbed is an amine-based, vacuum-regenerated adsorption technology for removing carbon dioxide and humidity from a habitable spacecraft environment, and is the baseline technology for the Orion Program’s Multi-Purpose Crew Vehicle (MPCV). It uses a pair of interleaved-layer beds filled with SA9T, the amine sorbent, and a linear multiball valve rotates 270° back and forth to control the flow of air and vacuum to adsorbing and desorbing beds. One bed adsorbs CO2 and H2O from cabin air while the other bed is exposed to vacuum for regeneration by venting the CO2 and H2O. The two beds are thermally linked, so no additional heating or cooling is required. The technology can be applied to habitable environments where recycling CO2 and H2O is not required such as short duration missions.

  7. Unprecedented copper(I) bifluoride complexes: synthesis, characterization and reactivity.

    Science.gov (United States)

    Vergote, Thomas; Nahra, Fady; Welle, Alexandre; Luhmer, Michel; Wouters, Johan; Mager, Nathalie; Riant, Olivier; Leyssens, Tom

    2012-01-16

    To be or not to bifluoride: Two synthetic pathways to unprecedented N-heterocyclic carbene copper(I) bifluoride complexes have been developed. Catalytic tests demonstrated that copper(I) bifluorides are very efficient catalysts, which do not require any additional activating agent. The first Cu-catalyzed diastereoselective allylation of (R)-N-tert-butanesulfinyl aldimines was also established. The method enables efficient, simple and general synthesis of enantiomerically enriched homoallylic amines at room temperature in high yields.

  8. Complex amine-based reagents

    Science.gov (United States)

    Suslov, S. Yu.; Kirilina, A. V.; Sergeev, I. A.; Zezyulya, T. V.; Sokolova, E. A.; Eremina, E. V.; Timofeev, N. V.

    2017-03-01

    Amines for a long time have been applied to maintaining water chemistry conditions (WCC) at power plants. However, making use of complex reagents that are the mixture of neutralizing and the filmforming amines, which may also contain other organic components, causes many disputes. This is mainly due to lack of reliable information about these components. The protective properties of any amine with regard to metal surfaces depend on several factors, which are considered in this article. The results of applying complex reagents to the protection of heating surfaces in industrial conditions and estimated behavior forecasts for various reagents under maintaining WCC on heat-recovery boilers with different thermal circuits are presented. The case of a two-drum heat-recovery boiler with in-line drums was used as an example, for which we present the calculated pH values for various brands of reagents under the same conditions. Work with different reagent brands and its analysis enabled us to derive a composition best suitable for the conditions of their practical applications in heat-recovery boilers at different pressures. Testing the new amine reagent performed at a CCPP power unit shows that this reagent is an adequate base for further development of reagents based on amine compounds. An example of testing a complex reagent is shown created with the participation of the authors within the framework the program of import substitution and its possible use is demonstrated for maintaining WCC of power-generating units of combined-cycle power plants (CCPP) and TPP. The compliance of the employed reagents with the standards of water chemistry conditions and protection of heating surfaces were assessed. The application of amine-containing reagents at power-generating units of TPP makes it possible to solve complex problems aimed at ensuring the sparing cleaning of heating surfaces from deposits and the implementation of conservation and management of water chemistry condition

  9. Blue copper proteins as a model for investigating electron transfer processes within polypeptide matrices

    DEFF Research Database (Denmark)

    Farver, O; Pecht, I

    1994-01-01

    : (1) Their sole physiological role is mediating or catalyzing ET processes via the evolutionary optimized copper sites. (2) The three-dimensional structures of a considerable number of blue single copper containing proteins, e.g. azurins, and of ascorbate oxidase, have been determined at high...

  10. A novel terminal oxidase, cytochrome baa3 purified from aerobically grown Pseudomonas aeruginosa: it shows a clear difference between resting state and pulsed state.

    Science.gov (United States)

    Fujiwara, T; Fukumori, Y; Yamanaka, T

    1992-08-01

    A novel type of cytochrome c oxidase was purified to homogeneity from Pseudomonas aeruginosa which was grown aerobically. The purified oxidase contained two molecules of heme a, two atoms of copper, and one molecule of protoheme per molecule. One of the two heme a molecules in the oxidase reacted with carbon monoxide, so that the enzyme was of baa3-type. The oxidase molecule was composed of three subunits with molecular weights of 38,000, 57,000, and 82,000. Although the oxidase oxidized ferrocytochrome c-550 obtained from the bacterial cells grown aerobically, the oxidizing activity was not high. The "resting form" and the "pulsed form" of the oxidase were observed clearly with this enzyme, and the transition from the resting form to the pulsed form was accompanied by a distinct change of the enzymatic activity. The difference in the kinetics of the catalytic reactions between the two forms is discussed.

  11. Bacterial degradation of monocyclic aromatic amines

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-08-01

    Full Text Available Aromatic amines are an important group of industrial chemicals, which are widely used for manufacturing of dyes, pesticides, drugs, pigments, and other industrial products. These compounds have been considered highly toxic to human beings due to their carcinogenic nature. Three groups of aromatic amines have been recognized: monocyclic, polycyclic and heterocyclic aromatic amines. Bacterial degradation of several monocyclic aromatic compounds has been studied in a variety of bacteria, which utilizes monocyclic aromatic amines as their sole source of carbon and energy. Several degradation pathways have been proposed and the related enzymes and genes have also been characterized. Many reviews have been reviewed toxicity of monocyclic aromatic amines; however, there is lack of review on biodegradation of monocyclic aromatic amines. The aim of this review is to summarize bacterial degradation of monocyclic aromatic amines. This review will increase our current understanding of biochemical and molecular basis of bacterial degradation of monocyclic aromatic amines.

  12. Polymeric amines and biomedical uses thereof

    NARCIS (Netherlands)

    Broekhuis, Antonius; Zhang, Youchum; Picchioni, Francesco; Roks, Antonius

    2010-01-01

    The invention relates to the field of polymers and biomedical applications thereof. In particular, it relates to the use of polymeric amines derived from alternating polyketones.Provided is the use of a polymeric amine for modulating or supporting cellular behavior, said polymeric amine being an alt

  13. Biogenic amines in fermented foods

    NARCIS (Netherlands)

    Spano, G.; Russo, P.; Lonvaud-Funel, A.; Lucas, P.; Alexandre, H.; Grandvalet, C.; Coton, E.; Coton, M.; Barnavon, L.; Bach, B.; Rattray, F.; Bunte, A.; Magni, C.; Ladero, V.; Alvarez, M.; Fernández, M.; Lopez, P.; Palencia, P.F. de; Corbi, A.; Trip, H.; Lolkema, J.S.

    2010-01-01

    Food-fermenting lactic acid bacteria (LAB) are generally considered to be non-toxic and non-pathogenic. Some species of LAB, however, can produce biogenic amines (BAs). BAs are organic, basic, nitrogenous compounds, mainly formed through decarboxylation of amino acids. BAs are present in a wide rang

  14. Aminering van hydroxyderivaten van halogeenazahetarenen

    NARCIS (Netherlands)

    Roelfsema, W.A.

    1972-01-01

    In this thesis an introductory investigation is described on the reactivity of hydroxy derivatives of halogenopyridines and a bromohydroxyquinoline towards strong bases.It is a sequel to earlier work on the effect of substituents present in the nucleus of halogenopyridines on the course of amination

  15. Advances in heterocyclic ketene aminals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Recent developments in the study of the reactions of heterocyclic ketene aminals are reviewed with the emphases on regioselective alkylation, acylation and glycosylation reactions, and on the aza-ene reactions with α,β-unsaturated compounds, azo and carbonyl compounds. Reactions with 1,3-dipoles and other reagents to synthesize fused heterocycles are also discussed.

  16. Metabolism of an alkyl polyamine analog by a polyamine oxidase from the microsporidian Encephalitozoon cuniculi.

    Science.gov (United States)

    Bacchi, Cyrus J; Yarlett, Nigel; Faciane, Evangeline; Bi, Xiangdong; Rattendi, Donna; Weiss, Louis M; Woster, Patrick M

    2009-06-01

    Encephalitozoon cuniculi is a microsporidium responsible for systemic illness in mammals. In the course of developing leads to new therapy for microsporidiosis, we found that a bis(phenylbenzyl)3-7-3 analog of spermine, 1,15-bis{N-[o-(phenyl)benzylamino}-4,12-diazapentadecane (BW-1), was a substrate for an E. cuniculi amine oxidase activity. The primary natural substrate for this oxidase activity was N'-acetylspermine, but BW-1 had activity comparable to that of the substrate. As the sole substrate, BW-1 gave linear reaction rates over 15 min and K(m) of 2 microM. In the presence of N'-acetylspermine, BW-1 acted as a competitive inhibitor of oxidase activity and may be a subversive substrate, resulting in increased peroxide production. By use of (13)C-labeled BW-1 as a substrate and nuclear magnetic resonance analysis, two products were determined to be oxidative metabolites, a hydrated aldehyde or dicarboxylate and 2(phenyl)benzylamine. These products were detected after exposure of (13)C-labeled BW-1 to E. cuniculi preemergent spore preparations and to uninfected host cells. In previous studies, BW-1 was curative in a rodent model of infection with E. cuniculi. The results in this study demonstrate competitive inhibition of oxidase activity by BW-1 and support further studies of this oxidase activity by the parasite and host.

  17. Lysyl oxidase in colorectal cancer

    DEFF Research Database (Denmark)

    Cox, Thomas R; Erler, Janine T

    2013-01-01

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

  18. Selective copper catalysed aromatic N-arylation in water

    DEFF Research Database (Denmark)

    Engel-Andreasen, Jens; Shimpukade, Bharat; Ulven, Trond.

    2013-01-01

    4,7-Dipyrrolidinyl-1,10-phenanthroline (DPPhen) was identified as an efficient ligand for copper catalyzed selective arom. N-arylation in water. N-Arylation of indoles, imidazoles and purines proceeds with moderate to excellent yields and complete selectivity over aliph. amines. Aq. medium...

  19. Surface characterization and direct bioelectrocatalysis of multicopper oxidases

    Energy Technology Data Exchange (ETDEWEB)

    Ivnitski, Dmitri M., E-mail: ivnitski@unm.ed [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States)] [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States); Khripin, Constantine [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States); Luckarift, Heather R. [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States)] [Universal Technology Corporation, 1270 N. Fairfield Road, Dayton, OH 45432 (United States); Johnson, Glenn R. [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States); Atanassov, Plamen, E-mail: plamen@unm.ed [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States)

    2010-10-01

    Multicopper oxidases (MCO) have been extensively studied as oxygen reduction catalysts for cathodic reactions in biofuel cells. Theoretically, direct electron transfer between an enzyme and electrode offers optimal energy conversion efficiency providing that the enzyme/electrode interface can be engineered to establish efficient electrical communication. In this study, the direct bioelectrocatalysis of three MCO (Laccase from Trametes versicolor, bilirubin oxidase (BOD) from the fungi Myrothecium verrucaria and ascorbate oxidase (AOx) from Cucurbita sp.) was investigated and compared as oxygen reduction catalysts. Protein film voltammetry and electrochemical characterization of the MCO electrodes showed that DET had been successfully established in all cases. Atomic force microscopy imaging and force measurements indicated that enzyme was immobilized as a monolayer on the electrode surface. Evidence for three clearly separated anodic and cathodic redox events related to the Type 1 (T1) and the trinculear copper centers (T2, T3) of various MCO was observed. The redox potential of the T1 center was strongly modulated by physiological factors including pH, anaerobic and aerobic conditions and the presence of inhibitors.

  20. One step gold (bio)functionalisation based on CS{sub 2}-amine reaction

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ines [Centro de Quimica e Bioquimica, Faculdade de Ciencias da Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa (Portugal); Cascalheira, Antonio C. [Lumisense, Lda, Campus Faculdade de Ciencias da Universidade de Lisboa, Ed. ICAT, Campo Grande, 1749-016 Lisboa (Portugal); Viana, Ana S., E-mail: anaviana@fc.ul.p [Centro de Quimica e Bioquimica, Faculdade de Ciencias da Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa (Portugal)

    2010-12-01

    Dithiocarbamates have been regarded as alternative anchor groups to thiols on gold surfaces, and claimed to be formed in situ through the reaction between secondary amines and carbon disulphide. In this paper, we further exploit this methodology for a convenient one step biomolecule immobilisation onto gold surfaces. First, the reactivity between CS{sub 2} and electroactive compounds containing amines, primary (dopamine), secondary (epinephrine), and an amino acid (tryptophan) has been investigated by electrochemical methods. Cyclic voltammetric characterisation of the modified electrodes confirmed the immobilisation of all the target compounds, allowing the estimation of their surface concentration. The best result was obtained with epinephrine, a secondary amine, for which a typical quasi-reversible behaviour of surface confined electroactive species could be clearly depicted. Electrochemical reductive desorption studies enabled to infer on the extent of the reaction and on the relative stability of the generated monolayers. Bio-functionalisation studies have been accomplished through the reaction of CS{sub 2} with glucose oxidase in aqueous medium, and the catalytic activity of the immobilised enzyme was evaluated towards glucose, by electrochemical methods in the presence of a redox mediator. Scanning tunnelling microscopy (STM) and Atomic force microscopy (AFM) were used respectively, to characterize the gold electrodes and Glucose Oxidase coverage and distribution on the modified surfaces.

  1. Expression of alternative oxidase in tomato

    Energy Technology Data Exchange (ETDEWEB)

    Kakefuda, M.; McIntosh, L. (Michigan State Univ., East Lansing (USA))

    1990-05-01

    Tomato fruit ripening is characterized by an increase in ethylene biosynthesis, a burst in respiration (i.e. the climacteric), fruit softening and pigmentation. As whole tomatoes ripened from mature green to red, there was an increase in the alternative oxidase capacity. Aging pink tomato slices for 24 and 48 hrs also showed an increase of alternative oxidase and cytochrome oxidase capacities. Monoclonal antibodies prepared to the Sauromatum guttatum alternative oxidase were used to follow the appearance of alternative oxidase in tomato fruits. There is a corresponding increase in a 36kDa protein with an increase in alternative oxidase capacity. Effects of ethylene and norbornadiene on alternative oxidase capacity were also studied. We are using an alternative oxidase cDNA clone from potato to study the expression of mRNA in ripening and wounded tomatoes to determine if the gene is transcriptionally regulated.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-01-01

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

  3. Pentamines as substrate for human spermine oxidase

    Science.gov (United States)

    Takao, Koichi; Shirahata, Akira; Samejima, Keijiro; Casero, Robert A.; Igarashi, Kazuei; Sugita, Yoshiaki

    2013-01-01

    Substrate activities of various linear polyamines to human spermine oxidase (hSMO) were investigated. The activities were evaluated by monitoring the amount of H2O2 released from sample polyamines by hSMO. H2O2 was measured by a HPLC method that analyzed fluorescent dimers derived from the oxidation of homovanillic acid in the presence of horseradish peroxidase. Six triamines were tested and were found not to be hSMO substrates. Of sixteen tetramines tested, spermine (Spm) was the most active substrate, followed by homospermine and N-butylated Spm. Pentamines showed a characteristic pattern of substrate activity. Of thirteen pentamines tested, 3343 showed higher substrate activity than Spm, and 4343 showed similar activity to Spm. The activities of the other pentamines were as follows: 3443, 4443, 4344, 3344, 4334, 4444, and 3334 (in decreasing order). Product amines released from these pentamines by hSMO were then analyzed by HPLC. Triamine was the only observed product, and the amount of triamine was nearly equivalent to that of released H2O2. A marked difference in the pH dependency curves between tetramines and pentamines suggested that hSMO favored reactions with a non-protonated secondary nitrogen at the cleavage site. The Km and Vmax values for Spm and 3343 at pH 7.0 and 9.0 were consistent with the higher substrate activity of 3343 compared to Spm, as well as with the concept of a non-protonated secondary nitrogen at the cleavage site being preferred, and 3343 was well degraded at a physiological pH by hSMO. PMID:23449327

  4. Flavoprotein oxidases : classification and applications

    NARCIS (Netherlands)

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

    2013-01-01

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

  5. ADP competes with FAD binding in putrescine oxidase.

    Science.gov (United States)

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

    2008-10-17

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

  6. Biogenic Amines in Insect Antennae

    Directory of Open Access Journals (Sweden)

    Marianna I. Zhukovskaya

    2017-06-01

    Full Text Available Insect antenna is a multisensory organ, each modality of which can be modulated by biogenic amines. Octopamine (OA and its metabolic precursor tyramine (TA affect activity of antennal olfactory receptor neurons. There is some evidence that dopamine (DA modulates gustatory neurons. Serotonin can serve as a neurotransmitter in some afferent mechanosensory neurons and both as a neurotransmitter and neurohormone in efferent fibers targeted at the antennal vessel and mechanosensory organs. As a neurohormone, serotonin affects the generation of the transepithelial potential by sensillar accessory cells. Other possible targets of biogenic amines in insect antennae are hygro- and thermosensory neurons and epithelial cells. We suggest that the insect antenna is partially autonomous in the sense that biologically active substances entering its hemolymph may exert their effects and be cleared from this compartment without affecting other body parts.

  7. Purification and spectroscopic studies on catechol oxidase from lemon balm (Melissa officinalis).

    Science.gov (United States)

    Rompel, Annette; Büldt-Karentzopoulos, Klaudia; Molitor, Christian; Krebs, Bernt

    2012-09-01

    A catechol oxidase from lemon balm (Melissa officinalis) moCO which only catalyzes the oxidation of catechols to quinones without hydroxylating tyrosine was purified. The molecular mass of the M. officinalis enzyme of 39,370 Da was obtained by MALDI mass spectrometry and the isoelectric point was determined to be 3.4. Addition of 2 eq. H(2)O(2) to the enzyme leads to oxy catechol oxidase. In the UV/Vis spectrum two new absorption bands occur at 343 nm (ε=8510 M(-1)cm(-1)) and 580 nm (ε=580 M(-1)cm(-1)) due to O(2)(2-)Cu (II) charge transfer transitions in accordance with the oxy forms of other type 3 copper proteins. The N-terminal sequence has been determined by Edman degradation to NPVQAPELDKCGTAT, exhibiting a proline at the second and sixth position conserved in other polyphenol oxidases. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. A Novel Redox State Heme a Marker in Cytochrome c Oxidase Revealed by Raman Spectroscopy

    Science.gov (United States)

    Piccoli, C.; Perna, G.; Scrima, R.; Cela, O.; Rinaldi, R.; Boffoli, D.; Capozzi, V.; Capitanio, N.

    2005-01-01

    This study was aimed to characterize by Raman spectroscopy (excitation line 633 nm) different redox states of the mitochondrial cytochrome c oxidase. The results obtained from a systematic analysis carried out on the mitochondrial enzyme prepared under redox conditions, differently affecting the valence state of the metal prosthetic groups, and a comparison with homologous bacterial heme-copper oxidases, cytochrome c and pyridine hemo-chrome extract revealed a novel redox state marker specifically linked to the redox transition of heme a, peaking at 1645 cm-1, and tentatively assigned to the C=C and/or C=N streching mode of the imidazole ring of a proxymal histidine ligand. The possible involvment of this redox-linked conformational change in the catalytic activity of cytochrome oxidase is discussed.

  9. Chromate reduction by rabbit liver aldehyde oxidase

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-05-29

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

  10. NCBI nr-aa BLAST: CBRC-BTAU-01-2292 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-BTAU-01-2292 ref|NP_849263.1| amine oxidase, copper containing 2 (retina-speci...fic) [Mus musculus] gb|AAK58864.2|AF350445_1 retina-specific amine oxidase [Mus musculus] emb|CAM19554.1| am...ine oxidase, copper containing 2 (retina-specific) [Mus musculus] NP_849263.1 0.0 80% ...

  11. Replacement of a terminal cytochrome c oxidase by ubiquinol oxidase during the evolution of acetic acid bacteria.

    Science.gov (United States)

    Matsutani, Minenosuke; Fukushima, Kota; Kayama, Chiho; Arimitsu, Misato; Hirakawa, Hideki; Toyama, Hirohide; Adachi, Osao; Yakushi, Toshiharu; Matsushita, Kazunobu

    2014-10-01

    The bacterial aerobic respiratory chain has a terminal oxidase of the heme-copper oxidase superfamily, comprised of cytochrome c oxidase (COX) and ubiquinol oxidase (UOX); UOX evolved from COX. Acetobacter pasteurianus, an α-Proteobacterial acetic acid bacterium (AAB), produces UOX but not COX, although it has a partial COX gene cluster, ctaBD and ctaA, in addition to the UOX operon cyaBACD. We expressed ctaB and ctaA genes of A. pasteurianus in Escherichia coli and demonstrated their function as heme O and heme A synthases. We also found that the absence of ctaD function is likely due to accumulated mutations. These COX genes are closely related to other α-Proteobacterial COX proteins. However, the UOX operons of AAB are closely related to those of the β/γ-Proteobacteria (γ-type UOX), distinct from the α/β-Proteobacterial proteins (α-type UOX), but different from the other γ-type UOX proteins by the absence of the cyoE heme O synthase. Thus, we suggest that A. pasteurianus has a functional γ-type UOX but has lost the COX genes, with the exception of ctaB and ctaA, which supply the heme O and A moieties for UOX. Our results suggest that, in AAB, COX was replaced by β/γ-Proteobacterial UOX via horizontal gene transfer, while the COX genes, except for the heme O/A synthase genes, were lost. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. A two-subunit cytochrome c oxidase (cytochrome aa3) from Paracoccus dentrificans.

    OpenAIRE

    Ludwig, B.; Schatz, G

    1980-01-01

    Cytochrome c oxidase (ferrocytochrome c: oxygen oxidoreductase, EC 1.9.3.1) was purified from the cytoplasmic membrane of the bacterium Paracoccus denitrificans. The enzyme contains two heme groups (a and a3) and two copper atoms per minimal unit, oxidizes mammalian cytochrome c at a high rate, and, when incorporated into liposomes, generates an electrochemical proton gradient during cytochrome c oxidation. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis reveals only two subunits of...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-07-01

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

  14. Biologically active amines in fermented and non-fermented commercial soybean products from the Spanish market.

    Science.gov (United States)

    Toro-Funes, N; Bosch-Fuste, J; Latorre-Moratalla, M L; Veciana-Nogués, M T; Vidal-Carou, M C

    2015-04-15

    Biologically active amines were determined in commercial soybean products. The antioxidant polyamines were found in both non-fermented and fermented soybean products. Natto and tempeh showed the highest content of polyamines (75-124 and 11-24 mg/kg of spermidine and spermine, respectively). On the other hand, the bacterial-related biogenic amines, tyramine, histamine, tryptamine and β-phenylethylamine, were detected in practically all fermented products with a high variability. The highest contents were found in sufu, tamari and soybean paste. Extremely high tyramine and histamine contents, 1700 and 700 mg/kg, respectively, found in some sufu samples could be unhealthy. However, biogenic amines observed in the other soybean products should not be a risk for healthy consumers. However, individuals who take monoamine and diamine oxidase inhibitors drugs should be strongly recommended to avoid this kind of products in order to suffer no adverse health effects. These biogenic amines were not detected in non-fermented soybean products.

  15. Bonding and structure of copper nitrenes.

    Science.gov (United States)

    Cundari, Thomas R; Dinescu, Adriana; Kazi, Abul B

    2008-11-03

    Copper nitrenes are of interest as intermediates in the catalytic aziridination of olefins and the amination of C-H bonds. However, despite advances in the isolation and study of late-transition-metal multiply bonded complexes, a bona fide structurally characterized example of a terminal copper nitrene has, to our knowledge, not been reported. In anticipation of such a report, terminal copper nitrenes are studied from a computational perspective. The nitrene complexes studied here are of the form (beta-diketiminate)Cu(NPh). Density functional theory (DFT), complete active space self-consistent-field (CASSCF) electronic structure techniques, and hybrid quantum mechanical/molecular mechanical (QM/MM) methods are employed to study such species. While DFT methods indicate that a triplet (S = 1) is the ground state, CASSCF calculations indicate that a singlet (S = 0) is the ground state, with only a small energy gap between the singlet and triplet. Moreover, the ground-state (open-shell) singlet copper nitrene is found to be highly multiconfigurational (i.e., biradical) and to possess a bent geometry about the nitrene nitrogen, contrasting with the linear nitrene geometry of the triplet copper nitrenes. CASSCF calculations also reveal the existence of a closed-shell singlet state with some degree of multiple bonding character for the copper-nitrene bond.

  16. Iridium-Catalyzed Condensation of Primary Amines To Form Secondary Amines

    DEFF Research Database (Denmark)

    Lorentz-Petersen, Linda Luise Reeh; Jensen, Paw; Madsen, Robert

    2009-01-01

    Symmetric secondary amines are readily obtained by heating a neat primary amine with 0.5 mol% of bis(dichloro[eta(5)-pentamethylcyclopentadienyl]iridium). The products are isolated by direct distillation in good yields....

  17. Lysyl oxidase in cancer research.

    Science.gov (United States)

    Perryman, Lara; Erler, Janine T

    2014-01-01

    Metastasis is the main reason for cancer-associated deaths and therapies are desperately needed to target the progression of cancer. Lysyl oxidase (LOX) plays a pivotal role in cancer progression, including metastasis, and is therefore is an attractive therapeutic target. In this review we will breakdown the process of cancer progression and the various roles that LOX plays has in the advancement of cancer. We will highlight why LOX is an exciting therapeutic target for the future.

  18. Trace Amines and the Trace Amine-Associated Receptor 1: Pharmacology, Neurochemistry, and Clinical Implications

    OpenAIRE

    Yue ePei; Aman eAsif-Malik; Canales, Juan J.

    2016-01-01

    Biogenic amines are a collection of endogenous molecules that play pivotal roles as neurotransmitters and hormones. In addition to the “classical” biogenic amines resulting from decarboxylation of aromatic acids, including dopamine (DA), norepinephrine, epinephrine, serotonin (5-HT), and histamine, other biogenic amines, present at much lower concentrations in the central nervous system (CNS), and hence referred to as “trace” amines (TAs), are now recognized to play significant neurophysiolog...

  19. Flotation of kaolinite with dodecyl tertiary amines

    Institute of Scientific and Technical Information of China (English)

    CAO Xue-feng; LIU Chang-miao; HU Yue-hua

    2009-01-01

    The flotation of kaolinite using a series of tertiary amines (N,N-dimethyl-dodecyl amine (DRN), N,N-diethyl-dodecyl amine (DEN), N,N-dipropyl-dodecyl amine (DPN) and N,N-dibenzyl-bodecyi amine (DBN)) was investigated. The results show that the maximum recoveries of kaolinite for DEN, DPN and DRN are 93%, 88% and 84%, respectively, but that of DBN is very low. On the basis of zeta potential and FT-IR spectra, the ionization of surface hydroxyl and isomorphic exchange of surface ions account for the charging mechanisms of kaolinite surface. The adsorption mechanism of tertiary amines on kaolinite surface is mainly electrostatic. The isoelectric point (IEP) of kaolinite increases from 3.4 to some more positive points after the interaction of kaolinite with the four tertiary amines. The FT-IR spectra of kaolinite change with the presence of some new sharp shapes belonging to the tertiary amines. The inductive electronic effects and space-steric effects of -CH_3, -C_2H_5, -C_3H_7 and -C_7H_7 bonding to N atom result in different collecting power of the four tertiary amines.

  20. A novel scenario for the evolution of haem-copper oxygen reductases.

    Science.gov (United States)

    Pereira, M M; Santana, M; Teixeira, M

    2001-06-01

    The increasing sequence information on oxygen reductases of the haem-copper superfamily, together with the available three-dimensional structures, allows a clear identification of their common, functionally important features. Taking into consideration both the overall amino acid sequences of the core subunits and key residues involved in proton transfer, a novel hypothesis for the molecular evolution of these enzymes is proposed. Three main families of oxygen reductases are identified on the basis of common features of the core subunits, constituting three lines of evolution: (i) type A (mitochondrial-like oxidases), (ii) type B (ba3-like oxidases) and (iii) type C (cbb3-type oxidases). The first group can be further divided into two subfamilies, according to the helix VI residues at the hydrophobic end of one of the proton pathways (the so-called D-channel): (i) type A1, comprising the enzymes with a glutamate residue in the motif -XGHPEV-, and (ii) type A2, enzymes having instead a tyrosine and a serine in the alternative motif -YSHPXV-. This second subfamily of oxidases is shown to be ancestor to the one containing the glutamate residue, which in the Bacteria domain is only present in oxidases from Gram-positive or purple bacteria. It is further proposed that the Archaea domain acquired terminal oxidases by gene transfer from the Gram-positive bacteria, implying that these enzymes were not present in the last common ancestor before the divergence between Archaea and Bacteria. In fact, most oxidases from archaea have a higher amino acid sequence identity and similarity with those from bacteria, mainly from the Gram-positive group, than with oxidases from other archaea. Finally, a possible relation between the dihaemic subunit (FixP) of the cbb3 oxidases and subunit II of caa3 oxidases is discussed. As the families of haem-copper oxidases can also be identified by their subunit II, a parallel evolution of subunits I and II is suggested.

  1. Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoylhydroxylamines

    Directory of Open Access Journals (Sweden)

    Brett N. Hemric

    2016-01-01

    Full Text Available This paper reports a novel approach for the direct and facile synthesis of 1,2-oxyamino moieties via an intermolecular copper-catalyzed oxyamination of olefins. This strategy utilizes O-benzoylhydroxylamines as an electrophilic amine source and carboxylic acids as a nucleophilic oxygen source to achieve a modular difunctionalization of olefins. The reaction proceeded in a regioselective manner with moderate to good yields, exhibiting a broad scope of carboxylic acid, amine, and olefin substrates.

  2. Role of copper in the process of spermatogenesis

    Directory of Open Access Journals (Sweden)

    Mateusz Ogórek

    2017-08-01

    Full Text Available Copper (Cu is an essential trace element required for the normal development of living organisms. Due to its redox potential, copper is a cofactor in many enzymes responsible for important processes in cells. Copper deficiency has a significant influence on the reduction or the total eradication of copper-dependent enzymes in the body, thereby inhibiting cell life processes. On the other hand, copper is a very reactive element and in its free state, it can trigger the production of large amounts of free radicals, which will consequently lead to the damage of proteins and DNA. Because of those reasons, living organisms have developed precise mechanisms regulating the concentration of copper in cells. Copper also plays a very important role in male fertility. It is an essential element for the production of male gametes. The significant role of copper is also described in the processes of cell division – mitotic and meiotic. Copper-dependent enzymes such as ceruloplasmin, superoxide dismutase SOD1 and SOD3, group of metallothionein and cytochrome c oxidase are present at all stages of gametogenesis as well as in the somatic cells of the testis and in the somatic cells of epididymis. Substantial amounts of copper can also be found in liquids associated with sperm in the epididymis and prostate. Copper also affects the integral androgen distribution in terms of fertility on the line hypothalamic-pituitary-testis. Both copper increase and deficiency leads to a significant reduction in male fertility, which spans the entire spectrum of abnormalities at the sperm level, male gonad, production of hormones and distribution of micronutrients such as zinc and iron. Nowadays, the effects of copper on gametes production have become more important and are connected with the increasing levels of pollution with heavy metals in environment.

  3. The terminal oxidases of Paracoccus denitrificans

    OpenAIRE

    de Gier, Jan-Willem L.; Lübben, Mathias; Reijnders, Willem N.M.; Tipker, Corinne A.; Slotboom, Dirk-Jan; Van Spanning, Rob J. M.; Stouthamer, Adriaan H.; van der Oost, John

    1994-01-01

    Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit I of the aa3-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to complement a double mutant (ΔctaDI, ΔctaDII), indicating that they are isoforms of subunit I of the aa3-type oxidase. The genomic locus of a quinol oxidase has been isolated: cyoABC. This protohaem...

  4. Palladium-catalyzed amination of allyl alcohols.

    Science.gov (United States)

    Ghosh, Raju; Sarkar, Amitabha

    2011-10-21

    An efficient catalytic amination of aryl-substituted allylic alcohols has been developed. The complex [(η(3)-allyl)PdCl](2) modified by a bis phosphine ligand, L, has been used as catalyst in the reaction that afforded a wide range of allyl amines in good to excellent yield under mild conditions.

  5. Method for the production of primary amines

    NARCIS (Netherlands)

    Baldenius, Kai-Uwe; Ditrich, Klaus; Breurer, Michael; Navickas, Vaidotas; Janssen, Dick; Crismaru, Ciprian; Bartsch, Sebastian

    2014-01-01

    The present invention relates to a novel enzymatically catalyzed method for the production of aliphatic primary amines, which method comprises the enzymatic oxidation of a primary aliphatic alcohol catalyzed by an alcohol dehydrogenase, amination of the resulting oxocompound catalyzed by a transamin

  6. Intolerance to dietary biogenic amines : a review

    NARCIS (Netherlands)

    Jansen, SC; van Dusseldorp, M; Bottema, KC; Dubois, AEJ

    2003-01-01

    Objective: To evaluate the scientific evidence for purported intolerance to dietary biogenic amines. Data Sources: MEDLINE was searched for articles in the English language published between January 1966 and August 2001. The keyword biogenic amin* was combined with hypersens*, allergen intoler*, and

  7. Intolerance to dietary biogenic amines: A review

    NARCIS (Netherlands)

    Jansen, S.C.; Dusseldorp, M. van; Bottema, K.C.; Dubois, A.E.J.

    2003-01-01

    Objective: To evaluate the scientific evidence for purported intolerance to dietary biogenic amines. Data Sources: MEDLINE was searched for articles in the English language published between January 1966 and August 2001. The keyword biogenic amin* was combined with hypersens*, allerg*, intoler*, and

  8. Intolerance to dietary biogenic amines : a review

    NARCIS (Netherlands)

    Jansen, SC; van Dusseldorp, M; Bottema, KC; Dubois, AEJ

    Objective: To evaluate the scientific evidence for purported intolerance to dietary biogenic amines. Data Sources: MEDLINE was searched for articles in the English language published between January 1966 and August 2001. The keyword biogenic amin* was combined with hypersens*, allergen intoler*, and

  9. Intolerance to dietary biogenic amines: A review

    NARCIS (Netherlands)

    Jansen, S.C.; Dusseldorp, M. van; Bottema, K.C.; Dubois, A.E.J.

    2003-01-01

    Objective: To evaluate the scientific evidence for purported intolerance to dietary biogenic amines. Data Sources: MEDLINE was searched for articles in the English language published between January 1966 and August 2001. The keyword biogenic amin* was combined with hypersens*, allerg*, intoler*, and

  10. Speaking Personally--with Amin Qazi

    Science.gov (United States)

    Ragan, Lawrence

    2016-01-01

    This article provides an interview with Amin Quazi, the founding chief executive officer of Unizin, a university-owned consortium focused on the emerging digital teaching and learning ecosystem. Amin has a bachelor's degree in chemical engineering from The University of Iowa and a master's degree in business administration from the Carlson School…

  11. A targetable fluorescent sensor reveals that copper-deficient SCO1 and SCO2 patient cells prioritize mitochondrial copper homeostasis.

    Science.gov (United States)

    Dodani, Sheel C; Leary, Scot C; Cobine, Paul A; Winge, Dennis R; Chang, Christopher J

    2011-06-08

    We present the design, synthesis, spectroscopy, and biological applications of Mitochondrial Coppersensor-1 (Mito-CS1), a new type of targetable fluorescent sensor for imaging exchangeable mitochondrial copper pools in living cells. Mito-CS1 is a bifunctional reporter that combines a Cu(+)-responsive fluorescent platform with a mitochondrial-targeting triphenylphosphonium moiety for localizing the probe to this organelle. Molecular imaging with Mito-CS1 establishes that this new chemical tool can detect changes in labile mitochondrial Cu(+) in a model HEK 293T cell line as well as in human fibroblasts. Moreover, we utilized Mito-CS1 in a combined imaging and biochemical study in fibroblasts derived from patients with mutations in the two synthesis of cytochrome c oxidase 1 and 2 proteins (SCO1 and SCO2), each of which is required for assembly and metalation of functionally active cytochrome c oxidase (COX). Interestingly, we observe that although defects in these mitochondrial metallochaperones lead to a global copper deficiency at the whole cell level, total copper and exchangeable mitochondrial Cu(+) pools in SCO1 and SCO2 patient fibroblasts are largely unaltered relative to wild-type controls. Our findings reveal that the cell maintains copper homeostasis in mitochondria even in situations of copper deficiency and mitochondrial metallochaperone malfunction, illustrating the importance of regulating copper stores in this energy-producing organelle.

  12. Process requirements of galactose oxidase catalyzed oxidation of alcohols

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard; R. Birmingham, William; Rehn, Gustav

    2015-01-01

    biocatalyst for the oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. However, GOase requires a number of additives to sustain its catalytic function, such as the enzyme catalase for degradation of the byproduct hydrogen peroxide as well as single......-electron oxidants to reactivate the enzyme upon loss of the amino acid radical in its active site. In this work, the addition of catalase, single-electron oxidants, and copper ions was investigated systematically in order to find the minimum concentrations required to obtain a fully active GOase. Furthermore......, it was found that the concentration and type of buffer is essential for the activity of GOase, which was significantly more active in sodium phosphate buffer than in other buffers investigated. Enzyme stability and oxygen requirements are of crucial importance for the implementation of oxidase based processes...

  13. Cooperation between COA6 and SCO2 in COX2 maturation during cytochrome c oxidase assembly links two mitochondrial cardiomyopathies.

    Science.gov (United States)

    Pacheu-Grau, David; Bareth, Bettina; Dudek, Jan; Juris, Lisa; Vögtle, F-Nora; Wissel, Mirjam; Leary, Scot C; Dennerlein, Sven; Rehling, Peter; Deckers, Markus

    2015-06-02

    Three mitochondria-encoded subunits form the catalytic core of cytochrome c oxidase, the terminal enzyme of the respiratory chain. COX1 and COX2 contain heme and copper redox centers, which are integrated during assembly of the enzyme. Defects in this process lead to an enzyme deficiency and manifest as mitochondrial disorders in humans. Here we demonstrate that COA6 is specifically required for COX2 biogenesis. Absence of COA6 leads to fast turnover of newly synthesized COX2 and a concomitant reduction in cytochrome c oxidase levels. COA6 interacts transiently with the copper-containing catalytic domain of newly synthesized COX2. Interestingly, similar to the copper metallochaperone SCO2, loss of COA6 causes cardiomyopathy in humans. We show that COA6 and SCO2 interact and that corresponding pathogenic mutations in each protein affect complex formation. Our analyses define COA6 as a constituent of the mitochondrial copper relay system, linking defects in COX2 metallation to cardiac cytochrome c oxidase deficiency.

  14. Thermodynamics of mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)], E-mail: jagl@termo.uva.es; Mozo, Ismael; Garcia de la Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Riesco, Nicolas [Department of Chemical Engineering, Loughborough University, Loughborough, LE113TU Leicestershire (United Kingdom)

    2008-01-30

    Mixtures with dimethyl or trimethylpyridines and alkane, aromatic compound or 1-alkanol have been examined using different theories: DISQUAC, Flory, the concentration-concentration structure factor, S{sub CC}(0), or the Kirkwood-Buff formalism. DISQUAC represents fairly well the available experimental data, and improves theoretical calculations from Dortmund UNIFAC. Two important effects have been investigated: (i) the effect of increasing the number of methyl groups attached to the aromatic ring of the amine; (ii) the effect of modifying the position of the methyl groups in this ring. The molar excess enthalpy, H{sup E}, and the molar excess volume, V{sup E}, decrease in systems with alkane or methanol as follows: pyridine > 3-methylpyridine > 3,5-dimethylpyridine and pyridine > 2-methylpyridine > 2,4-dimethylpyridine > 2,4,6-trimethylpyridine, which has been attributed to a weakening of the amine-amine interactions in the same sequences. This is in agreement with the relative variation of the effective dipole moment, {mu}-bar, and of the differences between the boiling temperature of a pyridine base and that of the homomorphic alkane. For heptane solutions, the observed H{sup E} variation, H{sup E} (3,5-dimethylpyridine) > H{sup E} (2,4-dimethylpyridine) > H{sup E} (2,6-dimethylpyridine), is explained similarly. Calculations on the basis of the Flory model confirm that orientational effects become weaker in systems with alkane in the order: pyridine > methylpyridine > dimethylpyridine > trimethylpyridine. S{sub CC}(0) calculations show that steric effects increase with the number of CH{sub 3}- groups in the pyridine base, and that the steric effects exerted by methyl groups in positions 2 and 6 are higher than when they are placed in positions 3 and 5. The hydrogen bond energy in methanol mixtures is independent of the pyridine base, and it is estimated to be -35.2 kJ mol{sup -1}. Heterocoordination in these solutions is due in part to size effects. Their

  15. Mussel inspired preparation of amine-functionalized Kaolin for effective removal of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qiang; Liu, Meiying; Deng, Fengjie [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Wang, Ke [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China); Huang, Hongye; Xu, Dazhuang; Zeng, Guangjian [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Wei, Yen [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China)

    2016-09-15

    Adsorption has been well regarded as a promising and efficient method for the removal of low concentration heavy metal ions in aqueous solutions. And kaolin has been considered as a kind of low cost and environment-friendly adsorbent for its abundant in nature. But the low adsorption capacity to heavy metal ions and severe aggregation in solution restrains its application. In this work, an environment-friendly adsorbent (denoted as Kaolin-PDA-PEI) was prepared based on mussel inspired chemistry and Michael addition reaction between high reaction activity of polydopamine (PDA) and polyethyleneimine (PEI), which was possesses a number of amine groups. The amine groups have displayed strong adsorption affinity towards copper ions. The successful modification of Kaolin by PDA and PEI was confirmed by a series of analyses, such as Fourier transform infrared spectroscopy, transmission electron microscopy, thermal gravimetry analysis and X-ray photoelectron spectroscopy. The effects of various parameters such as contact time, pH, initial concentrations of copper ions and temperature on copper ion adsorption by Kaolin-PDA-PEI were investigated. Kaolin-PDA-PEI shows higher adsorption capacity as compared with the raw Kaolin. The kinetic adsorption data were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion model. The Langmuir isotherm and Freundlich isotherm equilibrium model were applied to adsorption isotherm data to find the better fit isotherm. The results showed that adsorption process was well fitted by Langmuir isotherm model. The values of thermodynamics constants such as entropy change (ΔS{sup 0}), enthalpy change (ΔH{sup 0}) and Gibbs free energy (ΔG{sup 0}) were also calculated. The results indicated that the adsorption process of Kaolin-PDA-PEI were endothermic and spontaneous. - Graphical abstract: Amino groups functionalized Kaolin was facilely prepared via mussel inspired chemistry. The modified Kaolin exhibited much

  16. Mitochondrial cytochrome c oxidase deficiency.

    Science.gov (United States)

    Rak, Malgorzata; Bénit, Paule; Chrétien, Dominique; Bouchereau, Juliette; Schiff, Manuel; El-Khoury, Riyad; Tzagoloff, Alexander; Rustin, Pierre

    2016-03-01

    As with other mitochondrial respiratory chain components, marked clinical and genetic heterogeneity is observed in patients with a cytochrome c oxidase deficiency. This constitutes a considerable diagnostic challenge and raises a number of puzzling questions. So far, pathological mutations have been reported in more than 30 genes, in both mitochondrial and nuclear DNA, affecting either structural subunits of the enzyme or proteins involved in its biogenesis. In this review, we discuss the possible causes of the discrepancy between the spectacular advances made in the identification of the molecular bases of cytochrome oxidase deficiency and the lack of any efficient treatment in diseases resulting from such deficiencies. This brings back many unsolved questions related to the frequent delay of clinical manifestation, variable course and severity, and tissue-involvement often associated with these diseases. In this context, we stress the importance of studying different models of these diseases, but also discuss the limitations encountered in most available disease models. In the future, with the possible exception of replacement therapy using genes, cells or organs, a better understanding of underlying mechanism(s) of these mitochondrial diseases is presumably required to develop efficient therapy.

  17. Quantifying amine permeation sources with acid neutralization: calibrations and amines measured in coastal and continental atmospheres

    Directory of Open Access Journals (Sweden)

    N. A. Freshour

    2014-04-01

    Full Text Available An acid titration method for quantifying amine permeation rates was used to calibrate an Ambient pressure Proton transfer Mass Spectrometer (AmPMS that monitors ambient amine compounds. The method involves capturing amines entrained in a N2 flow by bubbling it through an acidified solution (~ 10−5 M HCl, and the amines are quantified via changes in solution pH with time. Home-made permeation tubes had permeation rates (typically tens of pmol s−1 that depended on the type of amine and tubing and on temperature. Calibrations of AmPMS yielded sensitivities for ammonia, methyl amine, dimethyl amine, and trimethyl amine that are close to the sensitivity assuming a gas-kinetic, ion-molecule rate coefficient. The permeation tubes were also designed to deliver a reproducible amount of amine to a flow reactor where nucleation with sulfuric acid was studied. The high proton affinity compound dimethyl sulfoxide (DMSO, linked to oceanic environments, was also studied and AmPMS is highly sensitive to it. AmPMS was deployed recently in two field campaigns and mixing ratios are reported for ammonia, alkyl amines, and DMSO and correlations between these species and with particle formation events are discussed.

  18. Genomic organisation, activity and distribution analysis of the microbial putrescine oxidase degradation pathway.

    Science.gov (United States)

    Foster, Alexander; Barnes, Nicole; Speight, Robert; Keane, Mark A

    2013-10-01

    The catalytic action of putrescine specific amine oxidases acting in tandem with 4-aminobutyraldehyde dehydrogenase is explored as a degradative pathway in Rhodococcus opacus. By limiting the nitrogen source, increased catalytic activity was induced leading to a coordinated response in the oxidative deamination of putrescine to 4-aminobutyraldehyde and subsequent dehydrogenation to 4-aminobutyrate. Isolating the dehydrogenase by ion exchange chromatography and gel filtration revealed that the enzyme acts principally on linear aliphatic aldehydes possessing an amino moiety. Michaelis-Menten kinetic analysis delivered a Michaelis constant (K(M)=0.014 mM) and maximum rate (Vmax=11.2 μmol/min/mg) for the conversion of 4-aminobutyraldehyde to 4-aminobutyrate. The dehydrogenase identified by MALDI-TOF mass spectrometric analysis (E value=0.031, 23% coverage) belongs to a functionally related genomic cluster that includes the amine oxidase, suggesting their association in a directed cell response. Key regulatory, stress and transport encoding genes have been identified, along with candidate dehydrogenases and transaminases for the further conversion of 4-aminobutyrate to succinate. Genomic analysis has revealed highly similar metabolic gene clustering among members of Actinobacteria, providing insight into putrescine degradation notably among Micrococcaceae, Rhodococci and Corynebacterium by a pathway that was previously uncharacterised in bacteria.

  19. Consecutive condensation, C-N and N-N bond formations: a copper- catalyzed one-pot three-component synthesis of 2H-indazole.

    Science.gov (United States)

    Kumar, Manian Rajesh; Park, Ahbyeol; Park, Namjin; Lee, Sunwoo

    2011-07-01

    2H-Indazoles are synthesized using copper-catalyzed, one-pot, three-component reactions of 2-bromobenzaldehydes, primary amines, and sodium azide. A copper catalyst plays the key role in the formation of C-N and N-N bonds. This method has a broad substrate scope with a high tolerance for a variety of functional groups.

  20. Cardiac Cytochrome c Oxidase Activity and Contents of Submits 1 and 4 are Altered in Offspring by Low Prenatal Intake by Rat Dams

    Science.gov (United States)

    It has been reported previously that the offspring of rat dams consuming low dietary copper (Cu) during pregnancy and lactation experience a deficiency in cardiac cytochrome c oxidase (CCO) characterized by reduced catalytic activity and mitochondrial- and nuclear-subunit content after postnatal day...

  1. Interaction energies of CO2·amine complexes: effects of amine substituents.

    Science.gov (United States)

    Jorgensen, Kameron R; Cundari, Thomas R; Wilson, Angela K

    2012-10-25

    To focus on the identification of potential alternative amine carbon capture compounds, CO(2) with methyl, silyl, and trifluoromethyl monosubstituted and disubstituted amine compounds were studied. Interaction energies of these CO(2)·amine complexes were determined via two methods: (a) an ab initio composite method, the correlation consistent composite approach (ccCA), to determine interaction energies and (b) density functional theories, B3LYP/aug-cc-pVTZ and B97D/aug-cc-pVTZ. Substituent effects on the interaction energies were examined by interchanging electron donating and electron withdrawing substituents on the amine compounds. The calculations suggested two different binding modes, hydrogen bonding and acid-base interactions, which arise from the modification of the amine substituents, echoing previous work by our group on modeling protein·CO(2) interactions. Recommendations have been noted for the development of improved amine scrubber complexes.

  2. Unfolding pathway of CotA-laccase and the role of copper on the prevention of refolding through aggregation of the unfolded state

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Andre T. [Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Av. da Republica, 2780-157 Oeiras (Portugal); Lopes, Carlos [Centre for Molecular and Structural Biomedicine, Institute for Biotechnology and Bioengineering, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Martins, Ligia O. [Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Av. da Republica, 2780-157 Oeiras (Portugal); Melo, Eduardo Pinho, E-mail: emelo@ualg.pt [Centre for Molecular and Structural Biomedicine, Institute for Biotechnology and Bioengineering, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2012-06-08

    Highlights: Black-Right-Pointing-Pointer CotA-laccase unfolds with an intermediate state. Black-Right-Pointing-Pointer Copper stabilizes the native and the intermediate state. Black-Right-Pointing-Pointer Copper binding to the unfolded state prevents refolding through protein aggregation. Black-Right-Pointing-Pointer Copper incorporation in CotA-laccase occurs as a later step during folding. -- Abstract: Copper is a redox-active metal and the main player in electron transfer reactions occurring in multicopper oxidases. The role of copper in the unfolding pathway and refolding of the multicopper oxidase CotA laccase in vitro was solved using double-jump stopped-flow experiments. Unfolding of apo- and holo-CotA was described as a three-state process with accumulation of an intermediate in between the native and unfolded state. Copper stabilizes the native holo-CotA but also the intermediate state showing that copper is still bound to this state. Also, copper binds to unfolded holo-CotA in a non-native coordination promoting CotA aggregation and preventing refolding to the native structure. These results gather information on unfolding/folding pathways of multicopper oxidases and show that copper incorporation in vivo should be a tight controlled process as copper binding to the unfolded state under native conditions promotes protein aggregation.

  3. Advance in the synthesis of aromatic amine via direct amination

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Arylamines are very common and important organic molecules. Acting as important intermediates in medical and chemical industry, they are widely used in the synthesis of pharmaceuticals, dyes, pesticides, rubber additives, isocyanates and heterocyclic compounds. The traditional methods for the synthesis of arylamines include several steps. The production of aniline, for example, includes the following steps: the production of nitro-benzene by the nitration of benzene, and the reduction of the resulting nitro-benzene by catalytic hydrogenation or other reduction ways[1-6]; or the substitution of phenol or chlorbenzene by amino groups, etc.[7-10]. There are several disadvantages for these methods: low atom utilization, strict operation condition, large amount of by-products and serious environmental pollution, which could not afford for the needs of a sustainable civilization. So there has been growing interest in the direct amination to produce arylamines recently. With the direct methods, the multi- step reaction may change into one step, the atom utilization can be evidently improved, and the by-products H2 or/and H2O are harmless to the environment.

  4. Oxidase-based biocatalytic processes

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Woodley, John; Krühne, Ulrich

    the reaction species (substrate and product volatility for example) and the process (such as oxygen supply, ability to control pH) and are classified as reaction-related and process-related constraintsrespectively. Although the development of biocatalyst and process engineering tools offers a number...... ofsolutions to overcome the limitations, it is often complicated to identify the key limitation of the system that prevents economic scale-up. Hence, development of a systematic method for identifying the limitations during early-stage development of a biocatalytic process and potentially the order in which...... theyneed to be tackled would offer a valuable tool for process development.Biocatalytic oxidationsare potentially of great value because of theselective chemistry that they offer,resulting in higher yieldscompared to thoseachievable through chemical catalysis. Oxidases areparticularly...

  5. Cucumber Seedling Indoleacetaldehyde Oxidase 1

    Science.gov (United States)

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

    1978-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Laurence Prunetti

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

  7. Graphite Oxide and Aromatic Amines : Size Matters

    NARCIS (Netherlands)

    Spyrou, Konstantinos; Calvaresi, Matteo; Diamanti, Evmorfi A. K.; Tsoufis, Theodoros; Gournis, Dimitrios; Rudolf, Petra; Zerbetto, Francesco

    2015-01-01

    Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline

  8. Amines as occupational hazards for visual disturbance

    Science.gov (United States)

    JANG, Jae-Kil

    2015-01-01

    Various amines, such as triethylamine and N,N-dimethylethylamine, have been reported to cause glaucopsia in workers employed in epoxy, foundry, and polyurethane foam industries. This symptom has been related to corneal edema and vesicular collection of fluid within the corneal subepithelial cells. Exposure to amine vapors for 30 min to several hours leads to blurring of vision, a blue-grey appearance of objects, and halos around lights, that are probably reversible. Concentration-effect relationships have been established. The visual disturbance is considered a nuisance, as it could cause onsite accidents, impair work efficiency, and create difficulties in driving back home. Occupational exposure limits have been established for some amines, but there is shortage of criteria. Volatility factors, such as vapor pressure, should be considered in industrial settings to prevent human ocular risks, while trying to reduce levels of hazardous amines in the atmosphere. PMID:26538000

  9. Graphite Oxide and Aromatic Amines : Size Matters

    NARCIS (Netherlands)

    Spyrou, Konstantinos; Calvaresi, Matteo; Diamanti, Evmorfi A. K.; Tsoufis, Theodoros; Gournis, Dimitrios; Rudolf, Petra; Zerbetto, Francesco

    2015-01-01

    Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molec

  10. Reactivity of copper(II)-alkylperoxo complexes.

    Science.gov (United States)

    Tano, Tetsuro; Ertem, Mehmed Z; Yamaguchi, Satoru; Kunishita, Atsushi; Sugimoto, Hideki; Fujieda, Nobutaka; Ogura, Takashi; Cramer, Christopher J; Itoh, Shinobu

    2011-10-28

    Copper(II) complexes 1a and 1b, supported by tridentate ligand bpa [bis(2-pyridylmethyl)amine] and tetradentate ligand tpa [tris(2-pyridylmethyl)amine], respectively, react with cumene hydroperoxide (CmOOH) in the presence of triethylamine in CH(3)CN to provide the corresponding copper(II) cumylperoxo complexes 2a and 2b, the formation of which has been confirmed by resonance Raman and ESI-MS analyses using (18)O-labeled CmOOH. UV-vis and ESR spectra as well as DFT calculations indicate that 2a has a 5-coordinate square-pyramidal structure involving CmOO(-) at an equatorial position and one solvent molecule at an axial position at low temperature (-90 °C), whereas a 4-coordinate square-planar structure that has lost the axial solvent ligand is predominant at higher temperatures (above 0 °C). Complex 2b, on the other hand, has a typical trigonal bipyramidal structure with the tripodal tetradentate tpa ligand, where the cumylperoxo ligand occupies an axial position. Both cumylperoxo copper(II) complexes 2a and 2b are fairly stable at ambient temperature, but decompose at a higher temperature (60 °C) in CH(3)CN. Detailed product analyses and DFT studies indicate that the self-decomposition involves O-O bond homolytic cleavage of the peroxo moiety; concomitant hydrogen-atom abstraction from the solvent is partially involved. In the presence of 1,4-cyclohexadiene (CHD), the cumylperoxo complexes react smoothly at 30 °C to give benzene as one product. Detailed product analyses and DFT studies indicate that reaction with CHD involves concerted O-O bond homolytic cleavage and hydrogen-atom abstraction from the substrate, with the oxygen atom directly bonded to the copper(II) ion (proximal oxygen) involved in the C-H bond activation step.

  11. Insights into proton translocation in cbb3 oxidase from MD simulations.

    Science.gov (United States)

    Carvalheda, Catarina A; Pisliakov, Andrei V

    2017-05-01

    Heme-copper oxidases are membrane protein complexes that catalyse the final step of the aerobic respiration, namely the reduction of oxygen to water. The energy released during catalysis is coupled to the active translocation of protons across the membrane, which contributes to the establishment of an electrochemical gradient that is used for ATP synthesis. The distinctive C-type (or cbb3) cytochrome c oxidases, which are mostly present in proteobacteria, exhibit a number of unique structural and functional features, including high catalytic activity at low oxygen concentrations. At the moment, the functioning mechanism of C-type oxidases, in particular the proton transfer/pumping mechanism presumably via a single proton channel, is still poorly understood. In this work we used all-atom molecular dynamics simulations and continuum electrostatics calculations to obtain atomic-level insights into the hydration and dynamics of a cbb3 oxidase. We provide the details of the water dynamics and proton transfer pathways for both the "chemical" and "pumped" protons, and show that formation of protonic connections is strongly affected by the protonation state of key residues, namely H243, E323 and H337. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Copper allergy from dental copper amalgam?

    Science.gov (United States)

    Gerhardsson, Lars; Björkner, Bert; Karlsteen, Magnus; Schütz, Andrejs

    2002-05-06

    A 65-year-old female was investigated due to a gradually increasing greenish colour change of her plastic dental splint, which she used to prevent teeth grinding when sleeping. Furthermore, she had noted a greenish/bluish colour change on the back of her black gloves, which she used to wipe her tears away while walking outdoors. The investigation revealed that the patient had a contact allergy to copper, which is very rare. She had, however, had no occupational exposure to copper. The contact allergy may be caused by long-term exposure of the oral mucosa to copper from copper-rich amalgam fillings, which were frequently used in childhood dentistry up to the 1960s in Sweden. The deposition of a copper-containing coating on the dental splint may be caused by a raised copper intake from drinking water, increasing the copper excretion in saliva, in combination with release of copper due to electrochemical corrosion of dental amalgam. The greenish colour change of the surface of the splint is probably caused by deposition of a mixture of copper compounds, e.g. copper carbonates. Analysis by the X-ray diffraction technique indicates that the dominant component is copper oxide (Cu2O and CuO). The corresponding greenish/bluish discoloration observed on the back of the patient's gloves may be caused by increased copper excretion in tears.

  13. General Dialdehyde Click Chemistry for Amine Bioconjugation.

    Science.gov (United States)

    Elahipanah, Sina; O'Brien, Paul J; Rogozhnikov, Dmitry; Yousaf, Muhammad N

    2017-05-17

    The development of methods for conjugating a range of molecules to primary amine functional groups has revolutionized the fields of chemistry, biology, and material science. The primary amine is a key functional group and one of the most important nucleophiles and bases used in all of synthetic chemistry. Therefore, tremendous interest in the synthesis of molecules containing primary amines and strategies to devise chemical reactions to react with primary amines has been at the core of chemical research. In particular, primary amines are a ubiquitous functional group found in biological systems as free amino acids, as key side chain lysines in proteins, and in signaling molecules and metabolites and are also present in many natural product classes. Due to its abundance, the primary amine is the most convenient functional group handle in molecules for ligation to other molecules for a broad range of applications that impact all scientific fields. Because of the primary amine's central importance in synthetic chemistry, acid-base chemistry, redox chemistry, and biology, many methods have been developed to efficiently react with primary amines, including activated carboxylic acids, isothiocyanates, Michael addition type systems, and reaction with ketones or aldehydes followed by in situ reductive amination. Herein, we introduce a new traceless, high-yield, fast click-chemistry method based on the rapid and efficient trapping of amine groups via a functionalized dialdehyde group. The click reaction occurs in mild conditions in organic solvents or aqueous media and proceeds in high yield, and the starting dialdehyde reagent and resulting dialdehyde click conjugates are stable. Moreover, no catalyst or dialdehyde-activating group is required, and the only byproduct is water. The initial dialdehyde and the resulting conjugate are both straightforward to characterize, and the reaction proceeds with high atom economy. To demonstrate the broad scope of this new click

  14. Selective N-alkylation of amines using nitriles under hydrogenation conditions: facile synthesis of secondary and tertiary amines.

    Science.gov (United States)

    Ikawa, Takashi; Fujita, Yuki; Mizusaki, Tomoteru; Betsuin, Sae; Takamatsu, Haruki; Maegawa, Tomohiro; Monguchi, Yasunari; Sajiki, Hironao

    2012-01-14

    Nitriles were found to be highly effective alkylating reagents for the selective N-alkylation of amines under catalytic hydrogenation conditions. For the aromatic primary amines, the corresponding secondary amines were selectively obtained under Pd/C-catalyzed hydrogenation conditions. Although the use of electron poor aromatic amines or bulky nitriles showed a lower reactivity toward the reductive alkylation, the addition of NH(4)OAc enhanced the reactivity to give secondary aromatic amines in good to excellent yields. Under the same reaction conditions, aromatic nitro compounds instead of the aromatic primary amines could be directly transformed into secondary amines via a domino reaction involving the one-pot hydrogenation of the nitro group and the reductive alkylation of the amines. While aliphatic amines were effectively converted to the corresponding tertiary amines under Pd/C-catalyzed conditions, Rh/C was a highly effective catalyst for the N-monoalkylation of aliphatic primary amines without over-alkylation to the tertiary amines. Furthermore, the combination of the Rh/C-catalyzed N-monoalkylation of the aliphatic primary amines and additional Pd/C-catalyzed alkylation of the resulting secondary aliphatic amines could selectively prepare aliphatic tertiary amines possessing three different alkyl groups. According to the mechanistic studies, it seems reasonable to conclude that nitriles were reduced to aldimines before the nucleophilic attack of the amine during the first step of the reaction.

  15. Increasing the catalytic activity of Bilirubin oxidase from Bacillus pumilus: Importance of host strain and chaperones proteins.

    Science.gov (United States)

    Gounel, Sébastien; Rouhana, Jad; Stines-Chaumeil, Claire; Cadet, Marine; Mano, Nicolas

    2016-07-20

    Aggregation of recombinant proteins into inclusion bodies (IBs) is the main problem of the expression of multicopper oxidase in Escherichia coli. It is usually attributed to inefficient folding of proteins due to the lack of copper and/or unavailability of chaperone proteins. The general strategies reported to overcome this issue have been focused on increasing the intracellular copper concentration. Here we report a complementary method to optimize the expression in E. coli of a promising Bilirubin oxidase (BOD) isolated from Bacillus pumilus. First, as this BOD has a disulfide bridge, we switched E.coli strain from BL21 (DE3) to Origami B (DE3), known to promote the formation of disulfide bridges in the bacterial cytoplasm. In a second step, we investigate the effect of co-expression of chaperone proteins on the protein production and specific activity. Our strategy allowed increasing the final amount of enzyme by 858% and its catalytic rate constant by 83%.

  16. Aromatic amines sources, environmental impact and remediation

    OpenAIRE

    Pereira,Luciana; Mondal, P. K.; Alves,M. M.

    2015-01-01

    Aromatic amines are widely used industrial chemicals as their major sources in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives, rubbers, perfume, pharmaceuticals, pesticides and explosives. They result also from diesel exhaust, combustion of wood chips and rubber and tobacco smoke. Some types of aromatic amines are generated during cooking, special grilled meat and fish, as well. The intensive use and production of these comp...

  17. Aromatic amines sources, environmental impact and remediation

    OpenAIRE

    Pereira, Luciana; Mondal, P. K.; Alves, M. M.

    2015-01-01

    Aromatic amines are widely used industrial chemicals as their major sources in the environment include several chemical industry sectors such as oil refining, synthetic polymers, dyes, adhesives, rubbers, perfume, pharmaceuticals, pesticides and explosives. They result also from diesel exhaust, combustion of wood chips and rubber and tobacco smoke. Some types of aromatic amines are generated during cooking, special grilled meat and fish, as well. The intensive use and production of these comp...

  18. The fictile coordination chemistry of cuprous-thiolate sites in copper chaperones.

    Science.gov (United States)

    Pushie, M Jake; Zhang, Limei; Pickering, Ingrid J; George, Graham N

    2012-06-01

    Copper plays vital roles in the active sites of cytochrome oxidase and in several other enzymes essential for human health. Copper is also highly toxic when dysregulated; because of this an elaborate array of accessory proteins have evolved which act as intracellular carriers or chaperones for the copper ions. In most cases chaperones transport cuprous copper. This review discusses some of the chemistry of these copper sites, with a view to some of the structural factors in copper coordination which are important in the biological function of these chaperones. The coordination chemistry and accessible geometries of the cuprous oxidation state are remarkably plastic and we discuss how this may relate to biological function. This article is part of a Special Issue entitled: Biogenesis/Assembly of Respiratory Enzyme Complexes.

  19. Laboratory and histological similarities between Wilson's disease and rats with copper toxicity.

    Directory of Open Access Journals (Sweden)

    Narasaki,Mikio

    1980-04-01

    Full Text Available Rats were injected intraperitoneally with copper-lactate daily for over 160 days (total dose of 30 mg copper in each animal. At 120 to 160 days of copper administration, animals developed symptoms similar to those of Wilson's disease, i.e., kidney functional disturbances, proteinuria, aminoaciduria, decreased blood ceruloplasmin oxidase activity and increased urinary copper excretion. Cirrhosis was found in some animals. Tubular necrosis of the kidneys, liver fibrosis and tigrolysis of thalamic nerve cells were also found. Copper depositions were observed in liver parenchymal cells, renal tubular epithels, thalamus glia cells and on the Descemet's membrane of the cornea. The similarities between induced copper- intoxication in rats and Wilson's disease are discussed.

  20. Copper Products Capacity Expansion Stimulate the Copper Consumption

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>The dramatic growth of copper consumption in China can directly be seen from the expansion of copper products capacity.According to sta- tistics,in the past 4 years,the improvement on the balance of trade on copper bar,copper,and copper alloy and copper wire & cable has driven the growth of copper consumption a lot.

  1. $^{111m}$Cd- and $^{199m}$Hg-derivatives of blue oxidases

    CERN Multimedia

    2002-01-01

    The rack-induced bonding concept (H.B.Gray & B.G.~Malmstroem, Comments Inorg. Chem, 2, 203, 1983) postulates that the bound metal ion in metalloproteins is forced to adopt a coordination geometry determined by the rigid peptide conformation of the protein. Alternatively, the metal ion could create its own favoured coordination geometry in a soft peptide conformation. In order to decide who is slave or master the changes of coordination and rigidity of metal sites in blue copper proteins due to metal and ligand exchange were studied by $^{111m}$Cd and $^{199m}$Hg $\\gamma$-$\\gamma$-perturbed angular correlation (PAC). To get a better understanding of the so called " Type 1 Copper Site " of the blue oxidases laccase (LAC) and ascorbate oxidase (AO) we concentrated our investigations on the small blue copper proteins azurin and plastocyanin. \\\\ \\\\In azurin~(Az), the metal ligand methionine 121~(M121) was replaced by several amino acids, e.g. asparagine~(N), glutamic acid~(E), via site directed mutagenesis. Di...

  2. Brain Monoamine Oxidase-A Activity Predicts Trait Aggression

    Science.gov (United States)

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

    2008-01-01

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

  3. Enhancing amine terminals in an amine-deprived collagen matrix.

    LENUS (Irish Health Repository)

    Tiong, William H C

    2008-10-21

    Collagen, though widely used as a core biomaterial in many clinical applications, is often limited by its rapid degradability which prevents full exploitation of its potential in vivo. Polyamidoamine (PAMAM) dendrimer, a highly branched macromolecule, possesses versatile multiterminal amine surface groups that enable them to be tethered to collagen molecules and enhance their potential. In this study, we hypothesized that incorporation of PAMAM dendrimer in a collagen matrix through cross-linking will result in a durable, cross-linked collagen biomaterial with free -NH 2 groups available for further multi-biomolecular tethering. The aim of this study was to assess the physicochemical properties of a G1 PAMAM cross-linked collagen matrix and its cellular sustainability in vitro. Different amounts of G1 PAMAM dendrimer (5 or 10 mg) were integrated into bovine-derived collagen matrices through a cross-linking process, mediated by 5 or 25 mM 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) in 5 mM N-hydroxysuccinimide (NHS) and 50 mM 2-morpholinoethane sulfonic acid buffer at pH 5.5. The physicochemical properties of resultant matrices were investigated with scanning electron microscopy (SEM), collagenase degradation assay, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectra, and ninhydrin assay. Cellular sustainability of the matrices was assessed with Alamar Blue assay and SEM. There was no significant difference in cellular behavior between the treated and nontreated groups. However, the benefit of incorporating PAMAM in the cross-linking reaction was limited when higher concentrations of either agent were used. These results confirm the hypothesis that PAMAM dendrimer can be incorporated in the collagen cross-linking process in order to modulate the properties of the resulting cross-linked collagen biomaterial with free -NH 2 groups available for multi-biomolecular tethering.

  4. Antwerp Copper Plates

    DEFF Research Database (Denmark)

    Wadum, Jørgen

    1999-01-01

    In addition to presenting a short history of copper paintings, topics detail artists’ materials and techniques, as well as aspects of the copper industry, including mining, preparation and trade routes.......In addition to presenting a short history of copper paintings, topics detail artists’ materials and techniques, as well as aspects of the copper industry, including mining, preparation and trade routes....

  5. Modulation of the genotoxicity of bleomycin by amines through noncovalent DNA interactions and alteration of physiological conditions in yeast

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, George R. [Department of Biology, College of the Holy Cross, One College Street, Worcester, MA 01610-2395 (United States)], E-mail: ghoffmann@holycross.edu; Gessner, Gabrielle S.; Hughes, Jennifer F.; Ronan, Matthew V.; Sylvia, Katelyn E.; Willett, Christine J. [Department of Biology, College of the Holy Cross, One College Street, Worcester, MA 01610-2395 (United States)

    2007-10-01

    The effects of amines on the induction of mitotic gene conversion by bleomycin (BLM) were studied at the trp5 locus in Saccharomyces cerevisiae strain D7. BLM induces double-strand breaks in DNA and is a potent recombinagen in this assay. The polyamine spermidine causes concentration-dependent protection against the genotoxicity of BLM, reducing the convertant frequency by over 90% under the most protective conditions. Spermine, diethylenetriamine, ethylenediamine, putrescine, and ethylamine were also antigenotoxic in combined treatments with BLM. There was a general correspondence between the protective effect and the number of amino groups, suggesting that more strongly cationic amines tend to be stronger antirecombinagens. Electrostatic association of the amines with DNA probably hinders BLM access to the 4' position of deoxyribose where it generates a free radical. Other amines interact with BLM differently from these unbranched aliphatic amines. The aminothiol cysteamine inhibits the genotoxicity of BLM under hypoxic conditions but increases it under euoxic conditions. In contrast, pargyline potentiates the genotoxicity of BLM under hypoxic conditions but not under euoxic conditions. The antirecombinagenic effect of cysteamine apparently involves DNA binding and depletion of oxygen needed for BLM activity, whereas its potentiation of BLM entails its serving as an electron source for the activation of BLM. Pargyline may enhance BLM indirectly by preventing the depletion of oxygen by monoamine and polyamine oxidase. The planar 9-aminoacridine weakly induces gene conversion in strain D7, but it is strongly synergistic with BLM. Enhancement of BLM activity by this compound and by the related nitroacridine Entozon is apparently mediated by intercalation of the acridine ring system into DNA. Thus, the influence of amines on the genotoxicity of BLM in yeast encompasses antigenotoxic, potentiating, and synergistic interactions. The underlying mechanisms involve

  6. Reactivity of mononuclear alkylperoxo copper(II) complex. O-O bond cleavage and C-H bond activation.

    Science.gov (United States)

    Kunishita, Atsushi; Ishimaru, Hirohito; Nakashima, Satoru; Ogura, Takashi; Itoh, Shinobu

    2008-04-02

    A detailed reactivity study has been carried out for the first time on a new mononuclear alkylperoxo copper(II) complex, which is generated by the reaction of copper(II) complex supported by the bis(pyridylmethyl)amine tridentate ligand containing a phenyl group at the 6-position of the pyridine donor groups and cumene hydroperoxide (CmOOH) in CH3CN. The cumylperoxo copper(II) complex thus obtained has been found to undergo homolytic cleavage of the O-O bond and induce C-H bond activation of exogenous substrates, providing important insights into the catalytic mechanism of copper monooxygenases.

  7. COX19 mediates the transduction of a mitochondrial redox signal from SCO1 that regulates ATP7A-mediated cellular copper efflux

    OpenAIRE

    Leary, Scot C; Cobine, Paul A.; Nishimura, Tamiko; Verdijk, Robert M; de Krijger, Ronald; Coo, René; Tarnopolsky, Mark A.; Winge, Dennis R; Eric A Shoubridge

    2013-01-01

    SCO1 and SCO2 are metallochaperones whose principal function is to add two copper ions to the catalytic core of cytochrome c oxidase (COX). However, affected tissues of SCO1 and SCO2 patients exhibit a combined deficiency in COX activity and total copper content, suggesting additional roles for these proteins in the regulation of cellular copper homeostasis. Here we show that both the redox state of the copper-binding cysteines of SCO1 and the abundance of SCO2 correlate with cellular copper ...

  8. Electrocatalytic O2 Reduction at a Bio-inspired Mononuclear Copper Phenolato Complex Immobilized on a Carbon Nanotube Electrode.

    Science.gov (United States)

    Gentil, Solène; Serre, Doti; Philouze, Christian; Holzinger, Michael; Thomas, Fabrice; Le Goff, Alan

    2016-02-12

    An original copper-phenolate complex, mimicking the active center of galactose oxidase, featuring a pyrene group was synthesized. Supramolecular pi-stacking allows its efficient and soft immobilization at the surface of a Multi-Walled Carbon Nanotube (MWCNT) electrode. This MWCNT-supported galactose oxidase model exhibits a 4 H(+)/4 e(-) electrocatalytic activity towards oxygen reduction at a redox potential of 0.60 V vs. RHE at pH 5.

  9. Synthesis of 1H-Indazoles from Imidates and Nitrosobenzenes via Synergistic Rhodium/Copper Catalysis.

    Science.gov (United States)

    Wang, Qiang; Li, Xingwei

    2016-05-06

    Nitrosobenzenes have been used as a convenient aminating reagent for the efficient synthesis of 1H-indazoles via rhodium and copper catalyzed C-H activation and C-N/N-N coupling. The reaction occurred under redox-neutral conditions with high efficiency and functional group tolerance. Moreover, a rhodacyclic imidate complex has been identified as a key intermediate.

  10. Copper nitride nanocubes: size-controlled synthesis and application as cathode catalyst in alkaline fuel cells.

    Science.gov (United States)

    Wu, Haibin; Chen, Wei

    2011-10-05

    Copper nitride nanocubes are synthesized in a facile one-phase process. The crystal size could be tuned easily by using different primary amines as capping agents. Such Pt-free nanocrystals exhibit electrocatalytic activity toward oxygen reduction and appear to be promising cathodic electrocatalysts in alkaline fuel cells.

  11. Copper(II) mediated facile and ultra fast peptide synthesis in methanol.

    Science.gov (United States)

    Mali, Sachitanand M; Jadhav, Sandip V; Gopi, Hosahudya N

    2012-07-18

    A novel, ultrafast, mild and scalable amide bond formation strategy in methanol using simple thioacids and amines is described. The mechanism suggests that the coupling reactions are initially mediated by CuSO(4)·5H(2)O and subsequently catalyzed by in situ generated copper sulfide. The pure peptides were isolated in satisfactory yields in less than 5 minutes.

  12. Copper and copper proteins in Parkinson's disease.

    Science.gov (United States)

    Montes, Sergio; Rivera-Mancia, Susana; Diaz-Ruiz, Araceli; Tristan-Lopez, Luis; Rios, Camilo

    2014-01-01

    Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology.

  13. Identification of a novel enzymatic activity from lactic acid bacteria able to degrade biogenic amines in wine.

    Science.gov (United States)

    Callejón, S; Sendra, R; Ferrer, S; Pardo, I

    2014-01-01

    The main objectives of this study were the search for enzymatic activities responsible for biogenic amine (BA) degradation in lactic acid bacteria (LAB) strains isolated from wine, their identification, and the evaluation of their applicability for reducing BAs in wine. Fifty-three percent of the 76 LAB cell extracts showed activity against a mixture of histamine, tyramine, and putrescine when analyzed in-gel. The quantification of the degrading ability for each individual amine was tested in a synthetic medium and wine. Most of the bacteria analyzed were able to degrade the three amines in both conditions. The highest percentages of degradation in wine were those of putrescine: up to 41% diminution in 1 week. Enzymes responsible for amine degradation were isolated and purified from Lactobacillus plantarum J16 and Pediococcus acidilactici CECT 5930 strains and were identified as multicopper oxidases. This is the first report of an efficient BA reduction in wine by LAB. Furthermore, the identity of the enzymes involved has been revealed.

  14. Copper induces the expression of cholesterogenic genes in human macrophages.

    Science.gov (United States)

    Svensson, Per Arne; Englund, Mikael C O; Markström, Emilia; Ohlsson, Bertil G; Jernås, Margareta; Billig, Håkan; Torgerson, Jarl S; Wiklund, Olov; Carlsson, Lena M S; Carlsson, Björn

    2003-07-01

    Accumulation of lipids and cholesterol by macrophages and subsequent transformation into foam cells are key features in development of atherosclerosis. Serum copper concentrations have been shown to be associated with cardiovascular disease. However, the mechanism behind the proatherogenic effect of copper is not clear. We used DNA microarrays to define the changes in gene expression profile in response to copper exposure of human macrophages. Expression monitoring by DNA microarray revealed 91 genes that were regulated. Copper increased the expression of seven cholesterogenic genes (3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) synthase, IPP isomerase, squalene synthase, squalene epoxidase, methyl sterol oxidase, H105e3 mRNA and sterol-C5-desaturase) and low-density lipoprotein receptor (LDL-R), and decreased the expression of CD36 and lipid binding proteins. The expression of LDL-R and HMG CoA reductase was also investigated using real time PCR. The expression of both of these genes was increased after copper treatment of macrophages (Pmechanism for the association between copper and atherosclerosis. The effect of copper on cholesterogenic genes may also have implications for liver steatosis in early stages of Wilson's disease.

  15. The ccoNOQP gene cluster codes for a cb-type cytochrome oxidase that functions in aerobic respiration of Rhodobacter capsulatus.

    Science.gov (United States)

    Thöny-Meyer, L; Beck, C; Preisig, O; Hennecke, H

    1994-11-01

    The genes for a new type of a haem-copper cytochrome oxidase were cloned from Rhodobacter capsulatus strain 37b4, using the Bradyrhizobium japonicum fixNOQP gene region as a hybridizing probe. Four genes, probably organized in an operon (ccoNOQP), were identified; their products share extensive amino acid sequence similarity with the FixN, O, Q and P proteins that have recently been shown to be the subunits of a cb-type oxidase. CcoN is a b-type cytochrome, CcoO and CcoP are membrane-bound mono- and dihaem c-type cytochromes and CcoQ is a small membrane protein of unknown function. Genes for a similar oxidase are also present in other non-rhizobial bacterial species such as Azotobacter vinelandii, Agrobacterium tumefaciens and Pseudomonas aeruginosa, as revealed by polymerase chain reaction analysis. A ccoN mutant was constructed whose phenotype, in combination with the structural information on the gene products, provides evidence that the CcoNOQP oxidase is a cytochrome c oxidase of the cb type, which supports aerobic respiration in R. capsulatus and which is probably identical to the cbb3-type oxidase that was recently purified from a different strain of the same species. Mutant analysis also showed that this oxidase has no influence on photosynthetic growth and nitrogen-fixation activity.

  16. Vanillyl-alcohol oxidase, a tasteful biocatalyst

    NARCIS (Netherlands)

    Heuvel, Robert H.H. van den; Fraaije, Marco W.; Mattevi, Andrea; Laane, Colja; Berkel, Willem J.H. van

    2001-01-01

    The covalent flavoenzyme vanillyl-alcohol oxidase (VAO) is a versatile biocatalyst. It converts a wide range of phenolic compounds by catalysing oxidation, deamination, demethylation, dehydrogenation and hydroxylation reactions. The production of natural vanillin, 4-hydroxybenzaldehyde, coniferyl al

  17. Multilayered Thin Films from Poly(amido amine)s and DNA

    NARCIS (Netherlands)

    Hujaya, S.D.; Engbersen, J.F.J.; Paulusse, J.M.J.

    2015-01-01

    Dip-coated multilayered thin films of poly(amido amine)s (PAAs) and DNA have been developed to provide surfaces with cell-transfecting capabilities. Three types of PAAs, differing in side chain functional groups, were synthesized and characterized for their properties in forming multilayered structu

  18. Accurate determination of aldehydes in amine catalysts or amines by 2,4-dinitrophenylhydrazine derivatization.

    Science.gov (United States)

    Barman, Bhajendra N

    2014-01-31

    Carbonyl compounds, specifically aldehydes, present in amine catalysts or amines are determined by reversed-phase liquid chromatography using ultraviolet detection of their corresponding 2,4-dinitrophenylhydrazones. The primary focus has been to establish optimum conditions for determining aldehydes accurately because these add exposure concerns when the amine catalysts are used to manufacture polyurethane products. Concentrations of aldehydes determined by this method are found to vary with the pH of the aqueous amine solution and the derivatization time, the latter being problematic when the derivatization reaction proceeds slowly and not to completion in neutral and basic media. Accurate determination of aldehydes in amines through derivatization can be carried out at an effective solution pH of about 2 and with derivatization time of 20min. Hydrochloric acid has been used for neutralization of an amine. For complete derivatization, it is essential to protonate all nitrogen atoms in the amine. An approach for the determination of an adequate amount of acid needed for complete derivatization has been described. Several 0.2M buffer solutions varying in pH from 4 to 8 have also been used to make amine solutions for carrying out derivatization of aldehydes. These solutions have effective pHs of 10 or higher and provide much lower aldehyde concentrations compared to their true values. Mechanisms for the formation of 2,4-dinitrophenylhydrazones in both acidic and basic media are discussed.

  19. Reductive Amination of Aldehydes and Ketones with Primary Amines by Using Lithium Amidoborane as Reducing Reagent

    Institute of Scientific and Technical Information of China (English)

    徐维亮; 郑学丽; 吴国涛; 陈萍

    2012-01-01

    A variety of secondary amines were obtained in high isolated yields in the reductive amination of aldehydes and ketones by using lithium amidoborane as reducing agent. Compared to ammonia borane, lithium amidoborane has higher reducibility, and thus, exhibits faster reaction rate.

  20. Galactose oxidase nanoaggregates: Preparation and characterization

    OpenAIRE

    Mamta Sharma; Minakshi Sharma

    2016-01-01

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

  1. CCN activity of aliphatic amine secondary aerosol

    Directory of Open Access Journals (Sweden)

    X. Tang

    2014-01-01

    Full Text Available Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical. The particle composition can contain both secondary organic aerosol (SOA and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN activity. SOA formed from trimethylamine (TMA and butylamine (BA reactions with hydroxyl radical (OH is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25. Secondary aerosol formed from the tertiary aliphatic amine (TMA with N2O5 (source of nitrate radical, NO3, contains less volatile compounds than the primary aliphatic amine (BA aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR ideal mixing rules. Higher CCN activity (κ > 0.3 was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2, as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3. Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 < κ < 0.7. This work indicates that

  2. BIOGENIC AMINES CONTENT IN DIFFERENT WINE SAMPLES

    Directory of Open Access Journals (Sweden)

    Attila Kántor

    2015-02-01

    Full Text Available Twenty-five samples of different Slovak wines before and after filtration were analysed in order to determine the content of eight biogenic amines (tryptamine, phenylalanine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine. The method involves extraction of biogenic amines from wine samples with used dansyl chloride. Ultra-high performance liquid chromatography (UHPLC was used for determination of biogenic amines equipped with a Rapid Resolution High Definition (RRHD, DAD detectors and Extend-C18 LC column (50 mm x 3.0 mm ID, 1.8 μm particle size. In this study the highest level of biogenic amine in all wine samples represent tryptamine (TRM with the highest content 170.9±5.3 mg/L in Pinot Blanc wine. Phenylalanine (PHE cadaverine (CAD, histamine (HIS and spermidine (SPD were not detected in all wines; mainly SPD was not detected in 16 wines, HIS not detected in 14 wines, PHE and CAD not detected in 2 wines. Tyramine (TYR, spermine (SPN and putrescine (PUT were detected in all wines, but PUT and SPN in very low concentration. The worst wine samples with high biogenic amine content were Saint Laurent (BF, Pinot Blanc (S and Pinot Noir (AF.

  3. Biogenic amines in raw and processed seafood

    Directory of Open Access Journals (Sweden)

    Pierina eVisciano

    2012-06-01

    Full Text Available The presence of biogenic amines in raw and processed seafood, associated with either time/temperature conditions or food technologies is discussed in the present paper from a safety and prevention point of view. In particular, storage temperature, handling practices, presence of microbial populations with decarboxylase activity and availability of free amino acids are considered the most important factors affecting the production of biogenic amines in raw seafood. On the other hand, some food technological treatments such as salting, ripening, fermentation or marination can increase the levels of biogenic amines in processed seafood. The consumption of high amount of biogenic amines, above all histamine, can result in food borne poisoning which is a worldwide problem. The European Regulation established as maximum limits for histamine, in fishery products from fish species associated with high histidine amounts, values ranging from 100 to 200 mg/kg, while for products which have undergone enzyme maturation treatment in brine, the aforementioned limits rise to 200 and 400 mg/kg. Preventive measures and emerging methods aiming at controlling the production of biogenic amines are also reported for potential application in seafood industries.

  4. Improving Glyphosate Oxidation Activity of Glycine Oxidase from Bacillus cereus by Directed Evolution

    Science.gov (United States)

    Zhan, Tao; Zhang, Kai; Chen, Yangyan; Lin, Yongjun; Wu, Gaobing; Zhang, Lili; Yao, Pei; Shao, Zongze; Liu, Ziduo

    2013-01-01

    Glyphosate, a broad spectrum herbicide widely used in agriculture all over the world, inhibits 5-enolpyruvylshikimate-3-phosphate synthase in the shikimate pathway, and glycine oxidase (GO) has been reported to be able to catalyze the oxidative deamination of various amines and cleave the C-N bond in glyphosate. Here, in an effort to improve the catalytic activity of the glycine oxidase that was cloned from a glyphosate-degrading marine strain of Bacillus cereus (BceGO), we used a bacteriophage T7 lysis-based method for high-throughput screening of oxidase activity and engineered the gene encoding BceGO by directed evolution. Six mutants exhibiting enhanced activity toward glyphosate were screened from two rounds of error-prone PCR combined with site directed mutagenesis, and the beneficial mutations of the six evolved variants were recombined by DNA shuffling. Four recombinants were generated and, when compared with the wild-type BceGO, the most active mutant B3S1 showed the highest activity, exhibiting a 160-fold increase in substrate affinity, a 326-fold enhancement in catalytic efficiency against glyphosate, with little difference between their pH and temperature stabilities. The role of these mutations was explored through structure modeling and molecular docking, revealing that the Arg51 mutation is near the active site and could be an important residue contributing to the stabilization of glyphosate binding, while the role of the remaining mutations is unclear. These results provide insight into the application of directed evolution in optimizing glycine oxidase function and have laid a foundation for the development of glyphosate-tolerant crops. PMID:24223901

  5. Asymmetric Aminalization via Cation-Binding Catalysis

    DEFF Research Database (Denmark)

    Park, Sang Yeon; Liu, Yidong; Oh, Joong Suk

    2017-01-01

    Asymmetric cation-binding catalysis, in principle, can generate "chiral" anionic nucleophiles, where the counter cations are coordinated within chiral environments. Nitrogen-nucleophiles are intrinsically basic, therefore, its use as nucleophiles is often challenging and limiting the scope...... of the reaction. Particularly, a formation of configurationally labile aminal centers with alkyl substituents has been a formidable challenge due to the enamine/imine equilibrium of electrophilic substrates. Herein, we report enantioselective nucleophilic addition reactions of potassium phthalimides to Boc......-protected alkyl- and aryl-substituted α-amido sulfones. In-situ generated imines smoothly reacted with the nitrogen nucleophiles to corresponding aminals with good to excellent enantioselectivitiy under mild reaction conditions. In addition, transformation of aminal products gave biologically relevant...

  6. Amine permeation sources characterized with acid neutralization and sensitivities of an amine mass spectrometer

    Science.gov (United States)

    Freshour, N. A.; Carlson, K. K.; Melka, Y. A.; Hinz, S.; Panta, B.; Hanson, D. R.

    2014-10-01

    An acid titration method for quantifying amine permeation rates was used to calibrate an Ambient pressure Proton transfer Mass Spectrometer (AmPMS) that monitors ambient amine compounds. The method involves capturing amines entrained in a N2 flow by bubbling it through an acidified solution (~10-5 M HCl), and the amines are quantified via changes in solution pH with time. Home-made permeation tubes had permeation rates (typically tens of pmol s-1) that depended on the type of amine and tubing and on temperature. Calibrations of AmPMS yielded sensitivities for ammonia, methylamine, dimethylamine, and trimethylamine that are close to the sensitivity assuming a gas-kinetic, ion-molecule rate coefficient. The permeation tubes were also designed to deliver a reproducible amount of amine to a flow reactor where nucleation with sulfuric acid was studied. The high proton affinity compound dimethyl sulfoxide (DMSO), linked to oceanic environments, was also studied and AmPMS is highly sensitive to it. AmPMS was deployed recently in two field campaigns and, using these sensitivities, mixing ratios for ammonia and the alkyl amines are derived from the signals. Correlations between these species and with particle formation events are discussed.

  7. Interaction between hypocrellin and aliphatic amines

    Institute of Scientific and Technical Information of China (English)

    张曼华; 陈申; 夏万林; 蒋丽金; 陈德文

    1996-01-01

    The interaction of hypocrellin, including hypocrellin A (HA) and hypocrellin B (HB), with aliphatic amines in deaerated solutions has been studied by ESR and nanosecond transient absorption spectra. In polar solvents, the acid-base interaction between hypocrellin and amines was observed without irradiation. The signals of semiquinone radical anions of hypocrellm and the spin-trapping adduct of α-phenyl-N-tertbutyl-ratrone (PNB) with the aminoalkyl radicals have been detected in photoinduced ESR studies. The transient absorption of excited triplet state of HA and semiquinone radical anion of HA have been observed in laser flash photolysis studies.

  8. Conductive film by spray pyrolysis of self-reducing copper–silver amine complex solution

    Energy Technology Data Exchange (ETDEWEB)

    Suren, Sira; Limkitnuwat, Walailuk; Benjapongvimon, Phenfar; Kheawhom, Soorathep, E-mail: soorathep.k@chula.ac.th

    2016-05-31

    In this work, a facile method was demonstrated to prepare conductive film deposited on glass and polyimide (PI) substrates using spray pyrolysis of a copper–silver complex solution in nitrogen atmosphere. The copper–silver amine complex solution was prepared by mixing together the copper(II) acetate monohydrate, silver oxide, ammonia solution and di-ethanolamine. Four-point probe analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were employed to investigate the properties of the conductive film obtained. The effects of various parameters including spray pyrolysis temperature, molar ratio of copper to silver, type of substrate and annealing time were investigated. The volume resistivity of the film was decreased by using either higher spraying temperature or longer annealing time. In addition, the volume resistivity was also decreased by adding silver. At spray pyrolysis temperature 200 °C and annealing time 25 min. The conductive film with volume resistivity of 19.0 μΩ cm, which is 11 times higher than the resistivity of bulk copper, could be fabricated using molar ratio of copper to silver 0.8:0.2 on glass substrates. Copper oxide was not observed on the film deposited on the glass substrates. In contrast, the film deposited on the PI substrates contained copper oxide and exhibited resistivity 5 times higher than that deposited on the glass substrates. - Highlights: • Conductive films were made by spray pyrolysis of a copper–silver complex solution. • The volume resistivity of the film was decreased by using higher spraying temperature. • The volume resistivity of the film was decreased by using longer annealing time. • The volume resistivity of the film was decreased by adding silver. • The films fabricated on polyimide substrates exhibited higher volume resistivity.

  9. Enantioselective catalytic syntheses of alpha-branched chiral amines

    DEFF Research Database (Denmark)

    Brase, S.; Baumann, T.; Dahmen, S.

    2007-01-01

    Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials.......Chiral amines play a pivotal role in fine chemical and natural product syntheses and the design of novel materials....

  10. Photochemistry and Redox Chemistry of an Unsymmetrical Bimetallic Copper(I) Complex.

    Science.gov (United States)

    Back, Oliver; Leppin, Jana; Förster, Christoph; Heinze, Katja

    2016-10-03

    The bimetallic copper(I) complex Cu2L2 (cis-1) is formed with high diasteroselectivity from [Cu(NCCH3)4][BF4] and HL (4-tert-butyl phenyl(pyrrolato-2-yl-methylene)amine) in a kinetically controlled reaction. cis-1 features a rather short Cu···Cu distance of 2.4756(6) Å and is weakly emissive at room temperature in solution. Oxidatively triggered disproportionation of cis-1 yields elemental copper and the mononuclear copper(II) complex CuL2 (trans-2). One-electron reduction of trans-2 gives cuprate [2](-) with a bent bis(pyrrolato) coordinated copper(I) entity. The imine donor atoms of [2](-) can insert an additional copper(I) ion giving exclusively the bimetallic complex cis-1 closing the oxidation-elimination-reduction-insertion cycle.

  11. Identification and characterization of a novel Colletotrichum graminicola raffinose oxidase in the AA5 family.

    Science.gov (United States)

    Andberg, Martina; Mollerup, Filip; Parikka, Kirsti; Koutaniemi, Sanna; Boer, Harry; Juvonen, Minna; Master, Emma; Tenkanen, Maija; Kruus, Kristiina

    2017-08-04

    We describe here the identification and characterization of a copper radical oxidase from Auxiliary Activities Family 5 (AA5_2) that was distinguished by showing preferential activity towards raffinose. Despite the biotechnological potential of carbohydrate oxidases from family AA5, very few members have been characterized. The gene encoding raffinose oxidase activity from Colletotrichum graminicola, (Cg RaOx; EC 1.1.3.-) was identified utilizing a bioinformatics approach based on the known modular structure of a characterized AA5_2 galactose oxidase. Cg RaOx was expressed in Pichia pastoris and the purified enzyme displayed the highest activity on the trisaccharide raffinose, whereas the activity on the disaccharide melibiose was three times lower and more than ten times lower activity was detected on D-galactose at 300 mM substrate concentration. Thus, the substrate preference of Cg RaOx distinguished clearly from the known galactose oxidases. The site of oxidation for raffinose was studied by (1)H NMR and mass spectrometry, and confirmed that the hydroxyl group at the C6 position was oxidized to an aldehyde, and that in addition uronic acid was produced as a side product. A new ESI-MS method for the identification of C-6 oxidized products was developed and the formation mechanism of the uronic acid studied. Cg RaOx presented a novel activity pattern in the AA5 family.Importance Currently there are only a few characterized members of the CAZy AA5 protein family. These enzymes are interesting from an application point of view because of their ability to utilize the cheap and abundant oxidant O2 without the requirement ofcomplex cofactors such as FAD or NAD(P). Here we present the identification and characterization of a novel AA5 member from Colletotrichum graminicola As discussed in the paper, the bioinformatics approach using the modular structure of galactose oxidase was successful in finding a C6-OH carbohydrate oxidase having substrate preference for the

  12. The biochemical mechanisms of the plant activation of promutagenic aromatic amines

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, E.D.; Verdier, M.M.; Plewa, M.J. (Univ. of Illinois, Urbana (USA))

    1990-01-01

    Using specific monooxygenase and oxidase inhibitors in a plant cell/microbe coincubation assay, the biochemical mechanisms of the plant activation of two aromatic amines were compared. The biological endpoints included mutation induction, inhibition of mutagenicity, viability of the plant cells (activating system), and viability of the microbial cells. The activation of m-phenylenediamine by TX1 cells was mediated by enzyme systems that were inhibited by diethyldithiocarbamate, potassium cyanide, methimazole, (+)-catechin or acetaminophen. The inhibition by metyrapone was attended by toxicity in the plant cells. These data implicate a TX1 cell peroxidase and a FAD-dependent monoxygenase in the plant activation of m-phenylenediamine. The TX1 cell activation of 2-aminofluorene was inhibited by diethyldithiocarbamate, 7,8-benzoflavone, acetaminophen or (+)-catechin.

  13. Tertiary amines nucleophilicity in quaternization reaction with benzyl chloride

    Directory of Open Access Journals (Sweden)

    Ksenia S. Yutilova

    2016-03-01

    Full Text Available Quaternization reaction of tertiary amines with benzyl chloride was investigated. Reaction orders with respect to the reactants were determined. Kinetic scheme of quaternization reaction was found to be corresponding to reversible process. An influence of amines basicity and steric factor of alkyl substituent bound to the nitrogen atom on tertiary amines reactivity as nucleophiles was studied. It was shown that the rate constants of direct reaction step may serve as a measure of nucleophilicity of amines.

  14. MEDNIK syndrome: a novel defect of copper metabolism treatable by zinc acetate therapy.

    Science.gov (United States)

    Martinelli, Diego; Travaglini, Lorena; Drouin, Christian A; Ceballos-Picot, Irene; Rizza, Teresa; Bertini, Enrico; Carrozzo, Rosalba; Petrini, Stefania; de Lonlay, Pascale; El Hachem, Maya; Hubert, Laurence; Montpetit, Alexandre; Torre, Giuliano; Dionisi-Vici, Carlo

    2013-03-01

    MEDNIK syndrome-acronym for mental retardation, enteropathy, deafness, neuropathy, ichthyosis, keratodermia-is caused by AP1S1 gene mutations, encoding σ1A, the small subunit of the adaptor protein 1 complex, which plays a crucial role in clathrin coat assembly and mediates trafficking between trans-Golgi network, endosomes and the plasma membrane. MEDNIK syndrome was first reported in a few French-Canadian families sharing common ancestors, presenting a complex neurocutaneous phenotype, but its pathogenesis is not completely understood. A Sephardic-Jewish patient, carrying a new AP1S1 homozygous mutation, showed severe perturbations of copper metabolism with hypocupremia, hypoceruloplasminemia and liver copper accumulation, along with intrahepatic cholestasis. Zinc acetate treatment strikingly improved clinical conditions, as well as liver copper and bile-acid overload. We evaluated copper-related metabolites and liver function retrospectively in the original French-Canadian patient series. Intracellular copper metabolism and subcellular localization and function of copper pump ATP7A were investigated in patient fibroblasts. Copper metabolism perturbation and hepatopathy were confirmed in all patients. Studies in mutant fibroblasts showed abnormal copper incorporation and retention, reduced expression of copper-dependent enzymes cytochrome-c-oxidase and Cu/Zn superoxide dismutase, and aberrant intracellular trafficking of Menkes protein ATP7A, which normalized after rescue experiments expressing wild-type AP1S1 gene. We solved the pathogenetic mechanism of MEDNIK syndrome, demonstrating that AP1S1 regulates intracellular copper machinery mediated by copper-pump proteins. This multisystem disease is characterized by a unique picture, combining clinical and biochemical signs of both Menkes and Wilson's diseases, in which liver copper overload is treatable by zinc acetate therapy, and can now be listed as a copper metabolism defect in humans. Our results may also

  15. Incorporation of copper ions into crystals of T2 copper-depleted laccase from Botrytis aclada

    Energy Technology Data Exchange (ETDEWEB)

    Osipov, E. M., E-mail: e.m.osipov@gmail.com [A. N. Bach Institute of Biochemistry, Leninsky pr. 33, Moscow 119071 (Russian Federation); Polyakov, K. M. [A. N. Bach Institute of Biochemistry, Leninsky pr. 33, Moscow 119071 (Russian Federation); Engelhardt Institute of Molecular Biology, Vavilova str. 32, Moscow 119991 (Russian Federation); Tikhonova, T. V. [A. N. Bach Institute of Biochemistry, Leninsky pr. 33, Moscow 119071 (Russian Federation); Kittl, R. [BOKU – University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Wien (Austria); Dorovatovskii, P.V. [RSC ‘Kurchatov Institute’, Acad. Kurchatov sq. 1, Moscow 123182 (Russian Federation); Shleev, S. V.; Popov, V. O. [A. N. Bach Institute of Biochemistry, Leninsky pr. 33, Moscow 119071 (Russian Federation); RSC ‘Kurchatov Institute’, Acad. Kurchatov sq. 1, Moscow 123182 (Russian Federation); Ludwig, R. [BOKU – University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Wien (Austria)

    2015-11-18

    The restoration of the native form of laccase from B. aclada from the type 2 copper-depleted form of the enzyme was investigated. Copper ions were found to be incorporated into the active site after soaking the depleted enzyme in a Cu{sup +}-containing solution. Laccases belong to the class of multicopper oxidases catalyzing the oxidation of phenols accompanied by the reduction of molecular oxygen to water without the formation of hydrogen peroxide. The activity of laccases depends on the number of Cu atoms per enzyme molecule. The structure of type 2 copper-depleted laccase from Botrytis aclada has been solved previously. With the aim of obtaining the structure of the native form of the enzyme, crystals of the depleted laccase were soaked in Cu{sup +}- and Cu{sup 2+}-containing solutions. Copper ions were found to be incorporated into the active site only when Cu{sup +} was used. A comparative analysis of the native and depleted forms of the enzymes was performed.

  16. Oxidant-free conversion of primary amines to nitriles.

    Science.gov (United States)

    Tseng, Kuei-Nin T; Rizzi, Andrew M; Szymczak, Nathaniel K

    2013-11-06

    An amide-derived NNN-Ru(II) hydride complex catalyzes oxidant-free, acceptorless, and chemoselective dehydrogenation of primary and secondary amines to the corresponding nitriles and imines with liberation of dihydrogen. The catalyst system tolerates oxidizable functionality and is selective for the dehydrogenation of primary amines (-CH2NH2) in the presence of amines without α-CH hydrogens.

  17. 40 CFR 721.6140 - Dialkyldithiophosphoric acid, aliphatic amine salt.

    Science.gov (United States)

    2010-07-01

    ..., aliphatic amine salt. 721.6140 Section 721.6140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.6140 Dialkyldithiophosphoric acid, aliphatic amine salt. (a) Chemical... as a dialkyldithiophosphoric acid, aliphatic amine salt (P-90-1839) is subject to reporting under...

  18. Evolution of exchangeable copper and relative exchangeable copper through the course of Wilson's disease in the Long Evans Cinnamon rat.

    Directory of Open Access Journals (Sweden)

    Françoise Schmitt

    Full Text Available BACKGROUND: Wilson's disease (WD is an inherited disorder of copper metabolism leading to liver failure and/or neurological impairment. Its diagnosis often remains difficult even with genetic testing. Relative exchangeable copper (REC has recently been described as a reliable serum diagnostic marker for WD. METHODOLOGY/PRINCIPAL FINDINGS: The aim of this study was to validate the use of REC in the Long Evans Cinnamon (LEC rat, an animal model for WD, and to study its relevance under different conditions in comparison with conventional markers. Two groups of LEC rats and one group of Long-Evans (LE rats were clinically and biologically monitored from 6 to 28 weeks of age. One group of LEC rats was given copper-free food. The other groups had normal food. Blood samples were collected each month and different serum markers for WD (namely ceruloplasmin oxidase activity, exchangeable copper (CuEXC, total serum copper and REC and acute liver failure (serum transaminases and bilirubinemia were tested. Every LEC rat under normal food developed acute liver failure (ALF, with 40% global mortality. Serum transaminases and bilirubinemia along with total serum copper and exchangeable copper levels increased with the onset of acute liver failure. A correlation was observed between CuEXC values and the severity of ALF. Cut-off values were different between young and adult rats and evolved because of age and/or liver failure. Only REC, with values >19%, was able to discriminate LEC groups from the LE control group at every time point in the study. REC sensitivity and specificity reached 100% in adults rats. CONCLUSIONS/SIGNIFICANCE: REC appears to be independent of demographic or clinical data in LEC rats. It is a very simple and reliable blood test for the diagnosis of copper toxicosis owing to a lack of ATP7B function. CuEXC can be used as an accurate biomarker of copper overload.

  19. Fate and biodegradability of sulfonated aromatic amines

    NARCIS (Netherlands)

    Tan, N.C.G.; Leeuwen, van A.; Voorthuizen, van E.M.; Slenders, P.; Prenafeta, F.X.; Temmink, H.; Lettinga, G.; Field, J.A.

    2005-01-01

    Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only

  20. New adducts of Lapachol with primary amines

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Mirelly D.F.; Litivack-Junior, Jose T.; Antunes, Roberto V.; Silva, Tania M.S.; Camara, Celso A., E-mail: ccelso@dq.ufrpe.b [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Dept. de Quimica

    2011-07-01

    New adducts of lapachol with neat primary aliphatic amines were obtained in a solvent-free reaction in good to reasonable yields (52 to 88%), at room temperature. The new compounds containing a phenazine moiety were obtained from suitable functionalized aminoalkyl compounds, including ethanolamine, 3-propanolamine, 2-methoxy-ethylamine, 3-methoxy-propylamine, n-butylamine and 2-phenetylamine. (author)

  1. PEMIKIRAN QASIM AMIN TENTANG EMANSIPASI WANITA

    Directory of Open Access Journals (Sweden)

    Eliana Siregar

    2017-02-01

    Full Text Available The aim of this research is to explore the idea belong to Qosim Amin "Tahrir al-Mar'ah" as the main theme  of Qasim Amin reformation is an idea that is based on the spirit of liberation and empowerment of women. This idea emerged as a reflection and manifestation of concern intellectualism against the reality of Egyptian woman, who had reached the threshold of tolerance limits area . By using library research method, this research used book, journal, and others as the data resouces. As the cosequency, content analysis was used to analyse the data. Qasim Amin stresses that Islam should be granted rights of women in proportion tha is the right in education and acquire  same right in tasting educational right between men and women, because Islaic value is full of fairness and required the responsibility to Allah. The resut of this research shows that Qosim Amin concern on vision and educational issues in his Idea. There was an awareness of Egytianson the important position of women on education, chance of women to wear veily the government’s attention on the revision of religions justice. These changes have in fired the Egypt women todays.

  2. Catalytic Amination of Alcohols, Aldehydes, and Ketones

    Science.gov (United States)

    Klyuev, M. V.; Khidekel', M. L.

    1980-01-01

    Data on the catalytic amination of alcohols and carbonyl compounds are examined, the catalysts for these processes are described, and the problems of their effectiveness, selectivity, and stability are discussed. The possible mechanisms of the reactions indicated are presented. The bibliography includes 266 references.

  3. Affective disorder: studies with amine precursors.

    Science.gov (United States)

    Dunner, D L; Fieve, R R

    1975-02-01

    The authors assessed the clinical antidepressant effects of L-tryptophan given alone and in combination with L-dopa in 12 patients with a diagnosis of primary affective disorder; Preliminary results did not demonstrate an antidepressant response when L-dopa was combined with L-tryptophan. Also, the results did not support the catecholamine or biogenic amine hypotheses of affective disorder.

  4. Fate and biodegradability of sulfonated aromatic amines

    NARCIS (Netherlands)

    Tan, N.C.G.; Leeuwen, van A.; Voorthuizen, van E.M.; Slenders, P.; Prenafeta, F.X.; Temmink, H.; Lettinga, G.; Field, J.A.

    2005-01-01

    Ten sulfonated aromatic amines were tested for their aerobic and anaerobic biodegradability and toxicity potential in a variety of environmental inocula. Of all the compounds tested, only two aminobenzenesulfonic acid (ABS) isomers, 2- and 4-ABS, were degraded. The observed degradation occurred only

  5. Glucose oxidase and graphene bionanocomposite bridged by ionic liquid unit for glucose biosensing application

    DEFF Research Database (Denmark)

    Jiang, Yuanyuan; Zhang, Qixian; Li, Fenghua

    2012-01-01

    Ionic liquid functionalized graphene (IL-graphene) composite was synthesized successfully through an epoxide ring-opening reaction between graphene oxide (GO) and amine-terminated ionic liquid (NH2-IL). The IL-graphene exhibited good electronic conductivity, stability and electrocatalytical...... activity towards the reduction of O2 and H2O2. Then negatively charged glucose oxidase (GOD) was immobilized onto the composite matrix simply by ionic exchange. The ionic liquid here could improve the dispersibility of graphene and provide a favorable conductive microenvironment for the immobilized GOD......, thus promote its direct electron transfer at the GC electrode. This novel IL-graphene–GOD bionanocomposite could act as a biosensor towards the detection of glucose with a linear response up to 16mM. In this report, the method for immobilizing GOD by ionic interaction is of universality and has...

  6. [Copper IUDs (author's transl)].

    Science.gov (United States)

    Thiery, M

    1983-10-01

    Following initial development of the Grafenberg ring in the 1920's, IUDs fell into disuse until the late 1950s, when plastic devices inserted using new technology began to gain worldwide acceptance. Further research indicated that copper had a significant antifertility effect which increased with increasing surface area, and several copper IUDs were developed and adapted, including the Copper T 200, the Copper T 220C, and the Copper T 380 A, probably the most effective yet. The Gravigard and Multiload are 2 other copper devices developed according to somewhat different principles. Copper devices are widely used not so much because of their great effectiveness as because of their suitability for nulliparous patients and their ease of insertion, which minimizes risk of uterine perforation. Records of 2584 women using Copper IUDs for 7190 women-years and 956 women using devices without copper for 6059 women-years suggest that the copper devices were associated with greater effectiveness and fewer removals for complications. Research suggests that the advantages of copper IUDs become more significant with increased duration of use. Contraindications to copper devices include allergy to copper and hepatolenticular degeneration. No carcinogenic or teratogenic effect of copper devices has been found, but further studies are needed to rule out other undesirable effects. Significant modifications of copper devices in recent years have been developed to increase their effectiveness, prolong their duration of usefulness, facilitate insertion and permit insertion during abortion or delivery. The upper limit of the surface area of copper associated with increased effectiveness appears to be between 200-300 sq mm, and at some point increases in copper exposure may provoke expulsion of the IUD. The duration of fertility inhibition of copper IUDs is usually estimated at 2-3 years, but recent research indicates that it may be 6-8 years, and some devices may retain copper surface

  7. Oms1 associates with cytochrome c oxidase assembly intermediates to stabilize newly synthesized Cox1.

    Science.gov (United States)

    Bareth, Bettina; Nikolov, Miroslav; Lorenzi, Isotta; Hildenbeutel, Markus; Mick, David U; Helbig, Christin; Urlaub, Henning; Ott, Martin; Rehling, Peter; Dennerlein, Sven

    2016-05-15

    The mitochondrial cytochrome c oxidase assembles in the inner membrane from subunits of dual genetic origin. The assembly process of the enzyme is initiated by membrane insertion of the mitochondria-encoded Cox1 subunit. During complex maturation, transient assembly intermediates, consisting of structural subunits and specialized chaperone-like assembly factors, are formed. In addition, cofactors such as heme and copper have to be inserted into the nascent complex. To regulate the assembly process, the availability of Cox1 is under control of a regulatory feedback cycle in which translation of COX1 mRNA is stalled when assembly intermediates of Cox1 accumulate through inactivation of the translational activator Mss51. Here we isolate a cytochrome c oxidase assembly intermediate in preparatory scale from coa1Δ mutant cells, using Mss51 as bait. We demonstrate that at this stage of assembly, the complex has not yet incorporated the heme a cofactors. Using quantitative mass spectrometry, we define the protein composition of the assembly intermediate and unexpectedly identify the putative methyltransferase Oms1 as a constituent. Our analyses show that Oms1 participates in cytochrome c oxidase assembly by stabilizing newly synthesized Cox1.

  8. Activity-stability relationships revisited in blue oxidases catalyzing electron transfer at extreme temperatures.

    Science.gov (United States)

    Roulling, Frédéric; Godin, Amandine; Cipolla, Alexandre; Collins, Tony; Miyazaki, Kentaro; Feller, Georges

    2016-09-01

    Cuproxidases are a subset of the blue multicopper oxidases that catalyze the oxidation of toxic Cu(I) ions into less harmful Cu(II) in the bacterial periplasm. Cuproxidases from psychrophilic, mesophilic, and thermophilic bacteria display the canonical features of temperature adaptation, such as increases in structural stability and apparent optimal temperature for activity with environmental temperature as well as increases in the binding affinity for catalytic and substrate copper ions. In contrast, the oxidative activities at 25 °C for both the psychrophilic and thermophilic enzymes are similar, suggesting that the nearly temperature-independent electron transfer rate does not require peculiar adjustments. Furthermore, the structural flexibilities of both the psychrophilic and thermophilic enzymes are also similar, indicating that the firm and precise bindings of the four catalytic copper ions are essential for the oxidase function. These results show that the requirements for enzymatic electron transfer, in the absence of the selective pressure of temperature on electron transfer rates, produce a specific adaptive pattern, which is distinct from that observed in enzymes possessing a well-defined active site and relying on conformational changes such as for the induced fit mechanism.

  9. Methylamine-Sensitive Amperometric Biosensor Based on (His6-Tagged Hansenula polymorpha Methylamine Oxidase Immobilized on the Gold Nanoparticles

    Directory of Open Access Journals (Sweden)

    Nataliya Ye. Stasyuk

    2014-01-01

    Full Text Available A novel methylamine-selective amperometric bienzyme biosensor based on recombinant primary amine oxidase isolated from the recombinant yeast strain Saccharomyces cerevisiae and commercial horseradish peroxidase is described. Two amine oxidase preparations were used: free enzyme (AMO and covalently immobilized on the surface of gold nanoparticles (AMO-nAu. Some bioanalytical parameters (sensitivity, selectivity, and storage stability of the developed biosensors were investigated. The sensitivity for both sensors is high: 1450 ± 113 and 700 ± 30 A−1·M−1·m−2 for AMO-nAu biosensor, respectively. The biosensors exhibit the linear range from 15 μM to 150 μM (AMO-nAu and from 15 μM to 60 μM (AMO. The developed biosensor demonstrated a good selectivity toward methylamine (MA (signal for dimethylamine and trimethylamine is less than 5% and for ethylamine 15% compared to MA output and reveals a satisfactory storage stability. The constructed amperometric biosensor was used for MA assay in real samples of fish products in comparison with chemical method. The values obtained with both approaches different methods demonstrated a high correlation.

  10. A subset of N-substituted phenothiazines inhibits NADPH oxidases.

    Science.gov (United States)

    Seredenina, Tamara; Chiriano, Gianpaolo; Filippova, Aleksandra; Nayernia, Zeynab; Mahiout, Zahia; Fioraso-Cartier, Laetitia; Plastre, Olivier; Scapozza, Leonardo; Krause, Karl-Heinz; Jaquet, Vincent

    2015-09-01

    NADPH oxidases (NOXs) constitute a family of enzymes generating reactive oxygen species (ROS) and are increasingly recognized as interesting drug targets. Here we investigated the effects of 10 phenothiazine compounds on NOX activity using an extensive panel of assays to measure production of ROS (Amplex red, WST-1, MCLA) and oxygen consumption. Striking differences between highly similar phenothiazines were observed. Two phenothiazines without N-substitution, including ML171, did not inhibit NOX enzymes, but showed assay interference. Introduction of an aliphatic amine chain on the N atom of the phenothiazine B ring (promazine) conferred inhibitory activity toward NOX2, NOX4, and NOX5 but not NOX1 and NOX3. Addition of an electron-attracting substituent in position 2 of the C ring extended the inhibitory activity to NOX1 and NOX3, with thioridazine being the most potent inhibitor. In contrast, the presence of a methylsulfoxide group at the same position (mesoridazine) entirely abolished NOX-inhibitory activity. A cell-free NOX2 assay suggested that inhibition by N-substituted phenothiazines was not due to competition with NADPH. A functional implication of NOX-inhibitory activity of thioridazine was demonstrated by its ability to block redox-dependent myofibroblast differentiation. Our results demonstrate that NOX-inhibitory activity is not a common feature of all antipsychotic phenothiazines and that substitution on the B-ring nitrogen is crucial for the activity, whereas that on the second position of the C ring modulates it. Our findings contribute to a better understanding of NOX pharmacology and might pave the path to discovery of more potent and selective NOX inhibitors.

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

    Science.gov (United States)

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

    2017-10-01

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

  12. Ligand-assisted, copper(II) acetate-accelerated azide-alkyne cycloaddition.

    Science.gov (United States)

    Michaels, Heather A; Zhu, Lei

    2011-10-04

    Polytriazole ligands such as the widely used tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine (TBTA), are shown to assist copper(II) acetate-mediated azide-alkyne cycloaddition (AAC) reactions that involve nonchelating azides. Tris(2-{4-[(dimethylamino)methyl]-1H-1,2,3-traizol-1-yl}ethyl)amine (DTEA) outperforms TBTA in a number of reactions. The satisfactory solubility of DTEA in a wide range of polar and nonpolar solvents, including water and toluene, renders it advantageous under copper(II) acetate-mediated conditions. The copper(II) acetate-mediated formation of the three triazolyl groups in a tris(triazolyl)-based ligand occurs sequentially with an inhibitory effect in the last step. The kinetic investigations of the ligand-assisted reactions reveal an interesting mechanistic dependence on the relative affinity of azide and alkyne to copper (II). In addition to expanding the scope of the copper(II) acetate-mediated AAC reactions to include nonchelating azides, this work offers evidence for the mechanistic synergy between the title reaction and the alkyne oxidative homocoupling reaction. The elucidation of the structural details of the polytriazole-ligand-bound reactive species in copper(I/II)-mediated AAC reactions, however, awaits further characterization of the metal coordination chemistry of polytriazole ligands. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Synthesis and characterization of heteroleptic copper and zinc complexes with saccharinate and aminoacids. Evaluation of SOD-like activity of the copper complexes.

    Science.gov (United States)

    Santi, Eduardo; Viera, Inés; Mombrú, Alvaro; Castiglioni, Jorge; Baran, Enrique J; Torre, María H

    2011-12-01

    Five new copper and zinc heteroleptic complexes with saccharin and aminoacids with general stoichiometry Na(2)[M(sac)(2)(aa)(2)].nH(2)O (M denotes Cu or Zn, sac the saccharinate ion, and aa the aminoacids) were synthesized and characterized by elemental and thermogravimetric analysis, conductimetric measurements and IR, Raman and UV-vis spectroscopies. In all the complexes, copper and zinc ions coordinated with the aminoacids through the terminal amine and carboxylate residues and with saccharin through the heterocyclic nitrogen atom. Besides, the superoxide dismutase-like activity of the heteroleptic copper complexes was evaluated and compared with the homoleptic copper amino acid complexes with the aim to observe the influence of the saccharin coordination.

  14. C-N Coupling of nitrogen nucleophiles with aryl and heteroaryl bromides using aminoarenethiolato-copper(I) (pre-)catalyst

    NARCIS (Netherlands)

    Sperotto, Elena; Klink, Gerard P.M. van; Vries, Johannes G. de; Koten, Gerard van

    2010-01-01

    The activity of a library of 2-aminoarenethiolato-copper(I) (CuSAr) (pre-)catalyst was explored in the arylation reaction of amines and N-containing heterocycles with aryl and heteroaryl bromides, respectively. These CuSAr pre-catalysts are thermally stable, are soluble in common organic solvents

  15. A mild method of amine-type adsorbents syntheses with emulsion graft polymerization of glycidyl methacrylate on polyethylene non-woven fabric by pre-irradiation

    Science.gov (United States)

    Ma, Hongjuan; Yao, Side; Li, Jingye; Cao, Changqing; Wang, Min

    2012-09-01

    A mild pre-irradiation method was used to graft glycidyl methacrylate (GMA) onto polyethylene (PE) non-woven fabric (NF). The polymer was irradiated by electron beam in air atmosphere at room temperature. The degree of grafting (Dg) was determined as a function of reaction time, absorbed dose, monomer concentration and temperature. After 30 kGy irradiation, with 5% GMA, surfactant Tween 20 (Tw-20) of 0.5% at 55 °C for 15 min, the trunk polymer was made grafted with a Dg of 150%. Selected PE-g-PGMA of different Dg was modified with aminated compounds such as ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA). The obtained amine-type adsorbents were prepared to remove copper and uranium ions from solution. It was shown that at least 90% of copper and 60% of uranium with the initial concentration from 3 to 1000 ppb can be removed from water.

  16. 21 CFR 866.2420 - Oxidase screening test for gonorrhea.

    Science.gov (United States)

    2010-04-01

    ... Section 866.2420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2420 Oxidase... ingredient that will react with cytochrome oxidase. When cytochrome oxidase is present, the swab turns a dark...

  17. Bilirubin Oxidase Activity of Bacillus subtilis CotA

    OpenAIRE

    Sakasegawa, S; Ishikawa, H.; Imamura, S.; Sakuraba, H.; Goda, S.; Ohshima, T.

    2006-01-01

    The spore coat protein CotA from Bacillus subtilis was previously identified as a laccase. We have now found that CotA also shows strong bilirubin oxidase activity and markedly higher affinity for bilirubin than conventional bilirubin oxidase. This is the first characterization of bilirubin oxidase activity in a bacterial protein.

  18. THERMOSTABILITY OF RESPIRATORY TERMINAL OXIDASES IN THE LIPID ENVIRONMENT

    NARCIS (Netherlands)

    Elferink, Marieke G.L.; Bosmal, Tjibbe; Lolkema, Juke S.; Gleiszner, Michael; Driessen, Arnold J.M.; Konings, Wil N.

    1995-01-01

    The effect of the lipid environment on the thermostability of three respiratory terminal oxidases was determined. Cytochrome-e oxidase from beef heart and Bacillus stearothermophilus were used as representative proteins from mesophilic and thermophilic origin, respectively. Quinol oxidase from the a

  19. Perspectives on the Role and Relevance of Copper in Cardiac Disease.

    Science.gov (United States)

    Medeiros, Denis M

    2017-03-01

    Cardiac hypertrophy as a result of dietary copper deficiency has been studied for 40 plus years and is the subject of this review. While connective tissue anomalies occur, a hallmark pathology is cardiac hypertrophy, increased mitochondrial biogenesis, with disruptive cristae, vacuolization of mitochondria, and deposition of lipid droplets. Electrocardiogram abnormalities have been demonstrated along with biochemical changes especially as it relates to the copper-containing enzyme cytochrome c oxidase. The master controller of mitochondrial biogenesis, PGC1-α expression and protein, along with other proteins and transcriptional factors that play a role are upregulated. Nitric oxide, vascular endothelial growth factor, and cytochrome c oxidase all may enhance the upregulation of mitochondrial biogenesis. Marginal copper intakes reveal similar pathologies in the absence of cardiac hypertrophy. Reversibility of the copper-deficient rat heart with a copper-replete diet has resulted in mixed results, depending on both the animal model used and temporal relationships. New information has revealed that copper supplementation may rescue cardiac hypertrophy induced by pressure overload.

  20. Occurrence and Biocatalytic Potential of Carbohydrate Oxidases.

    NARCIS (Netherlands)

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

    2006-01-01

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

  1. A colorimetric assay for cytokinin oxidase.

    Science.gov (United States)

    Libreros-Minotta, C A; Tipton, P A

    1995-11-01

    A simple and rapid colorimetric assay for cytokinin oxidase is described. The assay is based on the formation of a Schiff base between the enzymatic reaction product 3-methyl-2-butenal and p-aminophenol. The assay is effective in the submicromolar concentration range and can be used in crude plant extracts as well as in more highly purified preparations.

  2. Spectrophotometric Assay of Immobilized Glucose Oxidase

    Directory of Open Access Journals (Sweden)

    Nojan Noorbehesht

    2016-06-01

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

  3. Lysyl oxidase mediates hypoxic control of metastasis

    DEFF Research Database (Denmark)

    Erler, Janine Terra; Giaccia, Amato J

    2006-01-01

    Hypoxic cancer cells pose a great challenge to the oncologist because they are especially aggressive, metastatic, and resistant to therapy. Recently, we showed that elevation of the extracellular matrix protein lysyl oxidase (LOX) correlates with metastatic disease and is essential for hypoxia...

  4. CCN activity of aliphatic amine secondary aerosol

    Science.gov (United States)

    Tang, X.; Price, D.; Praske, E.; Vu, D.; Purvis-Roberts, K.; Silva, P. J.; Cocker, D. R., III; Asa-Awuku, A.

    2014-01-01

    Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical). The particle composition can contain both secondary organic aerosol (SOA) and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN) activity. SOA formed from trimethylamine (TMA) and butylamine (BA) reactions with hydroxyl radical (OH) is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25). Secondary aerosol formed from the tertiary aliphatic amine (TMA) with N2O5 (source of nitrate radical, NO3), contains less volatile compounds than the primary aliphatic amine (BA) aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR) ideal mixing rules. Higher CCN activity (κ > 0.3) was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2), as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3). Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss) settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 systems.

  5. Reaction of 5-amino-8-hydroxy-1,4 naphthoquinone with aliphatic and aromatic amines. Theoretical study of its tantomeric equilibria and reactivity; Reaccion de la 5-amino-8-hidroxi-1,4-naftoquinona con aminas alifaticas y aromaticas. Estudio teorico de su equilibrio tantomerico y reactividad

    Energy Technology Data Exchange (ETDEWEB)

    Franceschini, F.C. [Departamento de Quimica Organica, Instituto de Quimica UFRGS Porto Alegre (Brazil); Sanchez Alonso, F.; Stefani, V. [Instituto de Quimica Organica General, CSIC, Madrid (Spain)

    1995-12-31

    The reaction of 5-amino-8-hydroxy-1,4-naphthoquinone (1) with aliphatic and aromatic amines have been studied, in absence or present of copper (II) salts, in order to prepare diamino hydroxy-1,4-naphthoquinones. Also a quantum mechanics calculation on 1 have been done for studying its tautomeric equilibria and rationalizing its behaviour in the reaction with amines. (Author) 32 refs.

  6. Regioselective synthesis of 1-alkyl- or 1-aryl-1H-indazoles via copper-catalyzed cyclizations of 2-haloarylcarbonylic compounds.

    Science.gov (United States)

    Viña, Dolores; del Olmo, Esther; López-Pérez, José L; San Feliciano, Arturo

    2007-02-01

    [reaction: see text] A general method for the one-step regioselective synthesis of 1-alkyl- or 1-aryl-1H-indazoles from ortho-halogenated alkanoylphenones, benzophenones, and arylcarboxylic acids, via copper-catalyzed amination, was developed by using 0.2% mol of CuO in the presence of K(2)CO(3). The reaction involves amination followed by intramolecular dehydration. Different functionalized alkyl aryl ketones, diaryl ketones, and benzoic acid derivatives were efficiently coupled with several hydrazines. Ligands commonly employed as catalysts for intermolecular amination were shown to be ineffective for this cyclization.

  7. CuI-nanoparticles-catalyzed one-pot synthesis of benzo[b]furans via three-component coupling of aldehydes, amines and alkyne

    Directory of Open Access Journals (Sweden)

    Javad Safaei-Ghomi

    2016-09-01

    Full Text Available A novel application of copper iodide nanoparticles as an efficient catalyst has been developed for the synthesis of 2,3-disubstituted benzo[b]furan derivatives via three-component coupling of aldehydes, secondary amines and alkyne. The method presented is green, effective, inexpensive and satisfactory to give the products in high yields and short reaction times by the use of novel nanoscale materials.

  8. Mitochondrial cytochrome c oxidase: mechanism of action and role in regulating oxidative phosphorylation.

    Science.gov (United States)

    Wilson, David F; Vinogradov, Sergei A

    2014-12-15

    Mitochondrial oxidative phosphorylation has a central role in eukaryotic metabolism, providing the energy (ATP) required for survival. Regulation of this important pathway is, however, still not understood, largely due to limitations in the ability to measure the essential metabolites, including oxygen (pO2, oxygen pressure), ADP, and AMP. In addition, neither the mechanism of oxygen reduction by mitochondrial cytochrome c oxidase nor how its rate is controlled is understood, although this enzyme determines the rate of oxygen consumption and thereby the rate of ATP synthesis. Cytochrome c oxidase is responsible for reduction of molecular oxygen to water using reducing equivalents donated by cytochrome c and for site 3 energy coupling in oxidative phosphorylation. A mechanism-based model of the cytochrome c oxidase reaction is presented in which transfer of reducing equivalents from the lower- to the higher-potential region of the coupling site occurs against an opposing energy barrier, Q. The steady-state rate equation is fitted to data for the dependence of mitochondrial respiratory rate on cytochrome c reduction, oxygen pressure (pO2), and [ATP]/[ADP][Pi] at pH 6.5 to 8.35 (where Pi is inorganic phosphate). The fit of the rate expression to the experimental data is very good for all experimental conditions. Levels of the intermediates in oxygen reduction in the oxidase reaction site have been calculated. An intermediate in the reaction, tentatively identified as peroxide, bridged between the iron and copper atoms of the reaction site has a central role in coupling mitochondrial respiration to the [ATP]/[ADP][Pi].

  9. SiO2-Cu2O:An efficient and recyclable heterogeneous catalyst for N-benzylation of primary and secondary amines

    Institute of Scientific and Technical Information of China (English)

    Manjulla Gupta; Satya Paul; Rajive Gupta

    2014-01-01

    A mild, effective, and selective procedure is reported for the mono N-benzylation and N,N- diben-zylation of primary amines as well as mono N-benzylation of secondary amines using sili-ca-supported copper(I) oxide in water. The silica-supported Cu2O was generated in situ by the reac-tion of Fehling solution and glucose at 100 °C onto activated silica. The catalyst was filtered, washed with water, and oven-dried, and was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and atomic absorption spectroscopy. The prepared Cu2O-SiO2 was found to be thermally stable up to 325 °C. The copper was uniformly distributed onto the surface of the silica, and the mean particle diameter was 7 nm. The catalyst served as a selective heterogenous catalyst for the N-benzylation of primary and secondary amines. The catalyst is recyclable and was used effectively upto fifth run without a significant loss of catalytic activity. Various reaction solvents including water, acetonitrile, and toluene were screened for N-benzylation of amines, and the success of the aqueous system highlights the low environmental impact of the procedure.

  10. Development of a general non-noble metal catalyst for the benign amination of alcohols with amines and ammonia.

    Science.gov (United States)

    Cui, Xinjiang; Dai, Xingchao; Deng, Youquan; Shi, Feng

    2013-03-11

    The N-alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N-alkyl amines. However, as a potentially clean and economic choice for N-alkyl amine synthesis, non-noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N-alkylation of ammonia or amines with alcohol or primary amines. N-alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N-heterocyclic compounds, and secondary amines could be N-alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one-pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation.

  11. A new phenol oxidase produced during melanogenesis and encystment stage in the nitrogen-fixing soil bacterium Azotobacter chroococcum.

    Science.gov (United States)

    Herter, Susanne; Schmidt, Marlen; Thompson, Mark L; Mikolasch, Annett; Schauer, Frieder

    2011-05-01

    Laccases are copper-containing phenol oxidases that are commonly found in many types of plant, insect, fungi and bacteria. Whilst phenol oxidases have been well characterized in fungal species, laccase-type enzymes originating from bacteria have been much less well defined. Bacteria belonging to the family Azotobacteraceae share many morphological characteristics with strains already known to exhibit polyphenol and phenol oxidase activity; and hence the aim of this work was to identify and characterize a novel laccase from the isolated strain Azotobacter chroococcum SBUG 1484 in an attempt to provide further understanding of the roles such enzymes play in physiological development. Laccase activity was clearly observed through oxidation of 2,6-dimethoxyphenol, other typical substrates including: methoxy-monophenols, ortho- and para-diphenols, 4-hydroxyindole, and the non-phenolic compound para-phenylenediamine. A. chroococcum SBUG 1484 showed production of a cell-associated phenol oxidase when grown under nitrogen-fixing conditions, and was also observed when cells enter the melanogenic and encystment stages of growth. Catechol which is structurally related to melanin compounds was also released from Azotobacter cells into the surrounding culture medium during nitrogen-fixing growth. From our results we propose that a membrane-bound laccase plays an important role in the formation of melanin, which was monitored to correlate with progression of A. chroococcum SBUG 1484 cells into the encystment stage of growth.

  12. Relation between the catalytic efficiency of the synthetic analogues of catechol oxidase with their electrochemical property in the free state and substrate-bound state.

    Science.gov (United States)

    Chakraborty, Prateeti; Adhikary, Jaydeep; Ghosh, Bipinbihari; Sanyal, Ria; Chattopadhyay, Shyamal Kumar; Bauzá, Antonio; Frontera, Antonio; Zangrando, Ennio; Das, Debasis

    2014-08-18

    A library of 15 dicopper complexes as synthetic analogues of catechol oxidase has been synthesized with the aim to determine the relationship between the electrochemical behavior of the dicopper(II) species in the absence as well as in the presence of 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the catalytic activity, kcat, in DMSO medium. The complexes have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis in some cases. Fifteen "end-off" compartmental ligands have been designed as 1 + 2 Schiff-base condensation product of 2,6-diformyl-4-R-phenol (R = Me, (t)Bu, and Cl) and five different amines, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, and N-(2-aminoethyl)piperidine. Interestingly, in case of the combination of 2,6-diformyl-4-methylphenol and N-(2-aminoethyl)morpholine/N-(3-aminopropyl)morpholine/N-(2-aminoethyl)piperidine 1 + 1 condensation becomes the reality and the ligands are denoted as L2(1-3). On reaction of copper(II) nitrate with L2(1-3) in situ complexes 3, 12, and 13 are formed having general formula Cu2(L2(1-3))2(NO3)2. The remaining 12 ligands obtained as 1 + 2 condensation products are denoted as L1(1-12), which produce complexes having general formula Cu2(L1(1-12))(NO3)2. Catecholase activity of all 15 complexes has been investigated in DMSO medium using 3,5-DTBC as model substrate. Treatment on the basis of Michaelis-Menten model has been applied for kinetic study, and thereby turnover number, kcat, values have been evaluated. Cyclic voltametric (CV) and differential pulse voltametric (DPV) studies of the complexes in the presence as well as in the absence of 3,5-DTBC have been thoroughly investigated in DMSO medium. From those studies it is evident that oxidation of 3,5-DTBC catalyzed by dicopper(II) complexes proceed via two steps: first, semibenzoquinone followed by benzoquinone with concomitant

  13. Sonophotocatalytic Degradation of Amines in Water

    Science.gov (United States)

    Verman, Mayank; Pankaj

    Hazardous effects of various amines, produced in the environment from the partial degradation of azo dyes and amino acids, adversely affect the quality of human life through water, soil and air pollution and therefore needed to be degraded. A number of such studies are already available in the literature, with or without the use of ultrasound, which have been summarized briefly. The sonochemical degradation of amines and in the combination with a photocatalyst, TiO2 has also been discussed. Similar such degradation studies for ethylamine (EA), aniline (A), diphenylamine (DPA) and naphthylamine (NA) in the presence of ultrasound, TiO2 and rare earths (REs); La, Pr, Nd, Sm and Gd, in aqueous solutions at 20 kHz and 250 W power have been carried out and reported, to examine the combinatorial efficacy of ultrasound in the presence of a photocatalyst and rare earth ions with reactive f-electrons.

  14. Amine chemistry. Update on impact on resin

    Energy Technology Data Exchange (ETDEWEB)

    Bachman, Gregory; Kellogg, Douglas [Siemens Industry, Inc., Rockford, IL (United States). Technology and Lab Services; Wilkes, Marty [Siemens Industry, Inc., Rockford, IL (United States). Water Technologies Div.

    2012-03-15

    Impurity removal in the steam cycle and the associated prevention of corrosion and/or fouling of system components are the goals of ion exchange resins. However, in many instances (such as a switch to amine chemistry or a change in product specifications), resins do not remove, and, in fact, contribute impurities to the steam cycle. This paper reviews recent data compiled to determine the direct and indirect effects of amines on ion exchange resins used in the power industry. Water chemistries have improved in recent years, in large part due to changes in chemistry and resins, but it is necessary to continue to develop products, processes and techniques to reduce impurities and improve overall water chemistry in power plant systems. (orig.)

  15. Organic chemistry. Strain-release amination.

    Science.gov (United States)

    Gianatassio, Ryan; Lopchuk, Justin M; Wang, Jie; Pan, Chung-Mao; Malins, Lara R; Prieto, Liher; Brandt, Thomas A; Collins, Michael R; Gallego, Gary M; Sach, Neal W; Spangler, Jillian E; Zhu, Huichin; Zhu, Jinjiang; Baran, Phil S

    2016-01-15

    To optimize drug candidates, modern medicinal chemists are increasingly turning to an unconventional structural motif: small, strained ring systems. However, the difficulty of introducing substituents such as bicyclo[1.1.1]pentanes, azetidines, or cyclobutanes often outweighs the challenge of synthesizing the parent scaffold itself. Thus, there is an urgent need for general methods to rapidly and directly append such groups onto core scaffolds. Here we report a general strategy to harness the embedded potential energy of effectively spring-loaded C-C and C-N bonds with the most oft-encountered nucleophiles in pharmaceutical chemistry, amines. Strain-release amination can diversify a range of substrates with a multitude of desirable bioisosteres at both the early and late stages of a synthesis. The technique has also been applied to peptide labeling and bioconjugation.

  16. Catalytic dehydrogenation of amine borane complexes

    Science.gov (United States)

    Mohajeri, Nahid (Inventor); Tabatabaie-Raissi, Ali (Inventor); Bokerman, Gary (Inventor)

    2009-01-01

    A method of generating hydrogen includes the steps of providing an amine borane (AB) complex, at least one hydrogen generation catalyst, and a solvent, and mixing these components Hydrogen is generated. The hydrogen produced is high purity hydrogen suitable for PEM fuel cells. A hydrolytic in-situ hydrogen generator includes a first compartment that contains an amine borane (AB) complex, a second container including at least one hydrogen generation catalyst, wherein the first or second compartment includes water or other hydroxyl group containing solvent. A connecting network permits mixing contents in the first compartment with contents in the second compartment, wherein high purity hydrogen is generated upon mixing. At least one flow controller is provided for controlling a flow rate of the catalyst or AB complex.

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

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Chen Xiaoyang; Li Hui; Guo Hai

    2003-01-01

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

  18. Amine reactivity with charged sulfuric acid clusters

    Science.gov (United States)

    Bzdek, B. R.; Ridge, D. P.; Johnston, M. V.

    2011-08-01

    The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge), both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia is also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4)(H2SO4)x]- and [(NH4)x(HSO4)x+1(H2SO4)3]-. Dimethylamine substitution for ammonia in [(NH4) x(HSO4) x+1(H2SO4)3]- clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 to bisulfate is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4) (H2SO4) x]- clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (>m/z 400), whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2-3 orders of magnitude slower than incorporation of dimethylamine either by substitution or addition. Therefore, in locations where amine levels are within a few orders of magnitude of ammonia levels, amine chemistry may compete favorably with ammonia chemistry.

  19. Whole cell biotransformation for reductive amination reactions

    OpenAIRE

    Klatte, Stephanie; Lorenz, Elisabeth; Wendisch, Volker F.

    2013-01-01

    Whole cell biotransformation systems with enzyme cascading increasingly find application in biocatalysis to complement or replace established chemical synthetic routes for production of, e.g., fine chemicals. Recently, we established an Escherichia coli whole cell biotransformation system for reductive amination by coupling a transaminase and an amino acid dehydrogenase with glucose catabolism for cofactor recycling. Transformation of 2-keto-3-methylvalerate to l-isoleucine by E. coli cells w...

  20. Rate phenomena in uranium extraction by amines

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, C. F.; McDowell, W. J.

    1979-01-01

    Kinetics studies and other rate measurements are reviewed in the amine extraction of uranium and of some other related and associated metal ions. Equilibration is relatively fast in the uranium sulfate systems most important to uranium hydrometallurgy. Significantly slow equilibration has been encountered in some other systems. Most of the recorded rate information, both qualitative and quantitative, has come from exploratory and process-development work, while some kinetics studies have been directed specifically toward elucidation of extraction mechanisms. 71 references.

  1. Electrophilic amination: the case of nitrenoids.

    Science.gov (United States)

    Starkov, Pavel; Jamison, Timothy F; Marek, Ilan

    2015-03-27

    Among the numerous approaches and reagents employed for electrophilic amination, nitrenoids have long stayed out of the limelight. Here, we systematically review the discovery, structural features and chemical reactivity of these promising reagents. We highlight advances in applying the chemistry of nitrenoids as well as outline current limitations and future directions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. O—Maltosylation of Heterocyclic Ketene Aminals

    Institute of Scientific and Technical Information of China (English)

    徐占辉; 黄志镗

    2002-01-01

    The stereoselective synthesis of O-maltosides by reacting benzoyl-substituted heterocyclic ketene aminals 1 or 2 with acetylated maltosyl bromide 3 was investigated.Compounds 1 or 2 reacted with 3 in the presence of mercuric cyanide to give O-maltosides 4 or 5 with E-configuration.While 1 reacted with 3 in the presence of calcium hydride to give O-maltosides 6 with Zconfiguration.

  3. O-Maltosylation of Heterocyclic Ketene Aminals

    Institute of Scientific and Technical Information of China (English)

    XU,Zhan-Hui(徐占辉); HUANG,Zhi-Tang(黄志镗)

    2002-01-01

    The stereoselective synthesis of O-maltosides by reacting benzoyl-substituted heterocyclic ketene aminals 1 or 2 with acetylated maltosyl bromide 3 was investigated. Compounds 1 or 2 reacted with 3 in the presence of mercuric cyanide to give O-maltosides 4 or 5 with E-configuration. While 1 reacted with 3 in the presence of calcium hydride to give O-maltosides 6 with Zconfiguration.

  4. Handling of Copper and Copper Oxide Nanoparticles by Astrocytes.

    Science.gov (United States)

    Bulcke, Felix; Dringen, Ralf

    2016-02-01

    Copper is an essential trace element for many important cellular functions. However, excess of copper can impair cellular functions by copper-induced oxidative stress. In brain, astrocytes are considered to play a prominent role in the copper homeostasis. In this short review we summarise the current knowledge on the molecular mechanisms which are involved in the handling of copper by astrocytes. Cultured astrocytes efficiently take up copper ions predominantly by the copper transporter Ctr1 and the divalent metal transporter DMT1. In addition, copper oxide nanoparticles are rapidly accumulated by astrocytes via endocytosis. Cultured astrocytes tolerate moderate increases in intracellular copper contents very well. However, if a given threshold of cellular copper content is exceeded after exposure to copper, accelerated production of reactive oxygen species and compromised cell viability are observed. Upon exposure to sub-toxic concentrations of copper ions or copper oxide nanoparticles, astrocytes increase their copper storage capacity by upregulating the cellular contents of glutathione and metallothioneins. In addition, cultured astrocytes have the capacity to export copper ions which is likely to involve the copper ATPase 7A. The ability of astrocytes to efficiently accumulate, store and export copper ions suggests that astrocytes have a key role in the distribution of copper in brain. Impairment of this astrocytic function may be involved in diseases which are connected with disturbances in brain copper metabolism.

  5. Iridium- and Ruthenium-Catalyzed N-alkylation of Amines with Alcohols and Amines

    DEFF Research Database (Denmark)

    Lorentz-Petersen, Linda Luise Reeh

    via folding assisted ligation. One segment was synthesised as the C-terminal thioester by Boc-SPPS and the other segment as a C-terminal acid by Fmoc-SPPS. The sites of mutation were all in the α-helical region of the protein and the mutation choices were alanine and Aib, which both posses a high α...... is environmentally benign as it is performed in the absence of both solvent and additives and the only by-product is ammonia. Additionally, the work-up procedure is a simple distillation of the product directly from the reaction mixture. Synthesis of piperazines In the Madsen group it has previously been...... catalysts have been employed for the N-alkylation of amines with either alcohols or amines. Synthesis of secondary amines Self-condensation of primary amines afforded secondary amines in good to high yields. The reaction is catalyzed by the commercially available [Cp*IrCl2]2 complex. The procedure...

  6. Amine Swingbed Payload Testing on ISS

    Science.gov (United States)

    Button, Amy B.; Sweterlitsch, Jeffrey J.

    2014-01-01

    One of NASA Johnson Space Center's test articles of the amine-based carbon dioxide (CO2) and water vapor sorbent system known as the CO2 And Moisture Removal Amine Swing-bed, or CAMRAS, was incorporated into a payload on the International Space Station (ISS). The intent of the payload is to demonstrate the spacecraft-environment viability of the core atmosphere revitalization technology baselined for the new Orion vehicle. In addition to the air blower, vacuum connection, and controls needed to run the CAMRAS, the payload incorporates a suite of sensors for scientific data gathering, a water save function, and an air save function. The water save function minimizes the atmospheric water vapor reaching the CAMRAS unit, thereby reducing ISS water losses that are otherwise acceptable, and even desirable, in the Orion environment. The air save function captures about half of the ullage air that would normally be vented overboard every time the cabin air-adsorbing and space vacuum-desorbing CAMRAS beds swap functions. The JSC team conducted 1000 hours of on-orbit Amine Swingbed Payload testing in 2013 and early 2014. This paper presents the basics of the payload's design and history, as well as a summary of the test results, including comparisons with prelaunch testing.

  7. Rett syndrome - Stimulation of endogenous biogenic amines

    Science.gov (United States)

    Pelligra, R.; Norton, R. D.; Wilkinson, R.; Leon, H. A.; Matson, W. R.

    1992-01-01

    Transient hypercapnic hyperoxemia was induced in two Rett syndrome children by the administration of a gaseous mixture of 80 percent O2 and 20 percent CO2. Time course studies of neurotransmitters and their metabolites showed an immediate and marked increase in central biogenic amine turnover following inhalation of the gas mixture. The increased turnover of biogenic amines was associated with improved clinical changes. This suggests a coupled relationship and provides further support for an etiological role of neurotransmitter dysfunction in Rett syndrome. In a complementary study, elevation of pulmonary CO2 by application of a simple rebreathing device resulted in improvement of abnormal blood gases and elimination of the Cheyne-Stokes-like respiratory pattern of the Rett syndrome. Near normalization of the EEG occurred when a normal respiratory pattern was imposed by means of a respirator. Taken together, these results lead to the preliminary conclusion that cerebral hypoxemia secondary to abnormal respiratory function may contribute to diminished production of biogenic amines in Rett syndrome.

  8. Green Aza-Michael Reaction of Aliphatic Amines to á,(a)-Unsaturated Compounds in Water

    Institute of Scientific and Technical Information of China (English)

    XU Li-Wen; XIA Chun-Gu

    2004-01-01

    The hydroamination of olefins is a long-standing goal for transition metal catalysis. And the metal-catalyzed addition of amines to carbon-carbon double bonds is an unsolved, synthetically important problem. Although recent advances have made using lanthanide and precious metal complexes, there are few excellent catalyst that display broad functional group tolerance and useful rates for an intermolecular aza-Michael addition. As such, the development of efficient synthetic methods leading to a-amino carbonyl compounds and derivatives has attracted much attention in organic synthesis. Although recent advances have made this route more attractive, development of cheaper, simpler, and more efficient metal catalyst is highly desirable. We also have been interested in developing a reaction that uses catalytic quantities of minimally toxic, readily available, economic reagent should greatly contribute to the creation of environmental benign processes.The recent interest in aqueous medium metal-mediated carbon-carbon and carbon-heteroatom and formations led to the contributors for such reactions. Furthermore, development of organic reactions in water will contribute to the progress of green and quasi-nature catalysis chemistry. Surprisingly however, there is few report on conjugate additions of amines to a,a-unsaturated carbonyl compounds in water.Herein, we report a new protocol that employs air stable copper salts as efficient catalyst in the aza-Michael reaction under mild reaction conditions. Advantages of the protocol include high-yielding reactions that can be conducted at ambient temperature; the use of readily available and stable copper salts as the catalyst, and the reaction was successfully performed in environmental benign solvent, water.Finally, we have utilized a variety of aliphatic amines successfully with different á,(a)-unsaturated compounds catalyzed by simple hydrophilic ionic liquid, bmimBF4 in water. Interestingly, all the aliphatic amines gave

  9. A role for NADPH oxidase in antigen presentation

    Directory of Open Access Journals (Sweden)

    Gail J Gardiner

    2013-09-01

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

  10. Canine models of copper toxicosis for understanding mammalian copper metabolism

    OpenAIRE

    Fieten, Hille; Leegwater, Peter A. J.; Watson, Adrian L.; Rothuizen, Jan

    2011-01-01

    Hereditary forms of copper toxicosis exist in man and dogs. In man, Wilson’s disease is the best studied disorder of copper overload, resulting from mutations in the gene coding for the copper transporter ATP7B. Forms of copper toxicosis for which no causal gene is known yet are recognized as well, often in young children. Although advances have been made in unraveling the genetic background of disorders of copper metabolism in man, many questions regarding disease mechanisms and copper homeo...

  11. Extraction of Copper(I Thiosulfate by Modified Chitosan

    Directory of Open Access Journals (Sweden)

    Okky Anggraito

    2013-12-01

    Full Text Available Chitosan is one of non-toxic natural biopolymer and abundance in nature. Chitosan have two active sites such as amine and hydroxyl groups. Amine groups (-NH2 in chitosan can be modified into secondary amine (-NHR. In this research, copper was dissolved as copper(I thiosulfate as anion complex (Cu(S2O323- and chitosan was modified by trimethylamine sulfur trioxide (TMAS. One of hydrogen atom in –NH2 was substituted by –SO3Na. The result of this research, the modified chitosan was identified by FT-IR. FT-IR spectra gave characteristic band at 3600-3200 cm-1 (O-H and N-H; 1648 cm-1 (C=O; 1115,74 cm-1 (S=O and 617,18 cm-1 (N-S. The result of surface analysis using SEM and TEM showed that the surface morphology of sulfated chitosan as a result of modification is different in comparison with chitosan. Based on chitosan, pH extraction was adjusted to pH 3 until 8. After optimum pH of extraction was obtained then re-extraction was done by using thiosulfate solution at 0.05 ; 0.10 ; 0.50 ; and 1.00 M. Extraction and re-extraction of copper(I thiosulfate was analyzed by Atomic Absorption Spectrophotometer (AAS. The highest efficiency extraction using modified chitosan and chitosan respectively at pH 3 and 6. The efficiency re-extraction using modified chitosan and chitosan respectively 100% and below 100%.

  12. Extraction of Copper(I Thiosulfate by Modified Chitosan

    Directory of Open Access Journals (Sweden)

    Okky Anggraito

    2014-06-01

    Full Text Available Chitosan is one of non-toxic natural biopolymer and abundance in nature. Chitosan have two active sites such as amine and hydroxyl groups. Amine groups (-NH2 in chitosan can be modified into secondary amine (-NHR. In this research, copper was dissolved as copper(I thiosulfate as anion complex (Cu(S2O323- and chitosan was modified by trimethylamine sulfur trioxide (TMAS. One of hydrogen atom in –NH2 was substituted by –SO3Na. The result of this research, the modified chitosan was identified by FT-IR. FT-IR spectra gave characteristic band at 3600-3200 cm-1 (O-H and N-H; 1648 cm-1 (C=O; 1115,74 cm-1 (S=O and 617,18 cm-1 (N-S. The result of surface analysis using SEM and TEM showed that the surface morphology of sulfated chitosan as a result of modification is different in comparison with chitosan. Based on chitosan, pH extraction was adjusted to pH 3 until 8. After optimum pH of extraction was obtained then re-extraction was done by using thiosulfate solution at 0.05 ; 0.10 ; 0.50 ; and 1.00 M. Extraction and re-extraction of copper(I thiosulfate was analyzed by Atomic Absorption Spectrophotometer (AAS. The highest efficiency extraction using modified chitosan and chitosan respectively at pH 3 and 6. The efficiency re-extraction using modified chitosan and chitosan respectively 100% and below 100%.

  13. Unexpected role of the copper transporter ATP7A in PDGF-induced vascular smooth

    Energy Technology Data Exchange (ETDEWEB)

    Ashino, T.; Varadarajan, S.; Urao, N.; Oshikawa, J.; Chen, G. -F.; Wang, H.; Huo, Y.; Finney, L.; Vogt, S.; McKinney, R. D.; Maryon, E. B.; Kaplan, J. H.; Ushio-Fukai, M.; Fukai, T. (Biosciences Division); ( XSD); ( PSC-USR); (Univ. of Illinois at Chicago); (Univ. of Minnesota)

    2010-09-09

    Copper, an essential nutrient, has been implicated in vascular remodeling and atherosclerosis with unknown mechanism. Bioavailability of intracellular copper is regulated not only by the copper importer CTR1 (copper transporter 1) but also by the copper exporter ATP7A (Menkes ATPase), whose function is achieved through copper-dependent translocation from trans-Golgi network (TGN). Platelet-derived growth factor (PDGF) promotes vascular smooth muscle cell (VSMC) migration, a key component of neointimal formation. To determine the role of copper transporter ATP7A in PDGF-induced VSMC migration. Depletion of ATP7A inhibited VSMC migration in response to PDGF or wound scratch in a CTR1/copper-dependent manner. PDGF stimulation promoted ATP7A translocation from the TGN to lipid rafts, which localized at the leading edge, where it colocalized with PDGF receptor and Rac1, in migrating VSMCs. Mechanistically, ATP7A small interfering RNA or CTR small interfering RNA prevented PDGF-induced Rac1 translocation to the leading edge, thereby inhibiting lamellipodia formation. In addition, ATP7A depletion prevented a PDGF-induced decrease in copper level and secretory copper enzyme precursor prolysyl oxidase (Pro-LOX) in lipid raft fraction, as well as PDGF-induced increase in LOX activity. In vivo, ATP7A expression was markedly increased and copper accumulation was observed by synchrotron-based x-ray fluorescence microscopy at neointimal VSMCs in wire injury model. These findings suggest that ATP7A plays an important role in copper-dependent PDGF-stimulated VSMC migration via recruiting Rac1 to lipid rafts at the leading edge, as well as regulating LOX activity. This may contribute to neointimal formation after vascular injury. Our findings provide insight into ATP7A as a novel therapeutic target for vascular remodeling and atherosclerosis.

  14. A Study on Some Copper(Ⅱ) Complexes of Polyaza Cryptandsand Planar Macrocycles-Synthesis, Characterization and Superoxide Dismutase Activity

    Institute of Scientific and Technical Information of China (English)

    GAO, You-Liang; SHEN, Cheng-Yu; TANG, Yin-Yan; LUO, Qin-Hui; YU, Shu-Yan

    2001-01-01

    Two kinds of macrocyclic copper(Ⅱ) complexes were synthesized. One of them is composed of copper(Ⅱ) cryptates of ligands L1-L4 which are condensation products of 5-R-2methoxy-1,3-phenyldialdehyde (R= OCH3, L1) with tris(2-aminoethyl)amine and 5-R-2-methothoxy-1, 3-phenyldialdehyde (R = CH3, L3) with tris(2-aminopropyi)amine as well as their reduced products of L1 and L3 (L2 and L4). The other is composed of two-dimensional macrocyclic copper(Ⅱ) complexcs of ligands L5-L8 of condensation products of diethylene triamine with 4-R-1-methoxy-2, 6-phenyldialdehyde (R = Cl,Br, CH3, OCH3). Therelationship between their structurcs and superoxide dismutase (SOD) activity was investigated.The results can provide some clues to the synthesis of SOD mimics.

  15. Hair copper in intrauterine copper device users.

    Science.gov (United States)

    Thiery, M; Heyndrickx, A; Uyttersprot, C

    1984-03-01

    The antifertility effect of copper-bearing IUDs is based on continuous release of copper, which is a result of the reaction between the metal and the uterine secretions. Released cupric ions collect in the endometrium and in the uterine fluid but significant accumulation has not been found in the bloodstream or elsewhere. Following Laker's suggestion that hair be used for monitoring essential trace elements, e.g., copper, we checked the copper content of the hair of women wearing copper-bearing IUDs. Samples of untreated pubic hair removed by clipping before diagnostic curettage were obtained from 10 young (24-34 years old), white caucasian females who until then had been wearing an MLCu250 IUD for more than 1 year. Pubes from 10 comparable (sex, age, race) subjects who had never used a Cu-containing device served as controls. The unwashed material was submitted to the toxicology laboratory, where the copper content was assessed by flameless atomic absorption, a technique whose lower limit of measurement lies at a concentration of 0.05 mcg Cu/ml fluid (50 ppb). Hair samples were washed to remove extraneous traces of metal according to the prescriptions of the International Atomic Energy Agency, weighed, and mineralized, after which a small volume (10 mcl) of the diluted fluid was fed into the graphite furnace. Each sample (75-150 mg) was analyzed 4 times, both before and after washing. Since the cleaning procedure reduces the weight of the sample (mainly by the removal of fat, dust, etc.) this explains why the percentage copper content of washed hair is higher than that of unwashed hair belonging to the same subject. The results indicate that there was no significant difference (Mann-Whitney U test) between the mean copper levels of both unwashed and washed pubes from women who were using or had never used an MLCu250 IUD. We therefore conclude that the use of this copper-containing device is not associated with significant accumulation of copper in (pubic) hair.

  16. China Copper Processing Industry Focus

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>1. Market Consumption The ’China Factor’ and Copper Price Fluctuation We all know China is an enormous consumer of copper,but the exact levels of consumption and where the copper has gone remains a mystery.

  17. Biogenic nanoparticles: copper, copper oxides, copper sulphides, complex copper nanostructures and their applications.

    Science.gov (United States)

    Rubilar, Olga; Rai, Mahendra; Tortella, Gonzalo; Diez, Maria Cristina; Seabra, Amedea B; Durán, Nelson

    2013-09-01

    Copper nanoparticles have been the focus of intensive study due to their potential applications in diverse fields including biomedicine, electronics, and optics. Copper-based nanostructured materials have been used in conductive films, lubrification, nanofluids, catalysis, and also as potent antimicrobial agent. The biogenic synthesis of metallic nanostructured nanoparticles is considered to be a green and eco-friendly technology since neither harmful chemicals nor high temperatures are involved in the process. The present review discusses the synthesis of copper nanostructured nanoparticles by bacteria, fungi, and plant extracts, showing that biogenic synthesis is an economically feasible, simple and non-polluting process. Applications for biogenic copper nanoparticles are also discussed.

  18. Analysis of structure-function relationships in cytochrome c oxidase and its biomimetic analogs via resonance Raman and surface enhanced resonance Raman spectroscopies.

    Science.gov (United States)

    Weidinger, Inez M

    2015-01-01

    Cytochrome c oxidase (CcO) catalyzes the four electron reduction of molecular oxygen to water while avoiding the formation of toxic peroxide; a quality that is of high relevance for the development of oxygen-reducing catalysts. Resonance Raman spectroscopy has been used since many years as a technique to identify electron transfer pathways in cytochrome c oxidase and to identify the key intermediates in the catalytic cycle. This information can be compared to artificial systems such as modified heme-copper enzymes, molecular heme-copper catalysts or CcO/electrode complexes in order to shed light into the reaction mechanism of these non-natural systems. Understanding the structural commonalities and differences of CcO with its non-natural analogs is of great value for designing efficient oxygen-reducing catalysts. In this review therefore Raman spectroscopic measurements on artificial heme-copper enzymes and model complexes are summarized and compared to the natural enzyme cytochrome c oxidase. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems.

  19. Xanthine oxidase biosensor for monitoring meat spoilage

    Science.gov (United States)

    Vanegas, D. C.; Gomes, C.; McLamore, E. S.

    2014-05-01

    In this study, we have designed an electrochemical biosensor for real-time detection of specific biomarkers of bacterial metabolism related to meat spoilage (hypoxanthine and xanthine). The selective biosensor was developed by assembling a `sandwich' of nanomaterials and enzymes on a platinum-iridium electrode (1.6 mm tip diameter). The materials deposited on the sensor tip include amorphous platinum nanoclusters (i.e. Pt black), reduced graphene oxide, nanoceria, and xanthine oxidase. Xanthine oxidase was encapsulated in laponite hydrogel and used for the biorecognition of hypoxanthine and xanthine (two molecules involved in the rotting of meat by spoilage microorganisms). The developed biosensor demonstrated good electrochemical performance toward xanthine with sensitivity of 2.14 +/- 1.48 μA/mM, response time of 5.2 +/- 1.5 sec, lower detection limit of 150 +/- 39 nM, and retained at least 88% of its activity after 7 days of continuous use.

  20. Plasma diamine oxidase activity in asthmatic children

    Directory of Open Access Journals (Sweden)

    Kyoichiro Toyoshima

    1996-01-01

    Full Text Available Histamine plays an important role in the development of asthmatic symptoms. Diamine oxidase (DAO histaminase, which inactivates histamine, is located in the intestine and kidney and is released into plasma. Plasma DAO activity in asthmatic children was measured by a recently developed high performance liquid chromatographic method using histamine as the DAO substrate. Diamine oxidase activity was higher in severely asthmatic children than in those with mild asthma. A time course study during the acute exacerbation phase revealed that DAO activity rose during acute asthmatic attacks and then decreased gradually over several days. Although the mechanisms of plasma DAO activity increase during acute asthmatic attacks could not be explained, data showed that plasma DAO activity is an important index of histamine metabolism in asthmatics and may relate to some mechanisms of acute exacerbation of airway inflammation. Consequently, fluctuations in plasma DAO can be used as one of various indices of instability in management of asthma.

  1. Distinct functional roles for the Menkes and Wilson copper translocating P-type ATPases in human placental cells.

    Science.gov (United States)

    Hardman, Belinda; Michalczyk, Agnes; Greenough, Mark; Camakaris, James; Mercer, Jjulian; Ackland, Leigh

    2007-01-01

    The copper transporting ATPases, Menkes (ATP7A; MNK) and Wilson (ATP7B; WND) are essential for normal copper transport in the human body. The placenta is the key organ in copper supply to the fetus during pregnancy and it is one of the few organs in the body to express both of the ATPases. The placenta therefore provides a unique opportunity to elucidate the specific roles of these transporters within the one cell type. Using polarized placental Jeg-3 cells, siRNA technology and radio-labelled 64Cu transport assays, MNK and WND were shown to have distinct roles in the vectorial transport of copper. MNK transported copper from the cell via the basolateral membrane and in contrast, WND transported copper from the apical membrane. Inactivation of MNK resulted in decreased activity of two important cuproenzymes, lysyl oxidase and Cu/Zn-superoxide dismutase. Overall, these results provide definitive evidence for distinct roles of MNK and WND in the human placenta, and are consistent with a role for MNK in the transport of copper into the fetal circulation, and through delivery of copper to placental cuproenzymes, whilst WND contributes to the maintenance of placental copper homeostasis by transporting copper to the maternal circulation.

  2. The tachykinin peptide neurokinin B binds copper forming an unusual [CuII(NKB)2] complex and inhibits copper uptake into 1321N1 astrocytoma cells.

    Science.gov (United States)

    Russino, Debora; McDonald, Elle; Hejazi, Leila; Hanson, Graeme R; Jones, Christopher E

    2013-10-16

    Neurokinin B (NKB) is a member of the tachykinin family of neuropeptides that have neuroinflammatory, neuroimmunological, and neuroprotective functions. In a neuroprotective role, tachykinins can help protect cells against the neurotoxic processes observed in Alzheimer's disease. A change in copper homeostasis is a clear feature of Alzheimer's disease, and the dysregulation may be a contributory factor in toxicity. Copper has recently been shown to interact with neurokinin A and neuropeptide γ and can lead to generation of reactive oxygen species and peptide degradation, which suggests that copper may have a place in tachykinin function and potentially misfunction. To explore this, we have utilized a range of spectroscopic techniques to show that NKB, but not substance P, can bind Cu(II) in an unusual [Cu(II)(NKB)2] neutral complex that utilizes two N-terminal amine and two imidazole nitrogen ligands (from each molecule of NKB) and the binding substantially alters the structure of the peptide. Using 1321N1 astrocytoma cells, we show that copper can enter the cells and subsequently open plasma membrane calcium channels but when bound to neurokinin B copper ion uptake is inhibited. This data suggests a novel role for neurokinin B in protecting cells against copper-induced calcium changes and implicates the peptide in synaptic copper homeostasis.

  3. Process characterization of a monoamine oxidase

    DEFF Research Database (Denmark)

    Ramesh, Hemalata; Woodley, John

    2014-01-01

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

  4. Imaging Monoamine Oxidase in the Human Brain

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-11-10

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

  5. The inhibition of monoamine oxidase by esomeprazole

    OpenAIRE

    2013-01-01

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

  6. New potential of the reductive alkylation of amines

    Science.gov (United States)

    Gusak, K. N.; Ignatovich, Zh V.; Koroleva, E. V.

    2015-03-01

    Available data on the reductive alkylation of amines with carbonyl compounds — a key method for the preparation of secondary and tertiary amines — are described systematically. The review provides information on the relevant reducing agents and catalysts and on the use of chiral catalysts in stereo- and enantiocontrolled reactions of amine synthesis. The effect of the reactant and catalyst structures on the reaction rates and chemo- and stereo(enantio)selectivity is considered. The bibliography includes 156 references.

  7. COX19 mediates the transduction of a mitochondrial redox signal from SCO1 that regulates ATP7A-mediated cellular copper efflux

    Science.gov (United States)

    Leary, Scot C.; Cobine, Paul A.; Nishimura, Tamiko; Verdijk, Robert M.; de Krijger, Ronald; de Coo, René; Tarnopolsky, Mark A.; Winge, Dennis R.; Shoubridge, Eric A.

    2013-01-01

    SCO1 and SCO2 are metallochaperones whose principal function is to add two copper ions to the catalytic core of cytochrome c oxidase (COX). However, affected tissues of SCO1 and SCO2 patients exhibit a combined deficiency in COX activity and total copper content, suggesting additional roles for these proteins in the regulation of cellular copper homeostasis. Here we show that both the redox state of the copper-binding cysteines of SCO1 and the abundance of SCO2 correlate with cellular copper content and that these relationships are perturbed by mutations in SCO1 or SCO2, producing a state of apparent copper overload. The copper deficiency in SCO patient fibroblasts is rescued by knockdown of ATP7A, a trans-Golgi, copper-transporting ATPase that traffics to the plasma membrane during copper overload to promote efflux. To investigate how a signal from SCO1 could be relayed to ATP7A, we examined the abundance and subcellular distribution of several soluble COX assembly factors. We found that COX19 partitions between mitochondria and the cytosol in a copper-dependent manner and that its knockdown partially rescues the copper deficiency in patient cells. These results demonstrate that COX19 is necessary for the transduction of a SCO1-dependent mitochondrial redox signal that regulates ATP7A-mediated cellular copper efflux. PMID:23345593

  8. Copper deficiency leads to anemia, duodenal hypoxia, upregulation of HIF-2α and altered expression of iron absorption genes in mice.

    Science.gov (United States)

    Matak, Pavle; Zumerle, Sara; Mastrogiannaki, Maria; El Balkhi, Souleiman; Delga, Stephanie; Mathieu, Jacques R R; Canonne-Hergaux, François; Poupon, Joel; Sharp, Paul A; Vaulont, Sophie; Peyssonnaux, Carole

    2013-01-01

    Iron and copper are essential trace metals, actively absorbed from the proximal gut in a regulated fashion. Depletion of either metal can lead to anemia. In the gut, copper deficiency can affect iron absorption through modulating the activity of hephaestin - a multi-copper oxidase required for optimal iron export from enterocytes. How systemic copper status regulates iron absorption is unknown. Mice were subjected to a nutritional copper deficiency-induced anemia regime from birth and injected with copper sulphate intraperitoneally to correct the anemia. Copper deficiency resulted in anemia, increased duodenal hypoxia and Hypoxia inducible factor 2α (HIF-2α) levels, a regulator of iron absorption. HIF-2α upregulation in copper deficiency appeared to be independent of duodenal iron or copper levels and correlated with the expression of iron transporters (Ferroportin - Fpn, Divalent Metal transporter - Dmt1) and ferric reductase - Dcytb. Alleviation of copper-dependent anemia with intraperitoneal copper injection resulted in down regulation of HIF-2α-regulated iron absorption genes in the gut. Our work identifies HIF-2α as an important regulator of iron transport machinery in copper deficiency.

  9. Nanotextured metal copper substrates as powerful and long-lasting fuel cell anodes.

    Science.gov (United States)

    Filanovsky, Boris; Granot, Eran; Dirawi, Rawi; Presman, Igor; Kuras, Iliya; Patolsky, Fernando

    2011-04-13

    Fuel cells (FCs) are promising electrochemical devices that convert chemical energy of fuels directly into electrical energy. We present a new anode material based on nanotextured metal copper for fuel cell applications. We have demonstrated that low-cost copper catalyst anodes act as highly efficient and ultra-long-lasting materials for the direct electro-oxidation of ammonia-borane and additional amine derivatives. High power densities of ca. 1W·cm(-2) (ca. -1 V vs Ag/AgCl at 1 A) are readily achieved at room temperature. We fabricate fuel cell devices based on our nanotextured Cu anodes in combination with commercial air cathodes.

  10. Copper and silver halates

    CERN Document Server

    Woolley, EM; Salomon, M

    2013-01-01

    Copper and Silver Halates is the third in a series of four volumes on inorganic metal halates. This volume presents critical evaluations and compilations for halate solubilities of the Group II metals. The solubility data included in this volume are those for the five compounds, copper chlorate and iodate, and silver chlorate, bromate and iodate.

  11. Coping with copper

    DEFF Research Database (Denmark)

    Nunes, Ines; Jacquiod, Samuel; Brejnrod, Asker

    2016-01-01

    Copper has been intensively used in industry and agriculture since mid-18(th) century and is currently accumulating in soils. We investigated the diversity of potential active bacteria by 16S rRNA gene transcript amplicon sequencing in a temperate grassland soil subjected to century-long exposure......, suggesting a potential promising role as bioindicators of copper contamination in soils....

  12. Amines and amine-related compounds in surface waters: a review of sources, concentrations and aquatic toxicity.

    Science.gov (United States)

    Poste, Amanda E; Grung, Merete; Wright, Richard F

    2014-05-15

    This review compiles available information on the concentrations, sources, fate and toxicity of amines and amine-related compounds in surface waters, including rivers, lakes, reservoirs, wetlands and seawater. There is a strong need for this information, especially given the emergence of amine-based post-combustion CO2 capture technologies, which may represent a new and significant source of amines to the environment. We identify a broad range of anthropogenic and natural sources of amines, nitrosamines and nitramines to the aquatic environment, and identify some key fate and degradation pathways of these compounds. There were very few data available on amines in surface waters, with reported concentrations often below detection and only rarely exceeding 10 μg/L. Reported concentrations for seawater and reservoirs were below detection or very low, while for lakes and rivers, concentrations spanned several orders of magnitude. The most prevalent and commonly detected amines were methylamine (MA), dimethylamine (DMA), ethylamine (EA), diethylamine (DEA) and monoethanolamine (MEAT). The paucity of data may reflect the analytical challenges posed by determination of amines in complex environmental matrices at ambient levels. We provide an overview of available aquatic toxicological data for amines and conclude that at current environmental concentrations, amines are not likely to be of toxicological concern to the aquatic environment, however, the potential for amines to act as precursors in the formation of nitrosamines and nitramines may represent a risk of contamination of drinking water supplies by these often carcinogenic compounds. More research on the prevalence and toxicity of amines, nitrosamines and nitramines in natural waters is necessary before the environmental impact of new point sources from carbon capture facilities can be adequately quantified.

  13. Copper-catalyzed intermolecular trifluoromethylazidation of alkenes: convenient access to CF3 -containing alkyl azides.

    Science.gov (United States)

    Wang, Fei; Qi, Xiaoxu; Liang, Zhaoli; Chen, Pinhong; Liu, Guosheng

    2014-02-10

    A novel copper-catalyzed intermolecular trifluoromethylazidation of alkenes has been developed under mild reaction conditions. A variety of CF3 -containing organoazides were directly synthesized from a wide range of olefins, including activated and unactivated alkenes, and the resulting products can be easily transformed into the corresponding CF3 -containing amine derivatives. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

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

    2010-02-10

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

  15. Amine reactivity with charged sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    B. R. Bzdek

    2011-05-01

    Full Text Available The distribution of ionic species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS. Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge, both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia are also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4(H2SO4x] and [(NH4x(HSO4x+1(H2SO43]. Dimethylamine substitution for ammonia in [(NH4x(HSO4x+1(H2SO43] clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4(H2SO4x]clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (> m/z 400, whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2–3 orders of magnitude slower than incorporation of dimethylamine either by

  16. Antibacterial activity of novel benzopolycyclic amines.

    Science.gov (United States)

    Barniol-Xicota, Marta; Escandell, Alex; Valverde, Elena; Julián, Esther; Torrents, Eduard; Vázquez, Santiago

    2015-01-15

    Staphylococcus aureus, especially strains resistant to multiple antibiotics, is a major pathogen for humans and animals. In this paper we have synthesized and evaluated the antibacterial activity of a new series of benzopolycyclic amines. Some of them exhibited μM MIC values against Staphylococcus aureus and other bacteria, including methicillin-resistant S. aureus MRSA. Compound 8 that displayed a good selectivity index, showed to be active in eliminating bacterial cells forming a preexisting biofilm. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Amine reactivity with charged sulfuric acid clusters

    Directory of Open Access Journals (Sweden)

    B. R. Bzdek

    2011-08-01

    Full Text Available The distribution of charged species produced by electrospray of an ammonium sulfate solution in both positive and negative polarities is examined using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS. Positively-charged ammonium bisulfate cluster composition differs significantly from negatively-charged cluster composition. For positively-charged clusters all sulfuric acid is neutralized to bisulfate, whereas for negatively-charged clusters the degree of sulfuric acid neutralization is cluster size-dependent. With increasing cluster size (and, therefore, a decreasing role of charge, both positively- and negatively-charged cluster compositions converge toward ammonium bisulfate. The reactivity of negatively-charged sulfuric acid-ammonia clusters with dimethylamine and ammonia is also investigated by FTICR-MS. Two series of negatively-charged clusters are investigated: [(HSO4(H2SO4x] and [(NH4x(HSO4x+1(H2SO43]. Dimethylamine substitution for ammonia in [(NH4 x(HSO4 x+1(H2SO43] clusters is nearly collision-limited, and subsequent addition of dimethylamine to neutralize H2SO4 to bisulfate is within one order of magnitude of the substitution rate. Dimethylamine addition to [(HSO4 (H2SO4 x] clusters is either not observed or very slow. The results of this study indicate that amine chemistry will be evident and important only in large ambient negative ions (>m/z 400, whereas amine chemistry may be evident in small ambient positive ions. Addition of ammonia to unneutralized clusters occurs at a rate that is ~2–3 orders of magnitude slower than incorporation of dimethylamine either by substitution or addition

  18. Controlling Nitrosamines, Nitramines, and Amines in Amine-Based CO₂ Capture Systems with Continuous Ultraviolet and Ozone Treatment of Washwater.

    Science.gov (United States)

    Dai, Ning; Mitch, William A

    2015-07-21

    Formation of nitrosamines and nitramines from reactions between flue gas NOx and the amines used in CO2 capture units has arisen as a significant concern. Washwater scrubbers can capture nitrosamines and nitramines. They can also capture amines, preventing formation of nitrosamines and nitramines downwind by amine reactions with ambient NOx. The continuous application of UV alone, or a combination of UV and ozone to the return line of a washwater treatment unit was evaluated to control the accumulation of nitrosamines, nitramines and amines in a laboratory-scale washwater unit. With model secondary amine solvents ranging from nonvolatile diethanolamine to volatile morpholine, application of 272-537 mJ/cm(2) UV incident fluence alone reduced the accumulation of nitrosamines and nitramines by approximately an order of magnitude. Modeling indicated that the gains achieved by UV treatment should increase over time, because UV treatment converts the time dependence of nitrosamine accumulation from a quadratic to a linear function. Ozone (21 mg/L) maintained low steady-state concentrations of amines in the washwater. While modeling indicated that more than 80% of nitrosamine accumulation in the washwater was associated with reaction of washwater amines with residual NOx, a reduction in nitrosamine accumulation rates due to ozone oxidation of amines was not fully realized because the ozonation products of amines reduced nitrosamine photolysis rates by competing for photons.

  19. Kunpeng Copper:The largest Copper Smelting Company of Sichuan

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>On September 9,Liangshan Mining Company’s 100,000 tons/year cathode copper project kicked off.It is another key project of the company following the successful launch of the 100,000 tons/year anode copper project.Based on ISA copper smelting technology of the largest open-cast copper mine in southwest China,

  20. Trace Amines and the Trace Amine-Associated Receptor 1: Pharmacology, Neurochemistry, and Clinical Implications.

    Science.gov (United States)

    Pei, Yue; Asif-Malik, Aman; Canales, Juan J

    2016-01-01

    Biogenic amines are a collection of endogenous molecules that play pivotal roles as neurotransmitters and hormones. In addition to the "classical" biogenic amines resulting from decarboxylation of aromatic acids, including dopamine (DA), norepinephrine, epinephrine, serotonin (5-HT), and histamine, other biogenic amines, present at much lower concentrations in the central nervous system (CNS), and hence referred to as "trace" amines (TAs), are now recognized to play significant neurophysiological and behavioral functions. At the turn of the century, the discovery of the trace amine-associated receptor 1 (TAAR1), a phylogenetically conserved G protein-coupled receptor that is responsive to both TAs, such as β-phenylethylamine, octopamine, and tyramine, and structurally-related amphetamines, unveiled mechanisms of action for TAs other than interference with aminergic pathways, laying the foundations for deciphering the functional significance of TAs and its mammalian CNS receptor, TAAR1. Although, its molecular interactions and downstream targets have not been fully elucidated, TAAR1 activation triggers accumulation of intracellular cAMP, modulates PKA and PKC signaling and interferes with the β-arrestin2-dependent pathway via G protein-independent mechanisms. TAAR1 is uniquely positioned to exert direct control over DA and 5-HT neuronal firing and release, which has profound implications for understanding the pathophysiology of, and therefore designing more efficacious therapeutic interventions for, a range of neuropsychiatric disorders that involve aminergic dysregulation, including Parkinson's disease, schizophrenia, mood disorders, and addiction. Indeed, the recent development of novel pharmacological tools targeting TAAR1 has uncovered the remarkable potential of TAAR1-based medications as new generation pharmacotherapies in neuropsychiatry. This review summarizes recent developments in the study of TAs and TAAR1, their intricate neurochemistry and

  1. Prevention of melanin formation during aryl alcohol oxidase production under growth-limited conditions using an Aspergillus nidulans cell factory.

    Science.gov (United States)

    Pardo-Planas, Oscar; Prade, Rolf A; Müller, Michael; Atiyeh, Hasan K; Wilkins, Mark R

    2017-11-01

    An Aspergillus nidulans cell factory was genetically engineered to produce an aryl alcohol oxidase (AAO). The cell factory initiated production of melanin when growth-limited conditions were established using stationary plates and shaken flasks. This phenomenon was more pronounced when the strain was cultured in a trickle bed reactor (TBR). This study investigated different approaches to reduce melanin formation in fungal mycelia and liquid medium in order to increase the enzyme production yield. Removal of copper from the medium recipe reduced melanin formation in agar cultures and increased enzyme activities by 48% in agitated liquid cultures. Copper has been reported as a key element for tyrosinase, an enzyme responsible for melanin production. Ascorbic acid (0.44g/L) stopped melanin accumulation, did not affect growth parameters and resulted in AAO activity that was more than two-fold greater than a control treatment with no ascorbic acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The nature of CuA in cytochrome c oxidase

    OpenAIRE

    Stevens, Tom H.; Martin, Craig T.; Wang, Hsin; Brudvig, Gary W.; Scholes, Charles P.; Chan, Sunney I.

    1982-01-01

    The isolation and purification of yeast cytochrome c oxidase is described. Characterization of the purified protein indicates that it is spectroscopically identical with cytochrome c oxidase isolated from beef heart. Preparations of isotopically substituted yeast cytochrome c oxidase are obtained incorporating [1,3-15N2]histidine or [beta,beta- 2H2]cysteine. Electron paramagnetic resonance and electron nuclear double resonance spectra of the isotopically substituted proteins identify unambigu...

  3. Preparation and characterization of amine-functionalized sugarcane bagasse for CO2 capture.

    Science.gov (United States)

    Luo, Shihe; Chen, Siyu; Chen, Shuixia; Zhuang, Linzhou; Ma, Nianfang; Xu, Teng; Li, Qihan; Hou, Xunan

    2016-03-01

    A low-cost solid amine adsorbent for CO2 capture was prepared by using sugarcane bagasse (SB), a dominant agro-industrial residue in the sugar and alcohol industry as raw materials. In this preparation process, acrylamide was grafted on SB, and the grafted fiber was then aminated with different type of amine reagents to introduce primary and secondary amine groups onto the surface of SB fibers. The graft and amination conditions were optimized. The prepared solid amine adsorbent showed remarkable CO2 adsorption capacity and the adsorption capacity of the solid amine adsorbent could reach 5.01 mmol CO2/g at room temperature. The comparison of adsorption capacities of amine fibers aminated with various amination agents demonstrated that fibers aminated with triethylenetetramine would obtain higher adsorption capacities and higher amine efficiency. These adsorbents also showed good regeneration performance, the regenerated adsorbent could maintain almost the same adsorption capacity for CO2 after 10 recycles.

  4. Thermodynamics of organic mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)]. E-mail: jagl@termo.uva.es; Mozo, Ismael [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Fuente, Isaias Garcia de la [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)

    2006-02-01

    Binary mixtures containing pyridine (PY), or 2-methylpyridine (2MPY) or 3-methylpyridine (3MPY) or 4-methylpyridine (4MPY) and an organic solvent as benzene, toluene, alkane, or 1-alkanol are investigated in the framework of DISQUAC. The corresponding interaction parameters are reported. The model describes accurately a whole set of thermodynamic properties: vapor-liquid equilibria (VLE), liquid-liquid equilibria (LLE), solid-liquid equilibria (SLE), molar excess Gibbs energies (G{sup E}), molar excess enthalpies (H{sup E}), molar excess heat capacities at constant pressure (C{sub P}{sup E}) and the concentration-concentration structure factor (S{sub CC}(0)). It is remarkable that DISQUAC correctly predicts the W-shaped curve of the C{sub P}{sup E} of the pyridine + n-hexadecane system. The model can be applied successfully to mixtures with strong positive or negative deviations from the Raoult's law. DISQUAC improves the theoretical results from UNIFAC (Dortmund version). The replacement of pyridine by a methylpyridine leads to a weakening of the amine-amine interactions, ascribed to the steric effect caused by the methyl group attached to the aromatic ring. This explains that for a given solvent (alkane, 1-alkanol) H{sup E}(pyridine)>H{sup E}(methylpyridine)

  5. The Arabidopsis COX11 Homolog is Essential for Cytochrome c Oxidase Activity.

    Science.gov (United States)

    Radin, Ivan; Mansilla, Natanael; Rödel, Gerhard; Steinebrunner, Iris

    2015-01-01

    Members of the ubiquitous COX11 (cytochrome c oxidase 11) protein family are involved in copper delivery to the COX complex. In this work, we characterize the Arabidopsis thaliana COX11 homolog (encoded by locus At1g02410). Western blot analyses and confocal microscopy identified Arabidopsis COX11 as an integral mitochondrial protein. Despite sharing high sequence and structural similarities, the Arabidopsis COX11 is not able to functionally replace the Saccharomyces cerevisiae COX11 homolog. Nevertheless, further analysis confirmed the hypothesis that Arabidopsis COX11 is essential for COX activity. Disturbance of COX11 expression through knockdown (KD) or overexpression (OE) affected COX activity. In KD lines, the activity was reduced by ~50%, resulting in root growth inhibition, smaller rosettes and leaf curling. In OE lines, the reduction was less pronounced (~80% of the wild type), still resulting in root growth inhibition. Additionally, pollen germination was impaired in COX11 KD and OE plants. This effect on pollen germination can only partially be attributed to COX deficiency and may indicate a possible auxiliary role of COX11 in ROS metabolism. In agreement with its role in energy production, the COX11 promoter is highly active in cells and tissues with high-energy demand for example shoot and root meristems, or vascular tissues of source and sink organs. In COX11 KD lines, the expression of the plasma-membrane copper transporter COPT2 and of several copper chaperones was altered, indicative of a retrograde signaling pathway pertinent to copper homeostasis. Based on our data, we postulate that COX11 is a mitochondrial chaperone, which plays an important role for plant growth and pollen germination as an essential COX complex assembly factor.

  6. Posttranslational regulation of copper transporters

    NARCIS (Netherlands)

    van den Berghe, P.V.E.

    2009-01-01

    The transition metal copper is an essential cofactor for many redox-active enzymes, but excessive copper can generate toxic reactive oxygen species. Copper homeostasis is maintained by highly conserved proteins, to balance copper uptake, distribution and export on the systemic and cellular level. Th

  7. ELPI+ measurements of aerosol growth in an amine absorption column

    NARCIS (Netherlands)

    Mertens, J.; Brachert, L.; Desagher, D.; Thielens, M.L.; Khakharia, P.M.; Goetheer, E.L.V.; Schaber, K.

    2014-01-01

    Recently, studies have appeared pointing out that aerosols can dominate the total amine emission from amine based PCCC pilot plant scale installations. For the design of countermeasure types (upstream or downstream of the PCCC installation), it is crucial to have an idea of the aerosol size distribu

  8. Amination of allylic alcohols in water at room temperature.

    Science.gov (United States)

    Nishikata, Takashi; Lipshutz, Bruce H

    2009-06-04

    The "trick" to carrying out regiocontrolled aminations of allylic alcohols in water as the only medium is use of a nanomicelle's interior as the organic reaction solvent. When HCO(2)Me is present, along with the proper base and source of catalytic Pd, allylic amines are cleanly formed at room temperature.

  9. Effects of dietary amines on the gut and its vasculature.

    Science.gov (United States)

    Broadley, Kenneth J; Akhtar Anwar, M; Herbert, Amy A; Fehler, Martina; Jones, Elen M; Davies, Wyn E; Kidd, Emma J; Ford, William R

    2009-06-01

    Trace amines, including tyramine and beta-phenylethylamine (beta-PEA), are constituents of many foods including chocolate, cheeses and wines and are generated by so-called 'friendly' bacteria such as Lactobacillus, Lactococcus and Enterococcus species, which are found in probiotics. We therefore examined whether these dietary amines could exert pharmacological effects on the gut and its vasculature. In the present study we examined the effects of tyramine and beta-PEA on the contractile activity of guinea-pig and rat ileum and upon the isolated mesenteric vasculature and other blood vessels. Traditionally, these amines are regarded as sympathomimetic amines, exerting effects through the release of noradrenaline from sympathetic nerve endings, which should relax the gut. A secondary aim was therefore to confirm this mechanism of action. However, contractile effects were observed in the gut and these were independent of noradrenaline, acetylcholine, histamine and serotonin receptors. They were therefore probably due to the recently described trace amine-associated receptors. These amines relaxed the mesenteric vasculature. In contrast, the aorta and coronary arteries were constricted, a response that was also independent of a sympathomimetic action. From these results, we propose that after ingestion, trace amines could stimulate the gut and improve intestinal blood flow. Restriction of blood flow elsewhere diverts blood to the gut to aid digestion. Thus, trace amines in the diet may promote the digestive process through stimulation of the gut and improved gastrointestinal circulation.

  10. Conditions allowing the formation of biogenic amines in cheese

    NARCIS (Netherlands)

    Joosten, H.M.L.J.

    1988-01-01

    A study was undertaken to reveal the conditions that allow the formation of biogenic amines in cheese.

    The starters most commonly used in the Dutch cheese industry do not have decarboxylative properties. Only if the milk or curd is contaminated with non-starter bacteria, amine

  11. Conditions allowing the formation of biogenic amines in cheese.

    NARCIS (Netherlands)

    Joosten, H.M.L.J.

    1988-01-01

    A study was undertaken to reveal the conditions that allow the formation of biogenic amines in cheese.The starters most commonly used in the Dutch cheese industry do not have decarboxylative properties. Only if the milk or curd is contaminated with non-starter bacteria, amine formation may be observ

  12. 40 CFR 721.643 - Ethoxylated alcohol, phosphated, amine salt.

    Science.gov (United States)

    2010-07-01

    ... salt. 721.643 Section 721.643 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.643 Ethoxylated alcohol, phosphated, amine salt. (a) Chemical substance... alcohol, phosphated, amine salt (PMN P-96-1478) is subject to reporting under this section for the...

  13. 40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylbenzene sulfonate, amine salt... Substances § 721.1625 Alkylbenzene sulfonate, amine salt. (a) Chemical substance and significant new uses... salt (PMN P-90-456) is subject to reporting under this section for the significant new use described in...

  14. Nitrosamine formation in amine scrubbing at desorber temperatures.

    Science.gov (United States)

    Fine, Nathan A; Goldman, Mark J; Rochelle, Gary T

    2014-01-01

    Amine scrubbing is a thermodynamically efficient and industrially proven method for carbon capture, but amine solvents can nitrosate in the desorber, forming potentially carcinogenic nitrosamines. The kinetics of reactions involving nitrite and monoethanolamine (MEA), diethanolamine (DEA), methylethanolamine (MMEA), and methyldiethanolamine (MDEA) were determined under desorber conditions. The nitrosations of MEA, DEA, and MMEA are first order in nitrite, carbamate species, and hydronium ion. Nitrosation of MDEA, a tertiary amine, is not catalyzed by the addition of CO2 since it cannot form a stable carbamate. Concentrated and CO2 loaded MEA was blended with low concentrations of N-(2-hydroxyethyl) glycine (HeGly), hydroxyethyl-ethylenediamine (HEEDA), and DEA, secondary amines common in MEA degradation. Nitrosamine yield was proportional to the concentration of secondary amine and was a function of CO2 loading and temperature. Blends of tertiary amines with piperazine (PZ) showed n-nitrosopiperazine (MNPZ) yields close to unity, validating the slow nitrosation rates hypothesized for tertiary amines. These results provide a useful tool for estimating nitrosamine accumulation over a range of amine solvents.

  15. Is copper chelation an effective anti-angiogenic strategy for cancer treatment?

    Science.gov (United States)

    Antoniades, V; Sioga, A; Dietrich, E M; Meditskou, S; Ekonomou, L; Antoniades, K

    2013-12-01

    Angiogenesis and the acquisition of an angiogenic phenotype is important for cancer cell proliferation. Copper in an essential trace element that participates in many enzymatic complexes like the cytochrome c, superoxide dismutase and lysyl oxidase and it is involved in processes, like embryogenesis, growth, angiogenesis and carcinogenesis. In particular, its involvement in carcinogenesis was described for the first time in oral submucous fibrosis, where fibroblasts produce large amounts of collagen in the presence of copper. Copper's action in carcinogenesis is two-fold: (1) it participates in reactions with an increased redox potential that result in the production of oxidative products and oxidative stress. Through this mechanism, copper may cause DNA mutations in the nucleus and mitochondria or alterations to membrane phospholipids, (2) it participates in angiogenesis even in the absence of angiogenic molecules, as it was reported for the first time in rabbit cornea models with copolymer pellets charged with PGE1. Copper chelation regimens like penicillamine and tetrathiomolybdate are being described in the literature as having anti-angiogenic, anti-fibrotic and anti-inflammatory actions. Animal models of brain cancer that evaluated the anti-angiogenic properties of copper, have proven evidence of the reduction of tumor's microvascular supply, tumor volume and vascular permeability after plasma copper levels reduction. Interestingly, plasma copper levels reduction was shown to suppress micrometastases generation in mice models of breast cancer. We hypothesize that copper chelation therapy: increases oxidative stress in cancer cells to a level that does not allow survival because of the reduction of anti-oxidative enzymes production. It may also result in inhibition of angiogenesis and of the initiation of the angiogenic switch, because copper normally enhances endothelial cell migration and proliferation, improves binding of growth factors to endothelial cells

  16. Fabricating Copper Nanotubes by Electrodeposition

    Science.gov (United States)

    Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel

    2009-01-01

    Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

  17. A general and efficient approach to 2H-indazoles and 1H-pyrazoles through copper-catalyzed intramolecular N-N bond formation under mild conditions.

    Science.gov (United States)

    Hu, Jiantao; Cheng, Yongfeng; Yang, Yiqing; Rao, Yu

    2011-09-28

    A new efficient copper-catalyzed intramolecular amination reaction has been developed to readily synthesise a wide variety of multi-substituted 2H-indazole and 1H-pyrazole derivatives from easily accessible starting materials under mild conditions. A highly selective ligand for estrogen receptor β was prepared in three steps by employing this method.

  18. A highly active and reusable copper(I)-tren catalyst for the "click" 1,3-dipolar cycloaddition of azides and alkynes.

    Science.gov (United States)

    Candelon, Nicolas; Lastécouères, Dominique; Diallo, Abdou Khadri; Aranzaes, Jaime Ruiz; Astruc, Didier; Vincent, Jean-Marc

    2008-02-14

    The copper(I) complex [Cu(C18(6)tren)]Br 1 (C18(6)tren = tris(2-dioctadecylaminoethyl)amine) which exhibits a good stability towards aerobic conditions is a versatile, highly reactive and recyclable catalyst for the Huisgen cycloaddition of azides with terminal or internal alkynes and is a useful catalyst for the preparation of "click" dendrimers.

  19. Copper-catalyzed aerobic C(sp2)-H functionalization for C-N bond formation: synthesis of pyrazoles and indazoles.

    Science.gov (United States)

    Li, Xianwei; He, Li; Chen, Huoji; Wu, Wanqing; Jiang, Huanfeng

    2013-04-19

    A simple, practical, and highly efficient synthesis of pyrazoles and indazoles via copper-catalyzed direct aerobic oxidative C(sp(2))-H amination has been reported herein. This process tolerated a variety of functional groups under mild conditions. Further diversification of pyrazoles was also investigated, which provided its potential for drug discovery.

  20. Conformational switching of ethano-bridged Cu,H2-bis-porphyrin induced by aromatic amines

    Directory of Open Access Journals (Sweden)

    Simona Bettini

    2015-11-01

    Full Text Available Cu,H2-bis-porphyrin (Cu,H2-Por2, in which copper porphyrin and free-base porphyrin are linked together by an ethano-bridge, was dissolved in chloroform and spread at the air/liquid subphase interface of a Langmuir trough. The bis-porphyrin derivative, floating film was characterized by reflection spectroscopy and the surface pressure of the floating film was studied as a function of the mean area per molecule. When aromatic amines are dissolved in the subphase, an evident interaction between the bis-porphyrin host and the aromatic amine guest is observed. A clear-cut variation of the profile of surface pressure vs area per molecule curve is observed. Reflection spectroscopy highlights that the aromatic amines dissolved in the subphase are able to induce the syn-to-anti conformational switching in the bis-porphyrin derivative. The Langmuir–Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase to a surface plasmon resonance (SPR substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM in aqueous solution. The high selectivity of the SPR sensing device has been verified by checking the spectral response of the active layer towards other analytes dissolved in the aqueous solutions.

  1. [Copper and the human body].

    Science.gov (United States)

    Krízek, M; Senft, V; Motán, J

    1997-11-19

    Copper is one of the essential trace elements. It is part of a number of enzymes. Deficiency of the element is manifested by impaired haematopoesis, bone metabolism, disorders of the digestive, cardiovascular and nervous system. Deficiency occurs in particular in patients suffering from malnutrition, malabsorption, great copper losses during administration of penicillamine. Sporadically copper intoxications are described (suicidal intentions or accidental ingestion of beverages with a high copper content). Acute exposure to copper containing dust is manifested by metal fume fever. Copper salts can produce local inflammations. Wilson's disease is associated with inborn impaired copper metabolism. In dialyzed patients possible contaminations of the dialyzate with copper must be foreseen as well as the possible release of copper from some dialyzation membranes. With the increasing amount of copper in the environment it is essential to monitor the contamination of the environment.

  2. NADPH oxidase: an enzyme for multicellularity?

    Science.gov (United States)

    Lalucque, Hervé; Silar, Philippe

    2003-01-01

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

  3. NADH/NADPH Oxidase and Vascular Function.

    Science.gov (United States)

    Griendling, K K; Ushio-Fukai, M

    1997-11-01

    The vascular NADH/NADPH oxidase has been shown to be the major source of superoxide in the vessel wall. Recent work has provided insight into its structure and activity in vascular cells. This enzyme is involved in both vascular smooth muscle hypertrophy and in some forms of impaired endothelium-dependent relaxation. Because oxidative stress in general participates in the pathogenesis of hypertension and atherosclerosis, the enzymes that produce reactive oxygen species may be important determinants of the course of vascular disease. (Trends Cardiovasc Med 1997;7:301-307). © 1997, Elsevier Science Inc.

  4. OXIDASE REACTION OF VARIOUS GROUPS OF BACTERIA.

    Science.gov (United States)

    Felton, L D

    1923-08-31

    1. A simple technique is described for studying the oxidase action of bacteria by means of the oxidation of p-aminoleucomalachite green. 2. It is shown that pneumococci under aerobic conditions produced an oxidase when grown on suitable medium. The sera of any of seven different animal species constitute such a medium, the degree of oxidation by the pneumococcus depending upon the animal from which the serum was taken-rat, guinea pig, rabbit, horse, man, cat, and chicken in order of diminishing suitability. 3. Conditions favoring the oxidation of p-aminoleucomalachite green by a single strain of pneumococci are: the presence of a slight amount of hemoglobin, dextrose, H ion concentration on the add side, and heating of fresh serum for 30 minutes at 56 degrees C. Conditions preventing the oxidation are: sterilized meat infusion, 1 per cent peptone, plain broth, a high concentration of hemoglobin, and absence of oxygen. In a quantitative fashion, meat infusion, 1 per cent peptone, and plain broth interfere with the suitability of serum as a substratum of oxidase production by the pneumococcus. 4. Twenty-three microbic species were studied with reference to oxidative power. They were grown upon 10 per cent horse serum, with and without dextrose, upon 10 per cent guinea pig serum, and upon plain broth. Only three of the twenty-three gave evidence of oxidative power as tested by p-aminoleucomalachite green; namely, the pneumococcus, Streptococcus viridans, and Streptococcus haemolyticus. Among the strains, of these three pneumococci gave the most intense reaction, after which Streptococcus viridans and Streptococcus haemolyticus follow in the order named, but with a noticeable variation among the different strains of Streptococcus haemolyticus. 5. Hemolytic streptococci of human and bovine origin were studied. The only variation in the type of reaction was manifested by the streptococci of milk and cheese origin. Strains from these sources showed definitely the least

  5. Factors influencing biogenic amines accumulation in dairy products

    Directory of Open Access Journals (Sweden)

    Daniel M. eLinares

    2012-05-01

    Full Text Available Fermented foods are within the food products more often complained of having caused biogenic amines poisoning. Concerning milk-based fermented foods, cheese is the main product likely to contain significant levels of biogenic amines, specially tyramine, histamine and putrescine. Prompted by the increasing awareness of the risks related to dietary uptake of high biogenic amine loads, in this review we report about cheese elaboration and processing technological aspects affecting biogenic amines levels. Synthesis of biogenic amines is possible only when three conditions converge: i availability of the substrate amino acids; ii presence of microorganisms with the appropriate catabolic pathway activated; and iii environmental conditions favorable to the decarboxilation activity. These conditions depend on several factors such as milk treatment (pasteurization, use of starter cultures, NaCl concentration, time and temperature of ripening and preservation, pH… which will be discussed in this chapter.

  6. Reaction of alkynes and azides: not triazoles through copper-acetylides but oxazoles through copper-nitrene intermediates.

    Science.gov (United States)

    Haldón, Estela; Besora, Maria; Cano, Israel; Cambeiro, Xacobe C; Pericàs, Miquel A; Maseras, Feliu; Nicasio, M Carmen; Pérez, Pedro J

    2014-03-17

    Well-defined copper(I) complexes of composition [Tpm*(,Br) Cu(NCMe)]BF4 (Tpm*(,Br) =tris(3,5-dimethyl-4-bromo-pyrazolyl)methane) or [Tpa(*) Cu]PF6 (Tpa(*) =tris(3,5-dimethyl-pyrazolylmethyl)amine) catalyze the formation of 2,5-disubstituted oxazoles from carbonyl azides and terminal alkynes in a direct manner. This process represents a novel procedure for the synthesis of this valuable heterocycle from readily available starting materials, leading exclusively to the 2,5-isomer, attesting to a completely regioselective transformation. Experimental evidence and computational studies have allowed the proposal of a reaction mechanism based on the initial formation of a copper-acyl nitrene species, in contrast to the well-known mechanism for the copper-catalyzed alkyne and azide cycloaddition reactions (CuAAC) that is triggered by the formation of a copper-acetylide complex. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Comprehensive set of integrative plasmid vectors for copper-inducible gene expression in Myxococcus xanthus.

    Science.gov (United States)

    Gómez-Santos, Nuria; Treuner-Lange, Anke; Moraleda-Muñoz, Aurelio; García-Bravo, Elena; García-Hernández, Raquel; Martínez-Cayuela, Marina; Pérez, Juana; Søgaard-Andersen, Lotte; Muñoz-Dorado, José

    2012-04-01

    Myxococcus xanthus is widely used as a model system for studying gliding motility, multicellular development, and cellular differentiation. Moreover, M. xanthus is a rich source of novel secondary metabolites. The analysis of these processes has been hampered by the limited set of tools for inducible gene expression. Here we report the construction of a set of plasmid vectors to allow copper-inducible gene expression in M. xanthus. Analysis of the effect of copper on strain DK1622 revealed that copper concentrations of up to 500 μM during growth and 60 μM during development do not affect physiological processes such as cell viability, motility, or aggregation into fruiting bodies. Of the copper-responsive promoters in M. xanthus reported so far, the multicopper oxidase cuoA promoter was used to construct expression vectors, because no basal expression is observed in the absence of copper and induction linearly depends on the copper concentration in the culture medium. Four different plasmid vectors have been constructed, with different marker selection genes and sites of integration in the M. xanthus chromosome. The vectors have been tested and gene expression quantified using the lacZ gene. Moreover, we demonstrate the functional complementation of the motility defect caused by lack of PilB by the copper-induced expression of the pilB gene. These versatile vectors are likely to deepen our understanding of the biology of M. xanthus and may also have biotechnological applications.

  8. Copper deficiency induced emphysema is associated with focal adhesion kinase inactivation.

    Directory of Open Access Journals (Sweden)

    Shiro Mizuno

    Full Text Available BACKGROUND: Copper is an important regulator of hypoxia inducible factor 1 alpha (HIF-1α dependent vascular endothelial growth factor (VEGF expression, and is also required for the activity of lysyl oxidase (LOX to effect matrix protein cross-linking. Cell detachment from the extracellular matrix can induce apoptosis (anoikis via inactivation of focal adhesion kinase (FAK. METHODOLOGY: To examine the molecular mechanisms whereby copper depletion causes the destruction of the normal alveolar architecture via anoikis, Male Sprague-Dawley rats were fed a copper deficient diet for 6 weeks while being treated with the copper chelator, tetrathiomolybdate. Other groups of rats were treated with the inhibitor of auto-phosphorylation of FAK, 1,2,4,5-benzenetetraamine tetrahydrochloride (1,2,4,5-BT or FAK small interfering RNA (siRNA. PRINCIPAL FINDINGS: Copper depletion caused emphysematous changes, decreased HIF-1α activity, and downregulated VEGF expression in the rat lungs. Cleaved caspase-3, caspase-8 and Bcl-2 interacting mediator of cell death (Bim expression was increased, and the phosphorylation of FAK was decreased in copper depleted rat lungs. Administration of 1,2,4,5-BT and FAK siRNA caused emphysematous lung destruction associated with increased expression of cleaved capase-3, caspase-8 and Bim. CONCLUSIONS: These data indicate that copper-dependent mechanisms contribute to the pathogenesis of emphysema, which may be associated with decreased HIF-1α and FAK activity in the lung.

  9. Chemical genetics suggests a critical role for lysyl oxidase in zebrafish notochord morphogenesis.

    Science.gov (United States)

    Anderson, Carrie; Bartlett, Stephen J; Gansner, John M; Wilson, Duncan; He, Ling; Gitlin, Jonathan D; Kelsh, Robert N; Dowden, James

    2007-01-01

    As a result of a chemical genetic screen for modulators of metalloprotease activity, we report that 2-mercaptopyridine-N-oxide induces a conspicuous undulating notochord defect in zebrafish embryos, a phenocopy of the leviathan mutant. The location of the chemically-induced wavy notochord correlated with the timing of application, thus defining a narrow chemical sensitivity window during segmentation stages. Microscopic observations revealed that notochord undulations appeared during the phase of notochord cell vacuolation and notochord elongation. Notochord cells become swollen as well as disorganized, while electron microscopy revealed disrupted organization of collagen fibrils in the surrounding sheath. We demonstrate by assay in zebrafish extracts that 2-mercaptopyridine-N-oxide inhibits lysyl oxidase. Thus, we provide insight into notochord morphogenesis and reveal novel compounds for lysyl oxidase inhibition. Taken together, these data underline the utility of small molecules for elucidating the dynamic mechanisms of early morphogenesis and provide a potential explanation for the recently established role of copper in zebrafish notochord formation.

  10. Targeting copper in cancer therapy: 'Copper That Cancer'.

    Science.gov (United States)

    Denoyer, Delphine; Masaldan, Shashank; La Fontaine, Sharon; Cater, Michael A

    2015-11-01

    Copper is an essential micronutrient involved in fundamental life processes that are conserved throughout all forms of life. The ability of copper to catalyze oxidation-reduction (redox) reactions, which can inadvertently lead to the production of reactive oxygen species (ROS), necessitates the tight homeostatic regulation of copper within the body. Many cancer types exhibit increased intratumoral copper and/or altered systemic copper distribution. The realization that copper serves as a limiting factor for multiple aspects of tumor progression, including growth, angiogenesis and metastasis, has prompted the development of copper-specific chelators as therapies to inhibit these processes. Another therapeutic approach utilizes specific ionophores that deliver copper to cells to increase intracellular copper levels. The therapeutic window between normal and cancerous cells when intracellular copper is forcibly increased, is the premise for the development of copper-ionophores endowed with anticancer properties. Also under investigation is the use of copper to replace platinum in coordination complexes currently used as mainstream chemotherapies. In comparison to platinum-based drugs, these promising copper coordination complexes may be more potent anticancer agents, with reduced toxicity toward normal cells and they may potentially circumvent the chemoresistance associated with recurrent platinum treatment. In addition, cancerous cells can adapt their copper homeostatic mechanisms to acquire resistance to conventional platinum-based drugs and certain copper coordination complexes can re-sensitize cancer cells to these drugs. This review will outline the biological importance of copper and copper homeostasis in mammalian cells, followed by a discussion of our current understanding of copper dysregulation in cancer, and the recent therapeutic advances using copper coordination complexes as anticancer agents.

  11. Amine Reactivity with Nanoclusters of Sulfuric Acid and Ammonia

    Science.gov (United States)

    Johnston, M. V.; Bzdek, B. R.; DePalma, J.

    2011-12-01

    Alkyl amines have emerged as key species in new particle formation and growth. This interest is reinforced by ambient measurements of amines (e.g. Smith et al., 2010) and enhanced levels of nitrogen (e.g. Bzdek et al., 2011) during growth of newly formed particles. An important mechanism of amine uptake is aminium salt formation, either by substituting for ammonium ions that already exist in the particle or by opening new channels for salt formation that are not favorable with ammonia. This presentation will focus on recent experimental and computational work in our group to study amine uptake into charged nanoclusters of sulfuric acid and ammonia. In the experimental work, clusters are produced by electrospray of an ammonium sulfate solution and then drawn into a Fourier transform ion cyclotron resonance mass spectrometer where a specific cluster is isolated and exposed to amine vapor. We find that amine reactivity is dependent on the size, composition and charge of the isolated cluster. For small clusters of either polarity, all ammonium ions reside on the surface and amine substitution occurs with near unit reaction probability. As the cluster size increases, an ammonium ion can be encapsulated in the center of the cluster, which provides a steric hindrance to amine substitution. Negatively charged clusters are more likely to be acidic than positively charged clusters. For acidic clusters, incoming amine molecules first substitute for preexisting ammonium ions and then add to the cluster until a "neutralized" aminium bisulfate composition is reached. Computational studies of these clusters provide fundamental insight into the thermodynamics and kinetics of amine uptake.

  12. Multicopper oxidase-1 orthologs from diverse insect species have ascorbate oxidase activity.

    Science.gov (United States)

    Peng, Zeyu; Dittmer, Neal T; Lang, Minglin; Brummett, Lisa M; Braun, Caroline L; Davis, Lawrence C; Kanost, Michael R; Gorman, Maureen J

    2015-04-01

    Members of the multicopper oxidase (MCO) family of enzymes can be classified by their substrate specificity; for example, ferroxidases oxidize ferrous iron, ascorbate oxidases oxidize ascorbate, and laccases oxidize aromatic substrates such as diphenols. Our previous work on an insect multicopper oxidase, MCO1, suggested that it may function as a ferroxidase. This hypothesis was based on three lines of evidence: RNAi-mediated knock down of Drosophila melanogaster MCO1 (DmMCO1) affects iron homeostasis, DmMCO1 has ferroxidase activity, and DmMCO1 has predicted iron binding residues. In our current study, we expanded our focus to include MCO1 from Anopheles gambiae, Tribolium castaneum, and Manduca sexta. We verified that MCO1 orthologs have similar expression profiles, and that the MCO1 protein is located on the basal surface of cells where it is positioned to oxidize substrates in the hemolymph. In addition, we determined that RNAi-mediated knock down of MCO1 in A. gambiae affects iron homeostasis. To further characterize the enzymatic activity of MCO1 orthologs, we purified recombinant MCO1 from all four insect species and performed kinetic analyses using ferrous iron, ascorbate and two diphenols as substrates. We found that all of the MCO1 orthologs are much better at oxidizing ascorbate than they are at oxidizing ferrous iron or diphenols. This result is surprising because ascorbate oxidases are thought to be specific to plants and fungi. An analysis of three predicted iron binding residues in DmMCO1 revealed that they are not required for ferroxidase or laccase activity, but two of the residues (His374 and Asp380) influence oxidation of ascorbate. These two residues are conserved in MCO1 orthologs from insects and crustaceans; therefore, they are likely to be important for MCO1 function. The results of this study suggest that MCO1 orthologs function as ascorbate oxidases and influence iron homeostasis through an unknown mechanism.

  13. Activation of peroxyl and molecular oxygen using bis-benzimidazole diamide copper (II) compounds

    Indian Academy of Sciences (India)

    Pavan Mathur

    2006-11-01

    New tetradentate bis-benzimidazole ligands have been synthesized and utilized to prepare copper (II) complexes. Some of these copper (II) complexes have been characterized structurally. The copper (II) in these complexes is found to possess varying geometries. A distorted octahedral geometry is found with a highly unsymmetrical bidentate nitrate group. An unusual polymeric one-dimensional structure is observed where copper (II) is in a distorted square pyramidal geometry with a monodentate nitrate ion, having long Cu-O bond, while a distorted triagonal bipyramidal geometry is found with two carbonyl O atoms and a Cl atom in the equatorial plane, and two benzimidazole imine N atoms occupy the axial position. These compounds are found to activate the cumylperoxyl group, and this has been utilized in the facile oxidation of aromatic alcohols to aldehydes, where they act as catalysts with large turnovers. The yields of the respective products vary from 32 to 65%. The role of molecular oxygen has been studied and an attempt has been made to identify the "active copper species”. Activation of molecular oxygen has also been observed and has been used for oxidative dealkylation of a hindered phenol, producing di-butyl quinones with yields of 20-25% and 10-12 fold catalytic turnover. Dihydroxybenzenes and substituted catechols are also readily oxidized to the corresponding quinones, in oxygen-saturated solvents. Yields of 84% have been observed with 34-fold catalyst turnover, with di--butylcatechol. The activity of these copper (II) - bis-benzmidazolediamide compounds is reminiscent of the functioning of copper centres in galactose oxidase, tyrosinase and catechol oxidase.

  14. Non-hepatic tumors change the activity of genes encoding copper trafficking proteins in the liver.

    Science.gov (United States)

    Babich, Polina S; Skvortsov, Alexey N; Rusconi, Paolo; Tsymbalenko, Nadezhda V; Mutanen, Marja; Puchkova, Ludmila V; Broggini, Massimo

    2013-07-01

    To assess the statistical relationship between tumor growth and copper metabolism, we performed a metaanalysis of studies in which patients with neoplasms were characterized according to any of the copper status indexes (atomic copper serum concentration, serum oxidase activity, ceruloplasmin protein content). Our metaanalysis shows that in the majority of cases (more than 3100 patients), tumor growth positively correlates with the copper status indexes. Nude athymic CD-1 nu/nu mice with subcutaneous tumors of human origin, C57Bl/6J mice with murine melanoma and Apc(Min) mice with spontaneously developing adenomas throughout the intestinal tract were studied to experimentally determine the relationship between tumor progression, liver copper metabolism, and copper status indexes. We showed that the copper status indexes increased significantly during tumor growth. In the liver tissue of tumor-bearing mice, ceruloplasmin gene expression, as well as the expression of genes related to ceruloplasmin metallation (CTR1 and ATP7B), increased significantly. Moreover, the presence of an mRNA splice variant encoding a form of ceruloplasmin anchored to the plasma membrane by glycosylphosphatidyl inositol, which is atypical for hepatocytes, was also detected. The ATP7A copper transporter gene, which is normally expressed in the liver only during embryonic copper metabolism, was also activated. Depletion of holo-ceruloplasmin resulted in retardation of human HCT116 colon carcinoma cell growth in nude mice and induced DNA fragmentation in tumor cells. In addition, the concentration of cytochrome c increased significantly in the cytosol, while decreasing in the mitochondria. We discuss a possible trans-effect of developing tumors on copper metabolism in the liver.

  15. Does Dietary Copper Supplementation enhance or diminish PCB126 Toxicity in Rodent Liver?

    Science.gov (United States)

    Lai, Ian K.; Klaren, William D.; Li, Miao; Wels, Brian; Simmons, Donald L.; Olivier, Alicia K.; Haschek, Wanda M.; Wang, Kai; Ludewig, Gabriele; Robertson, Larry W.

    2013-01-01

    Copper is essential for the function of the mitochondrial electron transport chain and several antioxidant proteins. However, in its free form copper can participate in Fenton-like reactions that produce reactive hydroxyl radicals. Aryl-hydrocarbon receptor (AhR) agonists, including the most potent polychlorinated biphenyl (PCB) congener, 3,3',4,4',5-pentachlorobiphenyl (PCB126), increase copper levels in rodent livers. This is accompanied by biochemical and toxic changes. To assess the involvement of copper in PCB toxicity, male Sprague Dawley rats were fed an AIN-93G diet with differing dietary copper levels: low (2 ppm), adequate (6 ppm), and high (10 ppm). After three weeks, rats from each group were given a single ip injection of corn oil (control), 1, or 5 μmol/kg body weight PCB126. Two weeks following injections, biochemical and morphological markers of hepatic toxicity, trace metal status, and hepatic gene expression of metalloproteins were evaluated. Increasing dietary copper was associated with elevated tissue levels of copper and ceruloplasmin. In the livers of PCB126-treated rats the hallmark signs of AhR activation were present, including increased cytochrome P-450 and lipid levels, and decreased glutathione. In addition a doubling of hepatic copper levels was seen and overall metals homeostasis was disturbed, resulting in decreased hepatic selenium, manganese, zinc and iron. Expression of key metalloproteins was either decreased (cytochrome c oxidase), unchanged (ceruloplasmin and CuZnSOD) or increased (tyrosinase, metallothionein 1 and 2) with exposure to PCB126. Increases in metallothionein may contribute/reflect the increased copper seen. Alterations in dietary copper did not amplify or abrogate the hepatic toxicity of PCB126. PCB126 toxicity, i.e. oxidative stress and steatosis, is clearly associated with disturbed metals homeostasis. Understanding the mechanisms of this disturbance may provide tools to prevent liver toxicity by other Ah

  16. Synthesis and characterization of bisimide amines and bisimide amine-cured epoxy resins

    Science.gov (United States)

    Scola, D. A.

    1983-01-01

    An attempt is made to develop tough, moisture resistant, high char yield epoxy resins by means of novel bisimide amine (BIA) hardener curing agents and a state-of-the-art epoxy resin system. The BIAs are isolated as mixtures containing monomer, oligomer, and polymeric species, and then characterized by elemental analysis and high pressure liquid chromatography. The bisimide amine-cured epoxies (IMEs) were characterized with respect to moisture absorption, thermal properties, and physical and mechanical properties, as well as in the role of matrices in Celion 6000/IME composites. The relative toughness characteristics of each IME formulation was measured by the 10 deg off-axis tensile test, measuring the uniaxial tensile strength, shear strength, and shear-strain-to-failure of the composite systems.

  17. Magnetic Interactions in the Copper Complex (L-Aspartato)(1,10-phenanthroline)copper(II) Hydrate. An Exchange-Coupled Extended System with Two Dissimilar Copper Ions.

    Science.gov (United States)

    Brondino, Carlos D.; Calvo, Rafael; Atria, Ana María; Spodine, Evgenia; Nascimento, Otaciro R.; Peña, Octavio

    1997-07-02

    We report EPR measurements in single-crystal samples at the microwave frequencies 9.8 and 34.3 GHz and magnetic susceptibility measurements in polycrystalline samples for the ternary complex of copper with aspartic acid and phenanthroline, (L-aspartato)(1,10-phenanthroline)copper(II) hydrate. The crystal lattice of this compound is composed of two dissimilar copper ions identified as Cu(A) and Cu(B), which are in two types of copper chains called A and B, respectively, running parallel to the b crystal axis. The copper ions in the A chains are connected by the aspartic acid molecule, and those in the B chains by a chemical path that involves a carboxylate bridge and a hydrogen bond. Both chains are held together by a complex network of hydrogen bonds and by hydrophobic interactions between aromatic amines. Magnetic susceptibility data indicate a Curie-Weiss behavior in the studied temperature range (2-300 K). The EPR spectra at 9.8 GHz display a single exchange collapsed resonance for any magnetic field orientation, in the so-called strong exchange regime. Those at 34.3 GHz are within the so-called weak exchange regime and display two resonances which belong to each type of copper ion chain. The decoupling of the spectra at 34.3 GHz using a theory based on Anderson's model for the case of two weakly exchange coupled spins S = (1)/(2) allows one to obtain the angular variation of the squares of the g-factor and the peak-to-peak line width of each resonance. This model also allows one to evaluate the exchange parameter |J(AB)/k| = 2.7(6) mK associated with the chemical path connecting dissimilar copper ions. The line width data obtained for each component of the spectra at 34.3 GHz are analyzed in terms of a model based on Kubo and Tomita's theory, to obtain the exchange parameters |J(A)/k| = 0.77(2) K and |J(B)/k| = 1.44(2) K associated with the chemical paths connecting the similar copper ions of types A and B, respectively.

  18. Enzymatic Characterization and In Vivo Function of Five Terminal Oxidases in Pseudomonas aeruginosa

    OpenAIRE

    Arai, Hiroyuki; Kawakami, Takuro; Osamura, Tatsuya; Hirai, Takehiro; Sakai, Yoshiaki; Ishii, Masaharu

    2014-01-01

    The ubiquitous opportunistic pathogen Pseudomonas aeruginosa has five aerobic terminal oxidases: bo3-type quinol oxidase (Cyo), cyanide-insensitive oxidase (CIO), aa3-type cytochrome c oxidase (aa3), and two cbb3-type cytochrome c oxidases (cbb3-1 and cbb3-2). These terminal oxidases are differentially regulated under various growth conditions and are thought to contribute to the survival of this microorganism in a wide variety of environmental niches. Here, we constructed multiple mutant str...

  19. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  20. Electrochemical characterization of aminated acrylic conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Norma Mohammad [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia); Heng, Lee Yook [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia); Southeast Asia Disaster Prevention Research Initiative, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia); Ling, Tan Ling [Southeast Asia Disaster Prevention Research Initiative, Lestari Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor Darul Ehsan (Malaysia)

    2015-09-25

    New attempt has been made to synthesize aminated acrylic conducting polymer (AACP) using precursor of phenylvinylsulfoxide (PVS). The process was conducted via the integration of microemulsion and photopolymerization techniques. It has been utilized for covalent immobilization of amino groups by the adding of N-achryiloxisuccinimide (NAS). Thermal eliminating of benzene sulfenic acids from PVS has been done at 250 °C to form electroactive polyacetylene (PA) segment. Characterization of AACP has been conducted using fourier transform infrared (FTIR), scanning electron microscopy (SEM) and linear sweep cyclic voltammetry (CV). A range of 0.3-1.25μm particle size obtained from SEM characterization. A quasi-reversible system performed as shown in electrochemical study.

  1. Whole cell biotransformation for reductive amination reactions

    Science.gov (United States)

    Klatte, Stephanie; Lorenz, Elisabeth; Wendisch, Volker F

    2014-01-01

    Whole cell biotransformation systems with enzyme cascading increasingly find application in biocatalysis to complement or replace established chemical synthetic routes for production of, e.g., fine chemicals. Recently, we established an Escherichia coli whole cell biotransformation system for reductive amination by coupling a transaminase and an amino acid dehydrogenase with glucose catabolism for cofactor recycling. Transformation of 2-keto-3-methylvalerate to l-isoleucine by E. coli cells was improved by genetic engineering of glucose metabolism for improved cofactor regeneration. Here, we compare this system with different strategies for cofactor regeneration such as cascading with alcohol dehydrogenases, with alternative production hosts such as Pseudomonas species or Corynebacterium glutamicum, and with improving whole cell biotransformation systems by metabolic engineering of NADPH regeneration. PMID:24406456

  2. N-(3-Methylphenylquinoxalin-2-amine monohydrate

    Directory of Open Access Journals (Sweden)

    Azila Idris

    2010-09-01

    Full Text Available The quinoxaline system in the title hydrate, C15H13N3·H2O, is roughly planar, the r.m.s. deviation for the 18 non-H atoms being 0.188 Å; this conformation features a short intramolecular C—H...N(pyrazine interaction. In the crystal, the amine H atom forms an N—H...O hydrogen bond to the water molecule, which in turn forms two O—H...N hydrogen bonds to the pyrazine N atoms of different organic molecules. These interactions lead to supramolecular arrays in the bc plane that are two molecules thick; additional π–π interactions stabilize the layers [ring centroid–centroid distance = 3.5923 (7 Å]. The layers stack along the a-axis direction via C—H...π contacts.

  3. Amine scrubbing for CO2 capture.

    Science.gov (United States)

    Rochelle, Gary T

    2009-09-25

    Amine scrubbing has been used to separate carbon dioxide (CO2) from natural gas and hydrogen since 1930. It is a robust technology and is ready to be tested and used on a larger scale for CO2 capture from coal-fired power plants. The minimum work requirement to separate CO2 from coal-fired flue gas and compress CO2 to 150 bar is 0.11 megawatt-hours per metric ton of CO2. Process and solvent improvements should reduce the energy consumption to 0.2 megawatt-hour per ton of CO2. Other advanced technologies will not provide energy-efficient or timely solutions to CO2 emission from conventional coal-fired power plants.

  4. Synthesis of Boron-Containing Primary Amines

    Directory of Open Access Journals (Sweden)

    Sheng-Hsuan Chung

    2013-10-01

    Full Text Available In this study, boron-containing primary amines were synthesized for use as building blocks in the study of peptoids. In the first step, Gabriel synthesis conditions were modified to enable the construction of seven different aminomethylphenyl boronate esters in good to excellent yields. These compounds were further utilized to build peptoid analogs via an Ugi four-component reaction (Ugi-4CR under microwave irradiation. The prepared Ugi-4CR boronate esters were then successfully converted to the corresponding boronic acids. Finally, the peptoid structures were successfully modified by cross-coupling to aryl/heteroaryl chlorides via a palladium-mediated Suzuki coupling reaction to yield the corresponding derivatives in moderate to good yields.

  5. Characterization of the Cytochrome C Oxidase Assembly Factor Cox19 of 'Saccharomyces Cerevisiae'

    Energy Technology Data Exchange (ETDEWEB)

    Rigby, K.; Zhang, L.; Cobine, P.A.; George, G.N.; Winge, D.R.; /Utah U. /Saskatchewan U.

    2007-07-12

    Cox19 is an important accessory protein in the assembly of cytochrome c oxidase in yeast. The protein is functional when tethered to the mitochondrial inner membrane, suggesting its functional role within the intermembrane space. Cox19 resembles Cox17 in having a twin CX{sub 9}C sequence motif that adopts a helical hairpin in Cox17. The function of Cox17 appears to be a Cu(I) donor protein in the assembly of the copper centers in cytochrome c oxidase. Cox19 also resembles Cox17 in its ability to coordinate Cu(I). Recombinant Cox19 binds 1 mol eq of Cu(I) per monomer and exists as a dimeric protein. Cox19 isolated from the mitochondrial intermembrane space contains variable quantities of copper, suggesting that Cu(I) binding may be a transient property. Cysteinyl residues important for Cu(I) binding are also shown to be important for the in vivo function of Cox19. Thus, a correlation exists in the ability to bind Cu(I) and in vivo function.

  6. Laboratory-evolved vanillyl-alcohol oxidase produces natural vanillin

    NARCIS (Netherlands)

    Heuvel, van den R.H.H.; Berg, van den W.A.M.; Rovida, S.; Berkel, van W.J.H.

    2004-01-01

    The flavoenzyme vanillyl-alcohol oxidase was subjected to random mutagenesis to generate mutants with enhanced reactivity to creosol (2-methoxy-4-methylphenol). The vanillyl-alcohol oxidase-mediated conversion of creosol proceeds via a two-step process in which the initially formed vanillyl alcohol

  7. Endothelins and NADPH oxidases in the cardiovascular system.

    Science.gov (United States)

    Dammanahalli, Karigowda J; Sun, Zhongjie

    2008-01-01

    1. The endothelin (ET) system and NADPH oxidase play important roles in the regulation of cardiovascular function, as well as in the pathogenesis of hypertension and other cardiovascular diseases. 2. Endothelins activate NADPH oxidases and thereby increase superoxide production, resulting in oxidative stress and cardiovascular dysfunction. Thus, NADPH oxidases may mediate the role of endothelins in some cardiovascular diseases. However, the role of reactive oxygen species (ROS) in mediating ET-induced vasoconstriction and cardiovascular disease remains under debate, as evidenced by conflicting reports from different research teams. Conversely, activation of NADPH oxidase can stimulate ET secretion via ROS generation, which further enhances the cardiovascular effects of NADPH oxidase. However, little is known about how ROS activate the endothelin system. It seems that the relationship between ET-1 and ROS may vary with cardiovascular disorders. 3. Endothelins activate NADPH oxidase via the ET receptor-proline-rich tyrosine kinase-2 (Pyk2)-Rac1 pathway. Rac1 is an important regulator of NADPH oxidase. There is ample evidence supporting direct stimulation by Rac1 of NADPH oxidase activity. In addition, Rac1-induced cardiomyocyte hypertrophy is mediated by the generation of ROS.

  8. Priming and activation of NADPH oxidases in plants and animals.

    Science.gov (United States)

    Canton, Johnathan; Grinstein, Sergio

    2014-09-01

    In mammals, engagement of Toll-like receptors by microbe-associated molecular patterns enhances the responsiveness of NADPH oxidases. Two recent papers report a similar 'priming' mechanism for the plant oxidase RbohD. Despite lacking structural homology, the functional parallels between plants and animals reveal that a common regulatory logic arose by convergent evolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G

    2014-01-01

    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...

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

    Science.gov (United States)

    Feldman, J M; Chapman, B

    1975-12-01

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

  11. Enlightening the Mechanism of Copper Mediated PhotoRDRP via High-Resolution Mass Spectrometry.

    Science.gov (United States)

    Frick, Elena; Anastasaki, Athina; Haddleton, David M; Barner-Kowollik, Christopher

    2015-06-03

    The initiation mechanism of photochemically mediated Cu-based reversible-deactivation radical polymerization (photoRDRP) was investigated using pulsed-laser polymerization (PLP) and high-resolution mass spectrometry. The variation of the catalyst composition and ESI-MS analysis of the resulting products provided information on how initiator, ligand, copper species, and monomer are interacting upon irradiation with UV light. A discussion of the results allows for a new postulation of the mechanism of photoRDRP and-for the first time-the unambiguous identification of the initiating species and their interactions within the reaction mixture. One pathway for radical generation proceeds via UV light-induced C-Br bond scission of the initiator, giving rise to propagating radicals. The generation of copper(I) species from copper(II) can occur via several pathways, including, among others, via reduction by free amine ligand in its excited as well as from its ground state via the irradiation with UV light. The amine ligand serves as a strong reducing agent and is likely the main participant in the generation of copper(I) species.

  12. Modulation of NADPH oxidase activity by known uraemic retention solutes

    DEFF Research Database (Denmark)

    Schulz, Anna Marta; Terne, Cindy; Jankowski, Vera

    2014-01-01

    as the strongest inhibitor of NADPH oxidase (90% of DPI inhibition). Surprisingly, none of the uraemic retention solutes we investigated was found to increase NADPH oxidase activity. Furthermore, plasma from patients with CKD-5D before dialysis caused significantly higher inhibitory effect on NADPH oxidase...... inhibitory effect on NADPH oxidase activity in the presence of plasma from patients with CKD-5D after dialysis compared with before dialysis, we investigated the effect of 48 known and commercially available uraemic retention solutes on the enzymatic activity of NADPH oxidase. METHODS: Mononuclear leucocytes...... isolated from buffy coats of healthy volunteers were isolated, lysed and incubated with NADH in the presence of plasma from healthy controls and patients with CKD-5D. Furthermore, the leucocytes were lysed and incubated in the presence of uraemic retention solute of interest and diphenyleneiodonium...

  13. The NADH oxidase-Prx system in Amphibacillus xylanus.

    Science.gov (United States)

    Niimura, Youichi

    2007-01-01

    Amphibacillus NADH oxidase belongs to a growing new family of peroxiredoxin-linked oxidoreductases including alkyl hydroperoxide reductase F (AhpF). Like AhpF it displays extremely high hydroperoxide reductase activity in the presence of a Prx, thus making up the NADH oxidase-Prx system. The NADH oxidase primarily catalyzes the reduction of oxygen by NADH to form H2O2, while the Prx immediately reduces H2O2 (or ROOH) to water (or ROH). Consequently, the NADH oxidase-Prx system catalyzes the reduction of both oxygen and hydrogen peroxide to water with NADH as the preferred electron donor. The NADH oxidase-Prx system is widely distributed in aerobically growing bacteria lacking a respiratory chain and catalase, and plays an important role not only in scavenging hydroperoxides but also in regenerating NAD in these bacteria.

  14. Pea Seedling Histaminase as a Novel Therapeutic Approach to Anaphylactic and Inflammatory Disorders

    Directory of Open Access Journals (Sweden)

    Emanuela Masini

    2007-01-01

    Full Text Available Amine oxidases (AOs are ubiquitous enzymes involved in the metabolism of biogenic amines. Copper AOs (Cu-AOs catalyze the oxidative deamination of primary amine groups of several biogenic amines, such as putrescine, cadaverine, and histamine. In the present review, the effects of a plant amine oxidase (Cu-AO, histaminase, EC1.4.3.6 purified from pea seedlings in the modulation of IgE-mediated allergic reactions, and in the prevention of cardiac and splachnic postischemic reperfusion damage are reported.

  15. Biogenic amines in Portuguese traditional foods and wines.

    Science.gov (United States)

    Ferreira, Isabel M P L V O; Pinho, Olívia

    2006-09-01

    The presence of biogenic amines in foodstuffs is an important food safety problem because of the implication of these compounds in food intolerance and intoxication. The separation and quantification of biogenic amines in foods is normally performed by chromatographic techniques. This review contains descriptions of the quantification of biogenic amines in Portuguese traditional fermented and/or ripened foods and wines, including Protected Denomination of Origin cheeses, dry-cured sausages, and Portuguese wines (including Port wines), using different analytical methods based on high-pressure liquid chromatography (UV or diode array and/or fluorometric detectors) and gas chromatography (with a mass spectrometry detector). The evolution of biogenic amines during fermentation, ripening, aging, or storage of those products was also evaluated. Biogenic amine concentrations ranged widely within individual food items, and storage, transport, and handling conditions can influence to some extent the biogenic amines present and their concentrations. Traditional foods are an important part of the Portuguese diet, and a high intake of harmful amounts of biogenic amines from traditional Portuguese fermented foods is possible. However, extensive research is needed to extend the current limited database.

  16. Biogenic amine production by lactic acid bacteria isolated from cider.

    Science.gov (United States)

    Garai, G; Dueñas, M T; Irastorza, A; Moreno-Arribas, M V

    2007-11-01

    To study the occurrence of histidine, tyrosine and ornithine decarboxylase activity in lactic acid bacteria (LAB) isolated from natural ciders and to examine their potential to produce detrimental levels of biogenic amines. The presence of biogenic amines in a decarboxylase synthetic broth and in cider was determined by reversed-phase high-performance liquid chromatography (RP-HPLC). Among the 54 LAB strains tested, six (five lactobacilli and one oenococci) were biogenic amine producers in both media. Histamine and tyramine were the amines formed by the LAB strains investigated. Lactobacillus diolivorans were the most intensive histamine producers. This species together with Lactobacillus collinoides and Oenococcus oeni also seemed to produce tyramine. No ability to form histamine, tyramine or putrescine by Pediococus parvulus was observed, although it is a known biogenic amine producer in wines and beers. This study demonstrated that LAB microbiota growing in ciders had the ability to produce biogenic amines, particularly histamine and tyramine, and suggests that this capability might be strain-dependent rather than being related to a particular bacterial species. Production of biogenic amines by food micro-organisms has continued to be the focus of intensive study because of their potential toxicity. The main goal was to identify the microbial species capable of producing these compounds in order to control their presence and metabolic activity in foods.

  17. Water-soluble primary amine compounds in rural continental precipitation

    Science.gov (United States)

    Gorzelska, Krystyna; Galloway, James N.; Watterson, Karen; Keene, William C.

    Procedures for collecting, storing and analysing precipitation samples for organic nitrogen studies were developed. These procedures preserve chemical integrities of the species of interest, allow for up to 3 months storage and quantitative determination of water-soluble primary amine compounds, with the overall error at the 2 nM detection limit of less than 30%. This methodology was applied to study amino compounds in precipitation samples collected over a period of one year in central Virginia. Nitrogen concentrations of 13 amino acids and 3 aliphatic amines were summed to calculate the total amine nitrogen (TAN). The concentration of TAN ranged from below our detection level to 6658 nM, and possibly reflected a seasonal variation in the source strength of the atmospheric amines. Overall, the most commonly occurring amino compounds were methyl amine, ethyl amine, glutamic acid, glycine and serine. On average, the highest overall contribution to the TAN came from arginine, asparagine, glutamine, methyl amine, serine and alanine. However, large qualitative and quantitative variations observed among samples warrant caution in interpretation and application of the averaged values. TAN in Charlottesville precipitation contributed from less than 1 to ca 10% of the ammonium nitrogen level. However, our estimates show that amino compounds may contribute significantly to reduced nitrogen budget in precipitation in remote regions.

  18. Cloning and characterization of a new laccase from Lactobacillus plantarum J16 CECT 8944 catalyzing biogenic amines degradation.

    Science.gov (United States)

    Callejón, S; Sendra, R; Ferrer, S; Pardo, I

    2016-04-01

    In our search for degrading activities of biogenic amines (BAs) in lactic acid bacteria, a protein annotated as laccase enzyme was identified in Lactobacillus plantarum J16 (CECT 8944). In this study, the gene of this new laccase was cloned and heterologously overexpressed in Escherichia coli. The recombinant laccase protein was purified and characterized biochemically. The purified laccase showed characteristic spectroscopic properties of blue multicopper oxidases. The enzyme has a molecular weight of ∼ 62.5 kDa and activity toward typical laccase substrates 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,6-dimethoxyphenol (2,6-DMP). The pH optima on ABTS and 2,6-DMP were 3.5 and 7.0, respectively. Kinetic constants Km and Vmax were of 0.21 mM and 0.54 U/mg for ABTS and 1.67 mM and 0.095 U/mg for 2,6-DMP, respectively. The highest oxidizing activity toward 2,6-DMP was obtained at 60 °C. However, after a preincubation step at 85 °C for 10 min, no residual activity was detected. It has been demonstrated that recombinant L. plantarum laccase oxidizes biogenic amines, mainly tyramine, and thus presents new biotechnological potential for the enzyme in eliminating toxic compounds present in fermented food and beverages.

  19. Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

  20. BIOGENIC AMINES CONTENT IN SELECTED WINES DURING WINEMAKING

    Directory of Open Access Journals (Sweden)

    Radka Flasarová

    2012-02-01

    Full Text Available The aim of this study was to describe the development of selected biogenic amines (histamine; tyramine; phenylethylamine; putrescine; agmatine; and cadaverine during the winemaking in 10 selected species grown in Central Europe in 2008. The analysis was performed using ion-exchange chromatography by the sodium-citrate buffers with the post-column ninhydrin derivatization and photometric detection. A comparison of the content of biogenic amines in red and wine varieties showed that red wines have higher concentrations of biogenic amines.

  1. Investigating the effects of metals on phenol oxidase-producing nitrogen-fixing Azotobacter chroococcum.

    Science.gov (United States)

    Herter, Susanne; Schmidt, Marlen; Thompson, Mark L; Mikolasch, Annett; Schauer, Frieder

    2013-06-01

    Expression of phenol oxidases (PO) in bacteria is often observed during physiological and morphological changes; in the nitrogen-fixing strain Azotobacter chroococcum SBUG 1484, it is accompanied by the formation of encysted cells and melanin. Herein, we studied the effects of copper and the depletion of the nitrogenase-relevant metals molybdenum and iron on physiological characteristics such as culture pigmentation, release of ortho-dihydroxylated melanin precursors, and expression of PO activity in A. chroococcum. Biomass production and melanogenic appearance were directly affected by the depletion of either iron or molybdenum, or in the absence of both metals. Only nitrogen-fixing cells growing in the presence of both metals and cultures supplemented with iron (molybdenum starved) showed the ability to produce an intensively brown-black melanin pigment typically associated with A. chroococcum. Accordingly, PO production was only detected in the presence of both metals and in iron-supplemented cultures starved of molybdenum. The total amount of catecholate siderophores produced by nitrogen-fixing melanogenic cells was considerably higher than in cultures starved of metal ions. Induction of enhanced PO activity was stimulated by additional copper sulfate, possibly related to cellular processes involved in the detoxification of this particular metal, and revealed distinct release of the ortho-dihydroxylated melanin precursors catechol and 3,4-dihydroxybenzoic acid.

  2. Mutations in COA6 cause cytochrome c oxidase deficiency and neonatal hypertrophic cardiomyopathy.

    Science.gov (United States)

    Baertling, Fabian; A M van den Brand, Mariel; Hertecant, Jozef L; Al-Shamsi, Aisha; P van den Heuvel, Lambert; Distelmaier, Felix; Mayatepek, Ertan; Smeitink, Jan A; Nijtmans, Leo G J; Rodenburg, Richard J T

    2015-01-01

    COA6/C1ORF31 is involved in cytochrome c oxidase (complex IV) biogenesis. We present a new pathogenic COA6 variant detected in a patient with neonatal hypertrophic cardiomyopathy and isolated complex IV deficiency. For the first time, clinical details about a COA6-deficient patient are given and patient fibroblasts are functionally characterized: COA6 protein is undetectable and steady-state levels of complex IV and several of its subunits are reduced. The monomeric COX1 assembly intermediate accumulates. Using pulse-chase experiments, we demonstrate an increased turnover of mitochondrial encoded complex IV subunits. Although monomeric complex IV is decreased in patient fibroblasts, the CI/CIII2 /CIVn -supercomplexes remain unaffected. Copper supplementation shows a partial rescue of complex IV deficiency in patient fibroblasts. We conclude that COA6 is required for complex IV subunit stability. Furthermore, the proposed role in the copper delivery pathway to complex IV subunits is substantiated and a therapeutic lead for COA6-deficient patients is provided.

  3. Formation of high nuclearity mixed-valent polyoxovanadates in the presence of copper amine complexes

    Indian Academy of Sciences (India)

    Jency Thomas; Sanjeev Sharma; S E Lofland; K V Ramanujachary; A Ramanana

    2006-01-01

    Two new Müller-type clusters, a one-dimensional solid {Cu()2}4[Cl ⊂ V15O36]$\\cdot$12H2O 1, and a three-dimensional solid {Cu()2}4[Cl ⊂ V18O42]$\\cdot$12H2O 2, have been synthesised by employing identical hydrothermal conditions except varying the nature of organic diamine. 1 crystallised in a chiral space group 212121 with = 12.757(1), = 18.927(2) and = 28.590(3) Å, and = 4. 2 crystallised in a tetragonal system with space group 4/, = 15.113(1) and = 18.542(3) Å, and = 2. Mixed-valent vanadium ions in structures 1 and 2 have been established both by magnetisation and bond-length bondvalence measurements. Chemistry of formation of high nuclearity polyoxovanadate clusters is discussed.

  4. Electrochemically Protected Copper(I)-Catalyzed Azide-Alkyne Cycloaddition

    Science.gov (United States)

    Hong, Vu; Udit, Andrew K.; Evans, Richard A.; Finn, M.G.

    2012-01-01

    The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has found broad application in myriad fields. For the most demanding applications requiring high yields at low substrate concentrations, highly active but air-sensitive copper complexes must be used. We describe here the use of an electrochemical potential to maintain catalysts in the active Cu(I) oxidation state in the presence of air. The simple procedure efficiently achieves excellent yields of CuAAC products involving both small molecule and protein substrates without the use of potentially damaging chemical reducing agents. A new water-soluble carboxylated version of the popular tris(benzyltriazolylmethyl)amine (TBTA) ligand is described. Cyclic voltammetry revealed reversible or quasi-reversible electrochemical redox behavior of copper complexes of the TBTA derivative (2; E1/2 = 60 mV vs. Ag/AgCl), sulfonated bathophenanthroline (3; E1/2 = -60 mV), and sulfonated tris(benzimidazoylmethyl)amine (4; E1/2 ~ -70 mV), and showed catalytic turnover to be rapid relative to the voltammetry time scale. Under the influence of a -200 mV potential established using a reticulated vitreous carbon working electrode, CuSO4 and 3 formed a superior catalyst. Electrochemically-protected bioconjugations in air were performed using bacteriophage Qβ derivatized with azide moieties at surface lysine residues. The complete addressing of more than 600 reactive sites per particle was demonstrated within 12 hours of electrolysis with sub-stoichiometric quantities of Cu•3. PMID:18504727

  5. Electrochemically protected copper(I)-catalyzed azide-alkyne cycloaddition.

    Science.gov (United States)

    Hong, Vu; Udit, Andrew K; Evans, Richard A; Finn, M G

    2008-06-16

    The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has found broad application in myriad fields. For the most demanding applications that require high yields at low substrate concentrations, highly active but air-sensitive copper complexes must be used. We describe here the use of an electrochemical potential to maintain catalysts in the active Cu(I) oxidation state in the presence of air. This simple procedure efficiently achieves excellent yields of CuAAC products from both small-molecule and protein substrates without the use of potentially damaging chemical reducing agents. A new water-soluble carboxylated version of the popular tris(benzyltriazolylmethyl)amine (TBTA) ligand is also described. Cyclic voltammetry revealed reversible or quasi-reversible electrochemical redox behavior of copper complexes of the TBTA derivative (2; E(1/2)=60 mV vs. Ag/AgCl), sulfonated bathophenanthroline (3; E(1/2)=-60 mV), and sulfonated tris(benzimidazoylmethyl)amine (4; E(1/2) approximately -70 mV), and showed catalytic turnover to be rapid relative to the voltammetry time scale. Under the influence of a -200 mV potential that was established by using a reticulated vitreous carbon working electrode, CuSO4 and 3 formed a superior catalyst. Electrochemically protected bioconjugations in air were performed by using bacteriophage Qbeta that was derivatized with azide moieties at surface lysine residues. Complete derivatization of more than 600 reactive sites per particle was demonstrated within 12 h of electrolysis with substoichiometric quantities of Cu3.

  6. Comparison of Solvation Effects on CO2 Capture with Aqueous Amine Solutions and Amine-Functionalized Ionic Liquids.

    Science.gov (United States)

    Yamada, Hidetaka

    2016-10-13

    Amines are the most widely utilized chemicals for postcombustion CO2 capture, because the reversible reactions between amines and CO2 through their moderate interaction allow effective "catch and release". Usually, CO2 is dissolved in the form of an anion such as carbamate or bicarbonate. Therefore, the reaction energy diagram is potentially governed to a large extent by the polarity of the surrounding solvent. Herein, we compared aqueous amine solutions and amine-functionalized ionic liquids by investigating their dielectric constants and performing an intrinsic reaction coordinate analysis of the CO2 absorption process. Quantum mechanical calculations at the CCSD(T)/6-311++G(d,p)//B3LYP/6-311++G(d,p) level within the continuum solvation model (SMD/IEF-PCM) revealed contrasting dependencies of C-N bond formation on the dielectric constant in those solutions. Amines react with CO2 on an energy surface that is significantly affected by the dielectric constant in conventional aqueous amine solutions, whereas amine-functionalized anions and CO2 form stable C-N bonds with a comparatively lower activation energy regardless of the dielectric constant.

  7. Preparation of Fe3O4@Au nano-composites by self-assembly technique for immobilization of glucose oxidase

    Institute of Scientific and Technical Information of China (English)

    WANG XianXiang; HUANG Shuo; Shan Zhi; YANG WanSheni

    2009-01-01

    Superparamagnetism amination nanocrystals Fe3O4 with 3-aminopropyltriethyloxy silane (APTES) were prepared by modified co-precipitation method. Next, 4-5 nm gold nanoparticles, prepared by classical Frens procedure, were coated on the surface of the amination Fe3O4 by self-assembly technology. The prepared Fe3O4@Au nanocomposite particles were investigated by transmission electron microscopy (TEM), UV-vis, infrared spectrum (FT-IR), and vibrating sample magnetometer (VSM) in order to eluci-date the morphology, optics and magnetic properties of the nanocomposites. Their uniform distribution of particle size, which is about 15 nm, and good magnetic responsiveness were observed. In view of the fact that Fe3O4 owns superparamagnetism and that nano-gold can readily combine with biological molecules, glucose oxidase (GOx) was chosen as a model to penetrate the condition of immobilizing enzyme, and enzymatic properties of resultant immobilized enzyme were studied as well. By systematic optimization, we established that at 28℃, and pH (5.5) and when mole ratio of Fe3O4:HAuCl4 was 0.5:1, the immobilization provided the best results. Finally, we are glad to find that the immobilized enzyme exhibits excellent thermostability in addition to its better stability than free enzyme. Thus, herein de-scribed immobilized enzyme could be used repeatedly with the assistance of an external magnetic field.

  8. NADPH Oxidases in Chronic Liver Diseases

    Directory of Open Access Journals (Sweden)

    Joy X. Jiang

    2014-01-01

    Full Text Available Oxidative stress is a common feature observed in a wide spectrum of chronic liver diseases including viral hepatitis, alcoholic, and nonalcoholic steatohepatitis. The nicotinamide adenine dinucleotide phosphate (NADPH oxidases (NOXs are emerging as major sources of reactive oxygen species (ROS. Several major isoforms are expressed in the liver, including NOX1, NOX2, and NOX4. While the phagocytic NOX2 has been known to play an important role in Kupffer cell and neutrophil phagocytic activity and inflammation, the nonphagocytic NOX homologues are increasingly recognized as key enzymes in oxidative injury and wound healing. In this review, we will summarize the current advances in knowledge on the regulatory pathways of NOX activation, their cellular distribution, and their role in the modulation of redox signaling in liver diseases.

  9. Glucose oxidase immobilization onto carbon nanotube networking

    CERN Document Server

    Karachevtsev, V A; Zarudnev, E S; Karachevtsev, M V; Leontiev, V S; Linnik, A S; Lytvyn, O S; Plokhotnichenko, A M; Stepanian, S G

    2012-01-01

    When elaborating the biosensor based on single-walled carbon nanotubes (SWNTs), it is necessary to solve such an important problem as the immobilization of a target biomolecule on the nanotube surface. In this work, the enzyme (glucose oxidase (GOX)) was immobilized on the surface of a nanotube network, which was created by the deposition of nanotubes from their solution in 1,2-dichlorobenzene by the spray method. 1-Pyrenebutanoic acid succinimide ester (PSE) was used to form the molecular interface, the bifunctional molecule of which provides the covalent binding with the enzyme shell, and its other part (pyrene) is adsorbed onto the nanotube surface. First, the usage of such a molecular interface leaves out the direct adsorption of the enzyme (in this case, its activity decreases) onto the nanotube surface, and, second, it ensures the enzyme localization near the nanotube. The comparison of the resonance Raman (RR) spectrum of pristine nanotubes with their spectrum in the PSE environment evidences the creat...

  10. Characterization of Glucose Oxidase from Penicillium notatum

    Directory of Open Access Journals (Sweden)

    Nabeela Saleem

    2009-01-01

    Full Text Available In the present study glucose oxidase (GOD has been isolated from a culture filtrate of Penicillium notatum. The enzyme was purified by ammonium sulphate precipitation, diethylaminoethyl (DEAE cellulose ion-exchange chromatography and Sephadex gel filtration. This protocol gave 16.47-fold purification and 25 % recovery of the enzyme. The optimum pH and temperature for the activity were 5.4 and 45 °C, respectively. The Km and vmax values for the enzyme were 10.5 mM and 456 U/mg, respectively. A detailed kinetic study of thermal inactivation was carried out. Both enthalpy of activation (ΔH* and entropy of activation (ΔS* decreased at higher temperatures. Moreover, free energy of denaturation (ΔG* increased at higher temperature, making the enzyme thermally stable. A possible explanation for the thermal inactivation of GOD at higher temperatures is also discussed.

  11. Copper and Copper Proteins in Parkinson’s Disease

    OpenAIRE

    Sergio Montes; Susana Rivera-Mancia; Araceli Diaz-Ruiz; Luis Tristan-Lopez; Camilo Rios

    2014-01-01

    Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased pr...

  12. Transcriptome analysis of copper homeostasis genes reveals coordinated upregulation of SLC31A1,SCO1, and COX11 in colorectal cancer.

    Science.gov (United States)

    Barresi, Vincenza; Trovato-Salinaro, Angela; Spampinato, Giorgia; Musso, Nicolò; Castorina, Sergio; Rizzarelli, Enrico; Condorelli, Daniele Filippo

    2016-08-01

    Copper homeostasis and distribution is strictly regulated by a network of transporters and intracellular chaperones encoded by a group of genes collectively known as copper homeostasis genes (CHGs). In this work, analysis of The Cancer Genome Atlas database for somatic point mutations in colorectal cancer revealed that inactivating mutations are absent or extremely rare in CHGs. Using oligonucleotide microarrays, we found a strong increase in mRNA levels of the membrane copper transporter 1 protein [CTR1; encoded by the solute carrier family 31 member 1 gene (SLC31A1 gene)] in our series of colorectal carcinoma samples. CTR1 is the main copper influx transporter and changes in its expression are able to induce modifications of cellular copper accumulation. The increased SLC31A1 mRNA level is accompanied by a parallel increase in transcript levels for copper efflux pump ATP7A, copper metabolism Murr1 domain containing 1 (COMMD1), the cytochrome C oxidase assembly factors [synthesis of cytochrome c oxidase 1 (SCO1) and cytochrome c oxidase copper chaperone 11 (COX11)], the cupric reductase six transmembrane epithelial antigen of the prostate (STEAP3), and the metal-regulatory transcription factors (MTF1, MTF2) and specificity protein 1 (SP1). The significant correlation between SLC31A1,SCO1, and COX11 mRNA levels suggests that this transcriptional upregulation might be part of a coordinated program of gene regulation. Transcript-level upregulation of SLC31A1,SCO1, and COX11 was also confirmed by the analysis of different colon carcinoma cell lines (Caco-2, HT116, HT29) and cancer cell lines of different tissue origin (MCF7, PC3). Finally, exon-level expression analysis of SLC31A1 reveals differential expression of alternative transcripts in colorectal cancer and normal colonic mucosa.

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

    Science.gov (United States)

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

    2016-10-25

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

  14. Jiangxi Copper Plans to Increase its Refined Copper Output

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>According to news published on March 30th, China’s largest copper producer--Jiangxi Copper alleged in its 2010 Financial Report Statement that it plans to improve its output of refined copper by 4.4% in 2011, to increase from 900,000 tonnes last year to 940,000 tons.

  15. Synthesis, Spectroscopy, Thermal Analysis, Electrochemistry and Superoxide Scavenging Activity of a New Bimetallic Copper(II Complex

    Directory of Open Access Journals (Sweden)

    Babita Sarma

    2013-01-01

    Full Text Available A new bimetallic copper(II complex has been synthesized with ligand obtained by the condensation of salicylaldehyde and the amine derived from reduction of nitration product of benzil. The ligand was characterized by 1H NMR and mass spectra, and the binuclear Copper(II complex was characterized by vibrational and electronic spectra, EPR spectra, and magnetic moment measurement. Thermogravimetric analysis study and electrochemical study of the complex were also done. The complex was found to show superoxide dismutase activity.

  16. Synthesis and Characterization of Porphyrin.Trisbenzimidazole Dinucleating Ligand and Its Heterodinuclear Complex as CcO Active Site Model

    Institute of Scientific and Technical Information of China (English)

    LuWei-bing; WangCun-xin; DengLi-zhi; ZhouXiao-hai; RenJian-guo

    2003-01-01

    A new dinucleating ligand having two metalbinding sites has been designed and synthesized as model ligand for Cytochrome c Oxidase. The corresponding heterodinuclear complex, as an active site model of Cytochrome c Oxidase, consisting of a porphyrinatocobalt compound covalently linked with a copper derivative of tris(2-benzimidazylmethyl)amine bearing three benzimidazole ligands for copper was synthesized and spectroscopically characterized. The spectra data suggest that there are interactions between the cobalt and copper coordination units. The cobalt is coordinated to four central nitrogens of the porphyrin and the copper has pentacoordinate geometry with the four tertiary amine nitrogens and a chloride.

  17. Portability of oxidase domains in nonribosomal peptide synthetase modules.

    Science.gov (United States)

    Schneider, Tanya L; Walsh, Christopher T

    2004-12-21

    Oxazole and thiazole rings are present in numerous nonribosomal peptide natural products. Oxidase domains are responsible for catalyzing the oxidation of thiazolines and oxazolines to yield fully aromatic heterocycles. Unlike most domains, the placement of oxidase domains within assembly line modules varies. Noting this tolerance, we investigated the portability of an oxidase domain to a heterologous assembly line. The epimerase domain of PchE, involved in pyochelin biosynthesis, was replaced with the oxidase domain from MtaD, involved in myxothiazol biosynthesis. The chimeric module was expressed in soluble form as a flavin mononucleotide-containing flavoprotein. The functionality of the inserted oxidase domain was assayed within PchE and in transfer of the growing siderophore acyl chain from PchE to the next downstream module. While pyochelin-like product release was not observed downstream, the robust activity of the transplanted oxidase domain and the ability of the chimeric module to produce an advanced intermediate bound to the synthetase underscore the possibility of future engineering within nonribosomal peptide synthetase pathways using oxidase domains.

  18. Biogenic amines in italian pecorino cheese.

    Science.gov (United States)

    Schirone, Maria; Tofalo, Rosanna; Visciano, Pierina; Corsetti, Aldo; Suzzi, Giovanna

    2012-01-01

    The quality of distinctive artisanal cheeses is closely associated with the territory of production and its traditions. Pedoclimatic characteristics, genetic autochthonous variations, and anthropic components create an environment so specific that it would be extremely difficult to reproduce elsewhere. Pecorino cheese is included in this sector of the market and is widely diffused in Italy (∼62.000t of production in 2010). Pecorino is a common name given to indicate Italian cheeses made exclusively from pure ewes' milk characterized by a high content of fat matter and it is mainly produced in the middle and south of Italy by traditional procedures from raw or pasteurized milk. The microbiota plays a major role in the development of the organoleptic characteristics of the cheese but it can also be responsible for the accumulation of undesirable substances, such as biogenic amines (BA). Bacterial amino acid decarboxylase activity and BA content have to be investigated within the complex microbial community of raw milk cheese for different cheese technologies. The results emphasize the necessity of controlling the indigenous bacterial population responsible for high production of BA and the use of competitive adjunct cultures could be suggested. Several factors can contribute to the qualitative and quantitative profiles of BA's in Pecorino cheese such as environmental hygienic conditions, pH, salt concentration, water activity, fat content, pasteurization of milk, decarboxylase microorganisms, starter cultures, temperature and time of ripening, storage, part of the cheese (core, edge), and the presence of cofactor (pyridoxal phosphate, availability of aminases and deaminases). In fact physico-chemical parameters seem to favor biogenic amine-positive microbiota; both of these environmental factors can easily be modulated, in order to control growth of undesirable microorganisms. Generally, the total content of BA's in Pecorino cheeses can range from about 100-2400

  19. Coexistence of Copper in the Iron-Rich Particles of Aceruloplasminemia Brain.

    Science.gov (United States)

    Yoshida, Kunihiro; Hayashi, Hisao; Wakusawa, Shinya; Shigemasa, Ryota; Koide, Ryoji; Ishikawa, Tetsuya; Tatsumi, Yasuaki; Kato, Koichi; Ohara, Shinji; Ikeda, Shu-Ichi

    2017-01-01

    The interaction between iron and copper has been discussed in association with human health and diseases for many years. Ceruloplasmin, a multi-copper oxidase, is mainly involved in iron metabolism and its genetic defect, aceruloplasminemia (ACP), shows neurological disorders and diabetes associated with excessive iron accumulation, but little is known about the state of copper in the brain. Here, we investigated localization of these metals in the brains of three patients with ACP using electron microscopes equipped with an energy-dispersive x-ray analyzer. Histochemically, iron deposition was observed mainly in the basal ganglia and dentate nucleus, and to lesser degree in the cerebral cortex of the patients, whereas copper grains were not detected. X-ray microanalysis identified two types of iron-rich particles in their brains: dense bodies, namely hemosiderins, and their aggregated inclusions. A small number of hemosiderins and most inclusions contained a significant amount of copper which was enough for distinct Cu x-ray images. These copper-containing particles were observed more frequently in the putamen and dentate nucleus than the cerebral cortex. Coexistence of iron and copper was supported by good correlations in the molecular ratios between these two metals in iron-rich particles with Cu x-ray image. Iron-dependent copper accumulation in iron-rich particles may suggest that copper recycling is enhanced to meet the increased requirement of cuproproteins in iron overload brain. In conclusion, the iron-rich particles with Cu x-ray image were found in the ACP brain.

  20. Amine reclaiming technologies in post-combustion carbon dioxide capture.

    Science.gov (United States)

    Wang, Tielin; Hovland, Jon; Jens, Klaus J

    2015-01-01

    Amine scrubbing is the most developed technology for carbon dioxide (CO2) capture. Degradation of amine solvents due to the presence of high levels of oxygen and other impurities in flue gas causes increasing costs and deterioration in long term performance, and therefore purification of the solvents is needed to overcome these problems. This review presents the reclaiming of amine solvents used for post combustion CO2 capture (PCC). Thermal reclaiming, ion exchange, and electrodialysis, although principally developed for sour gas sweetening, have also been tested for CO2 capture from flue gas. The three technologies all have their strengths and weaknesses, and further development is needed to reduce energy usage and costs. An expected future trend for amine reclamation is to focus on process integration of the current reclaiming technologies into the PCC process in order to drive down costs.

  1. Amine reclaiming technologies in post-combustion carbon dioxide capture

    Institute of Scientific and Technical Information of China (English)

    Tielin Wang; Jon Hovland; KlauS J.Jens

    2015-01-01

    Amine scrubbing is the most developed technology for carbon dioxide (CO2) capture.Degradation of amine solvents due to the presence of high levels of oxygen and other impurities in flue gas causes increasing costs and deterioration in long term performance,and therefore purification of the solvents is needed to overcome these problems.This review presents the reclaiming of amine solvents used for post combustion CO2 capture (PCC).Thermal reclaiming,ion exchange,and electrodialysis,although principally developed for sour gas sweetening,have also been tested for CO2 capture from flue gas.The three technologies all have their strengths and weaknesses,and further development is needed to reduce energy usage and costs.An expected future trend for amine reclamation is to focus on process integration of the current reclaiming technologies into the PCC process in order to drive down costs.

  2. Silver-catalyzed synthesis of amides from amines and aldehydes

    Science.gov (United States)

    Madix, Robert J; Zhou, Ling; Xu, Bingjun; Friend, Cynthia M; Freyschlag, Cassandra G

    2014-11-18

    The invention provides a method for producing amides via the reaction of aldehydes and amines with oxygen adsorbed on a metallic silver or silver alloy catalyst. An exemplary reaction is shown in Scheme 1: (I), (II), (III). ##STR00001##

  3. Biogenic amines in meat and fermented meat products

    Directory of Open Access Journals (Sweden)

    Joanna Stadnik

    2010-09-01

    Full Text Available Recent trends in food quality and safety promote an increasing search for trace compounds that can affect human health. Biogenic amines belong to this group of substances. They can cause distinctive pharmacological, physiological and toxic effects in organisms. Their amounts are usually increasing as a consequence of the use of poor quality raw materials, during controlled or spontaneous microbial fermentation or in the course of food spoilage. The origin of biogenic amines makes them suitable as chemical indicators of the hygienic quality and freshness of some foods being associated to the degree of food fermentation or degradation. The development of appropriate manufacturing technologies to obtain products free or nearly free from biogenic amines is a challenge for the meat industry. This review briefly summarises current knowledge on the biological implications of biogenic amines on human health and collects data on the factors affecting their formation in meat and fermented meat products.

  4. FTIR Study of Enhanced Polymeric Blend Membrane with Amines

    Directory of Open Access Journals (Sweden)

    Asim Mushtaq

    2014-03-01

    Full Text Available In this study, research will be carried out to identify the functional group behavior of glassy and rubbery polymeric blend membrane with amines. Polymeric blend membranes with different blending ratios were prepared and the developed membranes were characterized by FTIR to see the effect of blend ratio on different functional groups. The developed membranes are flat dense sheet membrane of 20% wt/wt. The pure and blend membrane polysulfone, polyethersulfone, polyvinyl acetate with different composition, with 10% methyl diethanol amine, mono ethanol amine, diethanol amine are developed with dimethyl acetamide solvent. Fourier Transform Infrared (FTIR spectroscopy was utilized to study the interaction between two polymers and to analyze the type of bonding present. To observed frequencies were assigned to various mode of vibration in terms of fundamentals and combination. These spectral changes indicated the existence of molecular interaction among the enhanced polymeric blends; highlight the compatible nature among each other.

  5. incidence of biogenic amines in foods implications for the gambia

    African Journals Online (AJOL)

    Temechegn

    These could be controlled for a better and improved food quality. ... usually operate cold chain facilities and market their products to retailers in cartons and to household ... A survey on free biogenic amine content of fresh and preserved.

  6. Study on the Reaction of Benzimidazolium Salt with Amine Compounds

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The addition-hydrolysis reaction of benzimidazolium salt with some mono- andbifunctional amine nucleophiles is reported, and a novel method of biomimetic synthesis forformamides and heterocycle compounds is provided.

  7. [Copper metabolism and genetic disorders].

    Science.gov (United States)

    Shimizu, Norikazu

    2016-07-01

    Copper is one of essential trace elements. Copper deficiency lead to growth and developmental failure and/or neurological dysfunction. However, excess copper is also problems for human life. There are two disorders of inborn error of copper metabolism, Menkes disease and Wilson disease. Menkes disease is an X linked recessive disorder with copper deficiency and Wilson disease is an autosomal recessive disorder with copper accumulation. These both disorders result from the defective functioning of copper transport P-type ATPase, ATP7A of Menkes disease and ATP7B of Wilson disease. In this paper, the author describes about copper metabolism of human, and clinical feature, diagnosis and treatment of Menkes disease and Wilson disease.

  8. Characterization of novel thermostable bacterial Laccase-like multi-copper oxidases

    DEFF Research Database (Denmark)

    Brander, Søren; Mikkelsen, Jørn Dalgaard

    cultured from a hot dirt patch in Yellowstone National Park. It belongs to the evolutionary interesting phylum Chloroflexi that has been proposed to represent some of the earliest lifeforms on Earth. The genome of T. terrenum codes for a LMCO, and we have expressed and characterized the enzyme...

  9. Parameters that enhance the bacterial expression of active plant polyphenol oxidases.

    Directory of Open Access Journals (Sweden)

    Mareike E Dirks-Hofmeister

    Full Text Available Polyphenol oxidases (PPOs, EC 1.10.3.1 are type-3 copper proteins that enzymatically convert diphenolic compounds into their corresponding quinones. Although there is significant interest in these enzymes because of their role in food deterioration, the lack of a suitable expression system for the production of soluble and active plant PPOs has prevented detailed investigations of their structure and activity. Recently we developed a bacterial expression system that was sufficient for the production of PPO isoenzymes from dandelion (Taraxacum officinale. The system comprised the Escherichia coli Rosetta 2 (DE3 [pLysSRARE2] strain combined with the pET-22b(+-vector cultivated in auto-induction medium at a constant low temperature (26 °C. Here we describe important parameters that enhance the production of active PPOs using dandelion PPO-2 for proof of concept. Low-temperature cultivation was essential for optimal yields, and the provision of CuCl2 in the growth medium was necessary to produce an active enzyme. By increasing the copper concentration in the production medium to 0.2 mM, the yield in terms of PPO activity per mol purified protein was improved 2.7-fold achieving a v(max of 0.48 ± 0.1 µkat per mg purified PPO-2 for 4-methylcatechol used as a substrate. This is likely to reflect the replacement of an inactive apo-form of the enzyme with a correctly-folded, copper-containing counterpart. We demonstrated the transferability of the method by successfully expressing a PPO from tomato (Solanum lycopersicum showing that our optimized system is suitable for the analysis of further plant PPOs. Our new system therefore provides greater opportunities for the future of research into this economically-important class of enzymes.

  10. Determination of catechin in green tea using a catechol oxidase biomimetic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Suellen C.; Osorio, Renata El-Hage M. de Barros; Anjos, Ademir dos; Neves, Ademir; Micke, Gustavo Amadeu; Vieira, Iolanda C. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Quimica]. E-mail: iolanda@qmc.ufsc.br

    2008-07-01

    A catechol oxidase biomimetic sensor, based on a novel copper(II) complex, was developed for the determination of catechin in green tea and the results were compared with those obtained by capillary electrophoresis. The dinuclear copper(II) complex, [Cu{sub 2}(HL)({mu}-CH{sub 3}COO)](ClO{sub 4}), containing the ligand N,N-[bis-(2-pyridylmethyl)]-N',N'-[(2-hydroxybenzyl)(2-hydroxy-3,5-di-tert - butylbenzyl)]-1,3-propanediamine-2-ol (H{sub 3}L), was synthesized and characterized by IR, {sup 1}H NMR and elemental analysis. The best conditions for the optimization of the biomimetic sensor were established by square wave voltammetry. The best performance for this sensor was obtained in 75:15:10% (m/m/m) of the graphite powder:nujol:copper(II) complex, 0.05 mol L{sup -1} phosphate buffer solution (pH 7.5) and frequency, pulse amplitude, scan increment at 30 Hz, 80 mV, 3.3 mV, respectively. The analytical curve was linear in the concentration range 4.95 x 10{sup -6} to 3.27 x 10{sup -5} mol L{sup -1} (r = 0.9993) with a detection limit of 2.8 x 10{sup -7} mol L{sup -1}. This biomimetic sensor demonstrated long-term stability (9 months; 800 determinations) and reproducibility with a relative standard deviation of 3.5%. The recovery of catechin from green tea samples ranged from 93.8 to 106.9% and the determination, compared with that obtained using capillary electrophoresis, was found to be acceptable at the 95% confidence level. (author)

  11. Direct regulation of cytochrome c oxidase by calcium ions.

    Directory of Open Access Journals (Sweden)

    Tatiana Vygodina

    Full Text Available Cytochrome c oxidase from bovine heart binds Ca(2+ reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca(2+ shifts the absorption spectrum of heme a, which allowed previously to determine the kinetics and equilibrium characteristics of the binding. However, no effect of Ca(2+ on the functional characteristics of cytochrome oxidase was revealed earlier. Here we report that Ca(2+ inhibits cytochrome oxidase activity of isolated bovine heart enzyme by 50-60% with Ki of ∼1 µM, close to Kd of calcium binding with the oxidase determined spectrophotometrically. The inhibition is observed only at low, but physiologically relevant, turnover rates of the enzyme (∼10 s(-1 or less. No inhibitory effect of Ca(2+ is observed under conventional conditions of cytochrome c oxidase activity assays (turnover number >100 s(-1 at pH 8, which may explain why the effect was not noticed earlier. The inhibition is specific for Ca(2+ and is reversed by EGTA. Na(+ ions that compete with Ca(2+ for binding with the Cation Binding Site, do not affect significantly activity of the enzyme but counteract the inhibitory effect of Ca(2+. The Ca(2+-induced inhibition of cytochrome c oxidase is observed also with the uncoupled mitochondria from several rat tissues. At the same time, calcium ions do not inhibit activity of the homologous bacterial cytochrome oxidases. Possible mechanisms of the inhibition are discussed as well as potential physiological role of Ca(2+ binding with cytochrome oxidase. Ca(2+- binding at the Cation Binding Site is proposed to inhibit proton-transfer through the exit part of the proton conducting pathway H in the mammalian oxidases.

  12. Copper dependence of angioproliferation in pulmonary arterial hypertension in rats and humans.

    Science.gov (United States)

    Bogaard, Harm J; Mizuno, Shiro; Guignabert, Christophe; Al Hussaini, Aysar A; Farkas, Daniela; Ruiter, Gerrina; Kraskauskas, Donatas; Fadel, Elie; Allegood, Jeremy C; Humbert, Marc; Vonk Noordegraaf, Anton; Spiegel, Sarah; Farkas, Laszlo; Voelkel, Norbert F

    2012-05-01

    Obliteration of the vascular lumen by endothelial cell growth is a hallmark of many forms of severe pulmonary arterial hypertension. Copper plays a significant role in the control of endothelial cell proliferation in cancer and wound-healing. We sought to determine whether angioproliferation in rats with experimental pulmonary arterial hypertension and pulmonary microvascular endothelial cell proliferation in humans depend on the proangiogenic action of copper. A copper-depleted diet prevented, and copper chelation with tetrathiomolybdate reversed, the development of severe experimental pulmonary arterial hypertension. The copper chelation-induced reopening of obliterated vessels was caused by caspase-independent apoptosis, reduced vessel wall cell proliferation, and a normalization of vessel wall structure. No evidence was found for a role of super oxide-1 inhibition or lysyl-oxidase-1 inhibition in the reversal of angioproliferation. Tetrathiomolybdate inhibited the proliferation of human pulmonary microvascular endothelial cells, isolated from explanted lungs from control subjects and patients with pulmonary arterial hypertension. These data suggest that the inhibition of endothelial cell proliferation by a copper-restricting strategy could be explored as a new therapeutic approach in pulmonary arterial hypertension. It remains to be determined, however, whether potential toxicity to the right ventricle is offset by the beneficial pulmonary vascular effects of antiangiogenic treatment in patients with pulmonary arterial hypertension.

  13. Synthesis and Crystal Structure of Copper(II) Complex with Mixed Bipyridine and 2-Hydroxy-1-naphthaldehyde Ligands

    Institute of Scientific and Technical Information of China (English)

    卜平宇; 程鹏; 赵斌; 阎世平; 瘳代正; 姜宗慧; 刘松岩; 姚心侃; 王宏根

    2002-01-01

    A mononuclear copper(II) complex, [Cu(bipy)(naph)(ClO4)] (where bipy is bipyridine and naph is 2-hydroxy-1-naphthaldehyde), was synthesized and characterized by X-ray single-crystal structure analysis. The crystal is triclinic, space group P ī with a = 9.245(4), b = 9.962(4), c = 10.809(7) A, α = 84.83(5), β =82.35(4), γ = 81.02(4)°, V = 972.1 >3, C21H15ClCuN2O6 Mr = 490.36, Z = 2, F(000) = 498, Dx = 1.68 g/cm3, μ = 13.05 cm-1, R = 0.078, Rw = 0.081 for 2295 observed reflections with I > 3σ(I). The copper(II) ion is coordinated by two nitrogen atoms of bipy and two oxygen atoms of naph in the equatorial plane, with an axial perchlorate oxygen-copper(II) bond to copper(II) ion to form square-pyramidal coordination geometry. The coordination environment of copper(II) is similar to the active site of galactose oxidase and this compound may also be considered as the structural model of galactose oxidase.

  14. Catalyst Deactivation Reactions : The Role of Tertiary Amines Revisited

    NARCIS (Netherlands)

    Novarino, Elena; Rios, Itzel Guerrero; van der Veer, Siebe; Meetsma, Auke; Hessen, Bart; Bouwkamp, Marco W.

    2011-01-01

    Decamethylzirconocene cation [Cp*2ZrMe](+) (2) decomposes in bromobenzene-d(5) solution to generate sigma-aryl species [Cp*Zr-2(2-C6H4Br-kappa Br,C)][B(C6F5)(4)] (3). This a-bond metathesis reaction is catalyzed by tertiary amines via a two-step mechanism, in which the amine acts as a proton relay.

  15. Isomerization of metastable amine radical cations by dissociation-recombination

    DEFF Research Database (Denmark)

    Pedersen, Anders Holmen; Nielsen, Christian Benedikt; Bojesen, Gustav;

    2015-01-01

    The metastable molecular ions of primary aliphatic amines branched at C2 can isomerize by cleavage-recombination, thereby facilitating fragmentation reactions that require less energy than simple cleavage of the initial molecular ion. This process complements the reactions described by Audier...... to account for the conspicuous absence of the conventional a-cleavage among the major fragmentation reactions of the metastable molecular ions of primary amines....

  16. Intercalating quaternary nicotinamide-based poly(amido amine)s for gene delivery.

    Science.gov (United States)

    van der Aa, L J; Vader, P; Storm, G; Schiffelers, R M; Engbersen, J F J

    2014-12-10

    In the development of potent polymeric gene carriers for gene therapy, a good interaction between the polymer and the nucleotide is indispensable to form small and stable polyplexes. Polymers with relatively high cationic charge density are frequently used to provide these interactions, but high cationic charge is usually associated with severe cytotoxicity. In this study an alternative, nucleotide specific binding interaction based on intercalation was investigated to improve polymer/pDNA complex formation. For this purpose bioreducible poly(amido amine) copolymers (p(CBA-ABOL/Nic)) were synthesized with different degrees of intercalating quaternary nicotinamide (Nic) groups and amide-substituted derivatives in their side chains. The quaternary nicotinamide group was chosen as intercalating moiety because this group is part of the naturally occurring NAD+ coenzyme and is therefore expected to be non-toxic and non-carcinogenic. The presence of the quaternary nicotinamide moieties in the poly(amido amine) copolymers showed to effectively promote self-assembled polyplex formation already at low polymer/DNA ratios and results in decreased polyplex size and increased stability of the polyplexes. Furthermore, in contrast to the primary amine functionalized analogs the quaternary nicotinamide polymers showed to be non-hemolytic, indicating their compatibility with cell membranes. Polymers with 25% of Nic in the side chains induced GFP expressions of about 4-5 times that of linear PEI, which is comparable with p(CBA-ABOL), the parent PAA without Nic, but at a two- to fourfold lower required polymer dose. N-phenylation of the nicotinamide functionality even further reduces the required polymer dose to form stable polyplexes, which is a major improvement for these kinds of cationic polymers. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Direct electrochemistry of dinuclear Cu{sub A} fragment from cytochrome c oxidase of Thermus thermophilus at surfactant modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Rajbongshi, Jitumani [Department of Chemistry, Gauhati University, Guwahati 14 (India); Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, Maharashtra 5 (India); Das, Diganta Kumar [Department of Chemistry, Gauhati University, Guwahati 14 (India); Mazumdar, Shyamalava, E-mail: shyamal@tifr.res.i [Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, Maharashtra 5 (India)

    2010-05-01

    Cytochrome c oxidase is ubiquitous enzyme involved in the terminal step of respiratory electron transfer process. The unique binuclear copper center containing bis-dithiolato bridges form a valance delocalized [Cu{sup 1.5+}-Cu{sup 1.5+}] state of the metal center located at the subunit II of cytochrome c oxidase. This metal center acts as the electron entry site of the enzyme and accepts electrons from cytochrome c. Direct electrochemistry of this binuclear copper center containing the water soluble protein obtained by genetically truncating the membrane bound part of the subunit II from Thermus thermophilus was achieved by favorable orientation of the protein on glassy carbon electrode surface promoting efficient electron transfer in the presence of various surfactants. Very reproducible, Nernstian responses are obtained with Cu{sub A}. The redox potential and the electrochemical response were enhanced prominently in case of cationic surfactant CTAB indicating that the nature of the surfactant has a significant effect on the microenvironment of the protein-electrode interface. The results have been used to understand the mechanism of electron transfer from cytochrome c to the copper center during the enzymatic reaction.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Laura Pastorino

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

  20. STRUCTURAL EFFECT ON VINYL POLYMERIZATION INITIATED WITH AROMATIC TERTIARY AMINE

    Institute of Scientific and Technical Information of China (English)

    CAO Weixiao; FENG Xinde

    1983-01-01

    The polymerization mechanism of various vinyl monomers in the presence of aromatic tertiary amines has been studied. It was found that the mechanisms of different monomers are varied with the structures of monomers. Those monomers, such as methacrylic esters containing α-CH3 group on the double bond could be polymerized with aromatic tertiary amine in the absence of light,while the monomers without α-CH3 group, such as methyl acrylate, acrylonitrile etc. would polymerize only under light.The structural effects, both of the monomer and the amine, on the rate of photopolymerization were studied. The activities of monomers and amines may be arranged in the following orderMonomer: AN>MA>VA>St Amine: DMT>DMA>DMB>DNAIt is revealed that both the electro-negative group on the double bond of monomer which acts as an acceptor and the electro-positive group on the nitrogen atom of amine which acts as a donor would effectively increase the rate of photopolymerization.