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Mitochondrial NADH:ubiquinone oxidoreductase (complex I) in eukaryotes: A highly conserved subunit composition highlighted by mining of protein databases  

British Library Electronic Table of Contents (United Kingdom)

Complex I (NADH:ubiquinone oxidoreductase) is the largest enzyme of the mitochondrial respiratory chain. Compared to its bacterial counterpart which encompasses 14-17 subunits, mitochondrial complex I has almost tripled its subunit composition during evolution of eukaryotes, by recruitment of so-called accessory subunits, part of them being specific to distinct evolutionary lineages. The increasing availability of numerous broadly sampled eukaryotic genomes now enables the reconstruction of the evolutionary history of this large protein complex. Here, a combination of profile-based sequence comparisons and basic structural properties analyses at the protein level enabled to pinpoint homology relationships between complex I subunits from fungi, mammals or green plants, previously identified...

2011-01-01

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Functional Characterization and Partial Purification of the Ubiquinol-Cytochrome c Oxidoreductase from Higher Plant Mitochondria (Helianthus tuberosus) 1  

UK PubMed Central (United Kingdom)

The functional and thermodynamic characteristics of the ubiquinolcytochrome (Cyt) c oxidoreductase in a Cyt b/c1-enriched fraction (defined...Full Text Available

1985-03-01

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A Hyperactive NAD(P)H:Rubredoxin Oxidoreductase from the Hyperthermophilic Archaeon Pyrococcus furiosus  

UK PubMed Central (United Kingdom)

NAD(P)H:rubredoxin oxidoreductase (NROR) has been purified from the hyperthermophilic archaeon Pyrococcus furiosus. The enzyme is exceedingly active in catalyzing the NADPH-dependent...Full Text Available

1999-09-01

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New Insights into Type II NAD(P)H:Quinone Oxidoreductases  

UK PubMed Central (United Kingdom)

Type II NAD(P)H:quinone oxidoreductases (NDH-2) catalyze the two-electron transfer from NAD(P)H to quinones, without any energy-transducing site. NDH-2 accomplish the turnover of NAD(P)H, regenerating...Full Text Available

2004-12-01

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Biotransformation of Explosives by the Old Yellow Enzyme Family of Flavoproteins  

UK PubMed Central (United Kingdom)

Several independent studies of bacterial degradation of nitrate ester explosives have demonstrated the involvement of flavin-dependent oxidoreductases related to the old yellow enzyme (OYE) of yeast....Full Text Available

2004-06-01

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Strain differences in the responsiveness between Sprague-Dawley and Fischer rats to nephropathy induced by FYX-051, a xanthine oxidoreductase inhibitor  

British Library Electronic Table of Contents (United Kingdom)

To determine a rat strain appropriate for carcinogenicity testing of FYX-051, a xanthine oxidoreductase inhibitor, we performed a 4-week oral toxicity study by administering 0.3, 1 and 3?mg/kg, and 1, 3 and 10?mg/kg of FYX-051 to male Sprague-Dawley (SD) and Fischer (F344) rats, respectively. Histopathology revealed that the degree of FYX-051-induced nephropathy was 3-fold stronger in SD rats than in F344 rats. Our previous study demonstrated that the key factor of species differences in FYX-051-induced nephropathy is purine metabolism. This observation led us to examine the involvement of purine metabolism in differences among two strains of rats. However, purine metabolism was proven not to be implicated as an important factor. Subsequently, other factors responsible for the strain diffe...

2006-01-01

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The mechanism of thioredoxin reductase from human placenta is similar to the mechanisms of lipoamide dehydrogenase and glutathione reductase and is distinct from the mechanism of thioredoxin reductase from Escherichia?coli  

UK PubMed Central (United Kingdom)

Thioredoxin reductase, lipoamide dehydrogenase, and glutathione reductase are members of the pyridine nucleotide–disulfide oxidoreductase family of dimeric flavoenzymes. The mechanisms and structures...Full Text Available

1997-04-15

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Molecular Cloning and Evidence for Osmoregulation of the ?1-Pyrroline-5-Carboxylate Reductase (proC) Gene in Pea (Pisum sativum L.) 12  

UK PubMed Central (United Kingdom)

Several cDNA clones encoding Δ1-pyrroline-5-carboxylate reductase (P5CR, l-proline:NAD[P]+ 5-oxidoreductase, EC 1.5.1.2), which catalyzes the terminal step in...Full Text Available

1992-11-01

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Helicobacter pylori porCDAB and oorDABC Genes Encode Distinct Pyruvate:Flavodoxin and 2-Oxoglutarate:Acceptor Oxidoreductases Which Mediate Electron Transport to NADP  

UK PubMed Central (United Kingdom)

Helicobacter pylori, a major cause of human gastric disease, is a microaerophilic bacterium that contains neither pyruvate nor 2-oxoglutarate dehydrogenase activity. Previous studies...Full Text Available

1998-03-01

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Comparison of Human Serum Dopamine-?-Hydroxylase Levels by Radioimmunoassay and Enzymatic Assay  

UK PubMed Central (United Kingdom)

Human serum dopamine-β-hydroxylase (3,4-dihydroxyphenylethylamine, ascorbate:oxygen oxidoreductase, EC 1.14.17.1) has been measured in a normal adult population by both enzymatic assay and by...Full Text Available

1974-03-01

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Reductive metabolism of the dinitrobenzamide mustard anticancer prodrug PR-104 in mice  

British Library Electronic Table of Contents (United Kingdom)

Purpose PR-104, a bioreductive prodrug in clinical trial, is a phosphate ester which is rapidly metabolized to the corresponding alcohol PR-104A. This dinitrobenzamide mustard is activated by reduction to hydroxylamine (PR-104H) and amine (PR-104M) metabolites selectively in hypoxic cells, and also independently of hypoxia by aldo-keto reductase (AKR) 1C3 in some tumors. Here, we evaluate reductive metabolism of PR-104A in mice and its significance for host toxicity. Methods The pharmacokinetics of PR-104, PR-104A and its reduced metabolites were investigated in plasma and tissues of mice (with and without SiHa or H460 tumor xenografts) and effects of potential oxidoreductase inhibitors were evaluated. Results Pharmacokinetic studies identified extensive non-tumor reduction of PR-104A to t...

2011-01-01

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Enzymatic mechanism in low chloride media: influence of glucose oxidase on the electrochemical behaviour of AISI 316L stainless steel; Mecanisme enzymatique en milieux faiblement chlorures: influence de la glucose oxydase sur le comportement electrochimique de l'acier inoxydable AISI 316L  

Energy Technology Data Exchange (ETDEWEB)

The open circuit potential (OCP) of stainless steels immersed in natural waters generally increases with time. This phenomenon is strongly linked to the formation of a bio-film on the surface. Several studies have proved that the bio-film modifies the reaction of reduction of dissolved oxygen and that it acts mainly on the cathodic processes. One of the hypotheses explaining the action of the bio-film involves certain bacteria which use dissolved oxygen and extracellular enzymes to produce reactive oxygen species. Among this kind of metabolites is hydrogen peroxide H{sub 2}O{sub 2}. This compound interacts with the passive layer of stainless steels and affects their electrochemical behaviour, even when the chloride concentration is low. The aim of this work is to study the influence of an enzymatic reaction (of the oxidoreductase type) on anodic and cathodic processes on AISI 316L stainless steel. Experiments are carried out in two artificial electrolytes ...

2006-07-01

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Strain differences in the responsiveness between Sprague-Dawley and Fischer rats to nephropathy induced by FYX-051, a xanthine oxidoreductase inhibitor  

International Nuclear Information System (INIS)

To determine a rat strain appropriate for carcinogenicity testing of FYX-051, a xanthine oxidoreductase inhibitor, we performed a 4-week oral toxicity study by administering 0.3, 1 and 3 mg/kg, and 1, 3 and 10 mg/kg of FYX-051 to male Sprague-Dawley (SD) and Fischer (F344) rats, respectively. Histopathology revealed that the degree of FYX-051-induced nephropathy was 3-fold stronger in SD rats than in F344 rats. Our previous study demonstrated that the key factor of species differences in FYX-051-induced nephropathy is purine metabolism. This observation led us to examine the involvement of purine metabolism in differences among two strains of rats. However, purine metabolism was proven not to be implicated as an important factor. Subsequently, other factors responsible for the strain differences were examined. FYX-051-induced increases in plasma xanthine concentrations were higher in SD rats than in F344 rats, suggesting more remarkable effects on pharmacodynamics ...

2006-12-15

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Unraveling photosystems. Final technical report  

Energy Technology Data Exchange (ETDEWEB)

This report highlights four main points. (1) A residue substitution in phosphoribulokinase of Synechocystis PCC 6803 renders the mutant light-sensitive. The authors isolated a light-sensitive mutant (BRLS) of the photosynthetic cyanobacterium Synechocystis 6803 that does not survive exposure to bright light; 70% of BRLS cells die upon exposure to light of > 3000 lux for 2 hr. (2) Excitation energy transfer from phycocyanin to chlorophyll in an apcA-defective mutant of Synechocystis sp. PCC 6803. A greenish mutant of the normally bule-green cyanobacterium Synechocystis sp. PC 6803, designated UV6p, was isolated and characterized. UV6p possesses functional photosystems I and II but lacks normal light harvesting phycobilisomes because allophycocyanin is absent and core-specific linker proteins are almost entirely absent. (3) Deletion of the psbG1 gene of the cyanobacterium Synechocystis sp. PCC 6803 leads to the activation of the cryptic psbG2 gene. The genes psbG1 and psbG2 in ...

1997-09-01

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Chemopreventive effects of Furan-2-yl-3-pyridin-2-yl-propenone against 7,12-dimethylbenz[a]anthracene-inducible genotoxicity  

International Nuclear Information System (INIS)

1-Furan-2-yl-3-pyridin-2-yl-propenone (FPP-3) is an anti-inflammatory agent with a propenone moiety and chemically synthesized recently. In this study, we examined the chemopreventive effect of FPP-3 on 7,12-dimethylbenz[a]anthracene (DMBA)-induced genotoxicity in MCF-7 cells. FPP-3 reduced the formation of the DMBA-DNA adduct. DMBA-induced CYP1A1 and CYP1B1 gene expression and enzyme activity were inhibited by FPP-3. It inhibited DMBA-induced aryl hydrocarbon receptor (AhR) transactivation and DMBA-inducible nuclear localization of the AhR. Induction of detoxifying phase II genes by chemopreventive agents represents a coordinated protective response against oxidative stress and neoplastic effects of carcinogens. Transcription factor NF-E2 related factor 2 (Nrf2) regulates antioxidant response element (ARE) of phase II detoxifying and antioxidant enzymes, such as glutathione S-transferase (GST) and NAD(P)H:quinone oxidoreductase (QR). FPP-3 increased the expression ...

2008-05-01