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Littérature scientifique sur le sujet « Pyruvoyl enzymes »

Auteur : Grafiati

Publié le 4 juin 2021

Mis à jour le 1 février 2022

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Articles de revues sur le sujet "Pyruvoyl enzymes"

van Poelje, Paul D., et Esmond E. Snell. « Pyruvoyl-Dependent Enzymes ». Annual Review of Biochemistry 59, n^o 1 (juin 1990) : 29–59. http://dx.doi.org/10.1146/annurev.bi.59.070190.000333.

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Kim, Alexander D., David E. Graham, Steven H. Seeholzer et George D. Markham. « S-Adenosylmethionine Decarboxylase from the Archaeon Methanococcus jannaschii : Identification of a Novel Family of Pyruvoyl Enzymes ». Journal of Bacteriology 182, n^o 23 (1 décembre 2000) : 6667–72. http://dx.doi.org/10.1128/jb.182.23.6667-6672.2000.

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ABSTRACT Polyamines are present in high concentrations in archaea, yet little is known about their synthesis, except by extrapolation from bacterial and eucaryal systems. S-Adenosylmethionine (AdoMet) decarboxylase, a pyruvoyl group-containing enzyme that is required for spermidine biosynthesis, has been previously identified in eucarya and Escherichia coli. Despite spermidine concentrations in the Methanococcales that are several times higher than in E. coli, no AdoMet decarboxylase gene was recognized in the complete genome sequence ofMethanococcus jannaschii. The gene encoding AdoMet decarboxylase in this archaeon is identified herein as a highly diverged homolog of the E. coli speD gene (less than 11% identity). The M. jannaschii enzyme has been expressed inE. coli and purified to homogeneity. Mass spectrometry showed that the enzyme is composed of two subunits of 61 and 63 residues that are derived from a common proenzyme; these proteins associate in an (αβ)2 complex. The pyruvoyl-containing subunit is less than one-half the size of that in previously reported AdoMet decarboxylases, but the holoenzyme has enzymatic activity comparable to that of other AdoMet decarboxylases. The sequence of theM. jannaschii enzyme is a prototype of a class of AdoMet decarboxylases that includes homologs in other archaea and diverse bacteria. The broad phylogenetic distribution of this group suggests that the canonical SpeD-type decarboxylase was derived from an archaeal enzyme within the gamma proteobacterial lineage. Both SpeD-type and archaeal-type enzymes have diverged widely in sequence and size from analogous eucaryal enzymes.

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Shik Park, Young, Nacksung Kim, Hajeong Kim, Dongkook Park et Jeongbin Yim. « Expression and Characterization of Recombinant Drosophila 6-pyruvoyl tetrahydropterin Synthase ». Pteridines 6, n^o 2 (mai 1995) : 58–62. http://dx.doi.org/10.1515/pteridines.1995.6.2.58.

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Summary 6-Pyruvoyl tetrahydropterin synthase is involved in the synthesis of pteridine eye pigments in Drosophila. The purple gene which was known to be one of the target loci of the suppressor mutation su(sj2 has been identified to encode the enzyme, and its cDNA has been cloned recently. The cDNA encoding the 19.3 kDa subunit of the 6-pyruvoyl tetrahydropterin synthase was expressed as fusion proteins in E. coli. The recombinant protein was shown to be active and purified from the E. coli crude extract by metal-chelation chromatography. The fused metal-chelating oilgopeptide was removed by thrombin for further characterization. Apparent Km for the substrate dihydroneopterin triphosphate was determined to be 590 IlM, which was slightly higher than the value of the native enzyme. The isoelectric point of 6.4 was also different from the known value of 4.3 determined by the native enzyme. Heat stability and the stimulatory effect of reducing agents were similar to the native enzyme. The modification of cysteine residues in the recombinant enzyme, one of which is known to be conserved in human and rat enzymes, by iodoacetamide inhibited its activity by up to 80%.

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THÖNY, Beat, Günter AUERBACH et Nenad BLAU. « Tetrahydrobiopterin biosynthesis, regeneration and functions ». Biochemical Journal 347, n^o 1 (27 mars 2000) : 1–16. http://dx.doi.org/10.1042/bj3470001.

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Tetrahydrobiopterin (BH4) cofactor is essential for various processes, and is present in probably every cell or tissue of higher organisms. BH4 is required for various enzyme activities, and for less defined functions at the cellular level. The pathway for the de novo biosynthesis of BH4 from GTP involves GTP cyclohydrolase I, 6-pyruvoyl-tetrahydropterin synthase and sepiapterin reductase. Cofactor regeneration requires pterin-4a-carbinolamine dehydratase and dihydropteridine reductase. Based on gene cloning, recombinant expression, mutagenesis studies, structural analysis of crystals and NMR studies, reaction mechanisms for the biosynthetic and recycling enzymes were proposed. With regard to the regulation of cofactor biosynthesis, the major controlling point is GTP cyclohydrolase I, the expression of which may be under the control of cytokine induction. In the liver at least, activity is inhibited by BH4, but stimulated by phenylalanine through the GTP cyclohydrolase I feedback regulatory protein. The enzymes that depend on BH4 are the phenylalanine, tyrosine and tryptophan hydroxylases, the latter two being the rate-limiting enzymes for catecholamine and 5-hydroxytryptamine (serotonin) biosynthesis, all NO synthase isoforms and the glyceryl-ether mono-oxygenase. On a cellular level, BH4 has been found to be a growth or proliferation factor for Crithidia fasciculata, haemopoietic cells and various mammalian cell lines. In the nervous system, BH4 is a self-protecting factor for NO, or a general neuroprotecting factor via the NO synthase pathway, and has neurotransmitter-releasing function. With regard to human disease, BH4 deficiency due to autosomal recessive mutations in all enzymes (except sepiapterin reductase) have been described as a cause of hyperphenylalaninaemia. Furthermore, several neurological diseases, including Dopa-responsive dystonia, but also Alzheimer's disease, Parkinson's disease, autism and depression, have been suggested to be a consequence of restricted cofactor availability.

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Blau, Nenad, Beat Thöny, Claus W. Heizmann et Jean-Louis Dhondt. « Tetrahydrobiopterin Deficiency : From Phenotype to Genotype ». Pteridines 4, n^o 1 (février 1993) : 1–10. http://dx.doi.org/10.1515/pteridines.1993.4.1.1.

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Summary As a result of the selective screening worldwide during the last 18 years, approximately 250 patients with tetrahydrobiopterin deficiency were discovered. Most patients suffer from 6-pyruvoyl tetrahydropterin synthase deficiency (58%), followed by dihydropteridine reductase deficiency (35%), GTP cyclohydrolase I deficiency (3%), and “primapterinuria” (4%). The patients can be treated with neurotransmitter precursors, as well as with tetrahydrobiopterin. However, data on long term treatment are still scarce and it is therefore of great value to investigate all newborns with even mild hyperphenylalaninemia. Cloning of the enzymes involved in the biosynthesis and regeneration of tetrahydrobiopterin makes them to be easily accessible for biochemical and biological studies. So far, all proteins expressed heterologous are active in E. coli. Cloning of the wild type gene and mutant analysis of patients allow the rapid identification of the defective gene on the molecular level.

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Killivalavan, Asaithambi, Kyung Seo, Ningning Zhuang, Young Park et Kon Lee. « Structural analysis of E. coli 6-carboxytetrahydropterin synthase ». Acta Crystallographica Section A Foundations and Advances 70, a1 (5 août 2014) : C462. http://dx.doi.org/10.1107/s2053273314095370.

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The Escherichia coli 6-carboxytetrahydropterin synthase (eCTPS), a homolog of 6-pyruvoyl tetrahydropterin synthase (PTPS), possesses a much stronger catalytic activity to cleave the side chain of sepiapterin in vitro rather than the genuine PTPS activity and catalyzes the conversion of dihydroneopterin triphosphate to 6-carboxy-5,6,7,8-tetrahydropterin in vivo. We have determined crystal structures of a wild type apo-eCTPS and a Cys27Ala mutant eCTPS complexed with sepiapterin up to 2.3 and 2.5 Å, respectively. The structures are highly conserved at the active site and the Zn2+ binding site. However, comparison of the eCTPS structures with those of mammalian PTPS homologs revealed that two specific residues Trp51 and Phe55, not existing in the mammalian PTPS, kept the substrate bound by stacking it with their side chains. Replacements of these two residues by site-directed mutagenesis to the residues, Met and Leu, existing only in mammalian PTPS, converted the eCTPS to have the mammalian PTPS activity. Our studies confirm that these two aromatic residues in eCTPS play an essential role in stabilizing the substrate and for the specific enzyme activity different from the original PTPS activity. These aromatic residues Trp51 and Phe55 are a key signature of bacterial PTPS enzymes that distinguish them from mammalian PTPS homologs.

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Huynh, Q. K., et E. E. Snell. « Pyruvoyl-dependent histidine decarboxylases. Comparative sequences of cysteinyl peptides of the enzymes from Lactobacillus 30a, Lactobacillus buchneri, and Clostridium perfringens. » Journal of Biological Chemistry 260, n^o 5 (mars 1985) : 2794–97. http://dx.doi.org/10.1016/s0021-9258(18)89432-7.

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Kim, Seonhee, Ikjun Lee, Hee-Jung Song, Su-jeong Choi, Harsha Nagar, Sung-min Kim, Byeong Hwa Jeon et al. « Far-Infrared-Emitting Sericite Board Upregulates Endothelial Nitric Oxide Synthase Activity through Increasing Biosynthesis of Tetrahydrobiopterin in Endothelial Cells ». Evidence-Based Complementary and Alternative Medicine 2019 (31 octobre 2019) : 1–9. http://dx.doi.org/10.1155/2019/1813282.

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Far-infrared ray (FIR) therapy has been reported to exert beneficial effects on cardiovascular function by elevating endothelial nitric oxide synthesis (eNOS) activity and nitric oxide (NO) production. Tetrahydrobiopterin (BH4) is a key determinant of eNOS-dependent NO synthesis in vascular endothelial cells. However, whether BH4 synthesis is associated with the effects of FIR on eNOS/NO production has not yet been investigated. In this study, we investigated the effects of FIR on BH4-dependent eNOS/NO production and vascular function. We used FIR-emitting sericite boards as an experimental material and placed human umbilical vein endothelial cells (HUVECs) and Sprague–Dawley rats on the boards with or without FIR irradiation and then evaluated vascular relaxation by detecting NO generation, BH4 synthesis, and Akt/eNOS activation. Our results showed that FIR radiation significantly enhanced Akt/eNOS phosphorylation and NO production in human endothelial cells and aorta tissues. FIR can also induce BH4 storage by elevating levels of enzymes (e.g., guanosine triphosphate cyclohydrolase-1, 6-pyruvoyl tetrahydrobiopterin synthase, sepiapterin reductase, and dihydrofolate reductase), which ultimately results in NO production. These results indicate that FIR upregulated eNOS-dependent NO generation via BH4 synthesis and Akt phosphorylation, which contributes to the regulation of vascular function. This might develop potential clinical application of FIR to treat vascular diseases by augmenting the BH4/NO pathway.

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Steinerstauch, Petra, Yoshitomo Sawada, Walter Leimbacher, Sandro Ghisla et Hans-Christoph Curtius. « Purification and Characterization of a Carbonyl Reductase from Human Liver, which is Competent in the Reduction of 6-Pyruvoyl-Tetrahydropterin ». Pteridines 1, n^o 4 (novembre 1989) : 189–98. http://dx.doi.org/10.1515/pteridines.1989.1.4.189.

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Summary An enzyme which reduces 6-pyruvoyl-tetrahydropterin has been purified to apparent homogeneity from human liver. It consists of a single polypeptide chain with a molecular weight of 35 kDa, has an isoelectric point of 5.9 ± 0.1 and contains no glycosyl residues. The pure enzyme has a specific activity of 450 mU/mg protein at pH 7.0 in 10 mM potassium phosphate buffer. It converts 6-pyruvoyl-tetrahydropterin to 6-lactoyltetrahydropterin by transfer of the pro 4R-hydrogen of NADPH to form the side chain -OH at position C(2') of the substrate. Km values are 1.8 J..lM for 6-pyruvoyl-tetrahydropterin and 5.5 J..lM for NADPH. Polyclonal antibodies raised against the purified enzyme recognize 6-pyruvoyl-tetrahydropterin reductase in Western blot and ELISA but do not cross-react with human sepiapterin reductase. The enzyme appears to be identical with aldose reductase.

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RAMJEE, Manoj K., Ulrich GENSCHEL, Chris ABELL et Alison G. SMITH. « Escherichia coli l-aspartate-α-decarboxylase : preprotein processing and observation of reaction intermediates by electrospray mass spectrometry ». Biochemical Journal 323, n^o 3 (1 mai 1997) : 661–69. http://dx.doi.org/10.1042/bj3230661.

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The Escherichia coli panD gene, encoding l-aspartate-α-decarboxylase, was cloned by PCR, and shown to complement apanD mutant defective in β-alanine biosynthesis. Aspartate decarboxylase is a pyruvoyl-dependent enzyme, and is synthesized initially as an inactive proenzyme (the π-protein), which is proteolytically cleaved at a specific X–Ser bond to produce a β-subunit with XOH at its C-terminus and an α-subunit with a pyruvoyl group at its N-terminus, derived from the serine. The recombinant enzyme, as purified, is a tetramer, and comprises principally the unprocessed π-subunit (of 13.8 kDa), with a small proportion of the α- and β-subunits (11 kDa and 2.8 kDa respectively). Incubation of the purified enzyme at elevated temperatures for several hours results in further processing. Using fluorescein thiosemicarbazide, the completely processed enzyme was shown to contain three pyruvoyl groups per tetrameric enzyme. The presence of unchanged serine at the N-terminus of some of the α-subunits was confirmed by electrospray mass spectrometry (ESMS) and N-terminal amino acid sequencing. A novel HPLC assay for aspartate decarboxylase was established and used to determine the Km and kcat for l-aspartate as 151±16 μM and 0.57 s-1 respectively. ESMS was also used to observe substrate and product adducts trapped on the pyruvoyl group by sodium cyanoborohydride treatment.

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Thèses sur le sujet "Pyruvoyl enzymes"

Sunde, Margaret. « N-terminal modification of S-adenosylmethionine decarboxylase ». Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318198.

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Giles, Teresa Neelima. « Pyruvoyl dependent arginine decarboxylases from Chlamydiae and Crenarchaea ». 2008. http://hdl.handle.net/2152/18622.

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Arginine decarboxylase is a key enzyme involved in the polyamine pathway of organisms. Pyruvoyl-dependent arginine decarboxylases are expressed in the form of proenzymes that self-cleave to form N-terminal [beta] and C-terminal [alpha] subunits generating an active pyruvoyl group at the [alpha] terminus. We have identified an archaeal homolog of a pyruvoyl-dependent arginine decarboxylase in Chlamydophila pneumoniae that could play a role in the persistence of the organism in the host. The recombinant enzyme showed highest activity at pH 3.4, which is the lowest optimum pH ever reported for a pyruvoyl dependent arginine decarboxylase. The proton-consuming decarboxylation raises intracellular pH, and thereby plays a role in acid-resistance. It could inhibit the pro-inflammatory nitric oxide synthase resulting in asymptomatic infection. A variant protein Thr⁵²Ser at the predicted cleavage site showed less pro-enzyme cleavage and activity compared to the wild-type. The homologs of arginine decarboxylase and flanking arginine-agmatine antiporter were also found in different biovariants of Chlamydia trachomatis. In the invasive L2 strain of C. trachomatis, the presence of a nonsense codon in the gene encoding arginine decarboxylase enzyme prevented the expression of an active enzyme. The variant protein with tryptophan replacing nonsense codon restored arginine decarboxylase activity. The non-invasive D strain of C. trachomatis had an intact arginine decarboxylase gene, but it was recombinantly expressed as a proenzyme that was uncleaved. The arginine-agmatine antiporters from both the strains were active and transported tritiated arginine into their cells. The polyamine pathway of the crenarchaeon Sulfolobus solfataricus uses arginine to make putrescine, but the organism lacks homologs of arginine decarboxylase. However, it has two paralogs of pyruvoyl dependent S-adenosylmethionine decarboxylase − SSO0536 and SSO0585. These enzymes were recombinantly expressed as pro-enzymes that self-cleaved into [beta] and [alpha] subunits. Even with a 47% amino acid sequence identity, the SSO0536 protein exhibited significant arginine decarboxylase activity whereas SSO0585 protein had significant S-adenosylmethionine decarboxylase activity. This is the first report of an S-adenosylmethionine decarboxylase enzyme showing alternative decarboxylase activity. The chimeric protein with the [alpha]-subunit of SSO0585 and [beta]-subunit of SSO0536 had arginine decarboxylase activity, suggesting that the residues responsible for substrate recognition are located in the amino terminus.
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Chapitres de livres sur le sujet "Pyruvoyl enzymes"

Dowhan, William. « [10] Phosphatidylserine decarboxylases : Pyruvoyl-dependent enzymes from bacteria to mammals ». Dans Methods in Enzymology, 81–88. Elsevier, 1997. http://dx.doi.org/10.1016/s0076-6879(97)80104-8.

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SNELL, ESMOND E. « Pyridoxal-P, The Pyruvoyl Group, and Amino Acid Decarboxylases ». Dans Enzymes Dependent on Pyridoxal Phosphate and Other Carbonyl Compounds As Cofactors, 11–20. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-08-040820-0.50007-8.

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DANZIN, C., P. MARCHAL et P. CASARA. « Enzyme-Activated Irreversible Inhibitors of S-Adenosylmethionine Decarboxylase, A Pyruvoyl Enzyme ». Dans Enzymes Dependent on Pyridoxal Phosphate and Other Carbonyl Compounds As Cofactors, 445–47. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-08-040820-0.50094-7.

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SUKANYA, N., H. S. SAVITHRI, A. N. RADHAKRISHNAN et N. APPAJI RAO. « Serine Hydroxymethyltransferase from Mung Bean Seedlings (Vigna Radiata) : A New Pyruvoyl Enzyme ». Dans Enzymes Dependent on Pyridoxal Phosphate and Other Carbonyl Compounds As Cofactors, 437–44. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-08-040820-0.50093-5.

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Frey, Perry A., et Adrian D. Hegeman. « Decarboxylation and Carboxylation ». Dans Enzymatic Reaction Mechanisms. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195122589.003.0012.

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Decarboxylation is an essential process in catabolic metabolism of essentially all nutrients that serve as sources of energy in biological cells and organisms. The most widely known biological process leading to decarboxylation is the metabolism of glucose, in which all of the carbon in the molecule is oxidized to carbon dioxide by way of the glycolytic pathway, the pyruvate dehydrogenase complex, and the tricarboxylic acid cycle. The decarboxylation steps take place in thiamine pyrophosphate (TPP)–dependent α-ketoacid dehydrogenase complexes and isocitrate dehydrogenase. The latter enzyme does not require a coenzyme, other than the cosubstrate NAD+. Many other decarboxylations require coenzymes such as pyridoxal-5'-phosphate (PLP) or a pyruvoyl moiety in the peptide chain. Biological carboxylation is the essential process in the fixation of carbon dioxide by plants and of bicarbonate by animals, plants, and bacteria. Carboxylation by enzymes requires the action of biotin or a divalent metal cofactor, and it requires ATP when the carboxylating agent is the bicarbonate ion. The most prevalent enzymatic carboxylation is that of ribulose bisphosphate carboxylase (rubisco), which is responsible for carbon dioxide fixation in plants. The basic chemistry of decarboxylation is illustrated by mechanisms A to D in fig. 8-1. The mechanisms all require some means of accommodation for the electrons from the cleavage of the bond linking the carboxylate group to the α-carbon. In mechanism A, an electron sink at the β-carbon provides a haven for two electrons. Acetoacetate decarboxylase functions by this mechanism (see chap. 1), as well as PLP- and TPP-dependent decarboxylases (see chap. 3). In mechanism B, a leaving group at the β-carbon departs with two electrons. Mevalonate-5-diphosphate decarboxylate functions by mechanism B and is discussed in a later section. In mechanism C, a leaving group replaces the α-carbon and departs with a pair of electrons. A biological example is formate dehydrogenase, in which the leaving group is a hydride that is transferred to NAD+. In mechanism D, a free radical center is created adjacent to the α-carbon and potentiates the homolytic scission of the bond to the carboxylate group. Mechanism D requires secondary electron transfer processes to create the radical center and quench the formyl radical.

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