Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The HM1 gene in maize controls both race-specific resistance to the fungus Cochliobolus carbonum race 1 and expression of the NADPH (reduced form of nicotinamide adenine dinucleotide phosphate)-dependent HC toxin reductase (HCTR), which inactivates HC toxin, a cyclic tetrapeptide produced by the fungus to permit infection. Several HM1 alleles were generated and cloned by transposon-induced mutagenesis. The sequence of wild-type HM1 shares homology with dihydroflavonol-4-reductase genes from maize, petunia, and snap-dragon. Sequence homology is greatest in the beta alpha beta-dinucleotide binding fold that is conserved among NADPH- and NADH (reduced form of nicotinamide adenine dinucleotide)-dependent reductases and dehydrogenases. This indicates that HM1 encodes HCTR.
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PMID:Reductase activity encoded by the HM1 disease resistance gene in maize. 135 42

Saccharomyces cerevisiae catalyses the asymmetric reductive biotransformation of a variety of compounds containing a carbonyl group or carbon-carbon double bond. Oxidoreductases participating in these reactions which have commercial potential in biotransformation processes are likely to have relatively broad substrate specificity. Important carbonyl reductases falling into this category include YADH- and yeast NADP-dependent beta-ketoester reductases. The enoyl reductase component of the FAS complex may have a role in asymmetric yeast reduction of carbon-carbon double bonds of unnatural substrates. Other nicotinamide-requiring oxidoreductases of yeast are also surveyed to rationalize observed biotransformations of whole yeast cells in terms of specific enzymes. Genetic and protein engineering may enable enzymes to be tailored to accept new substrates. A greater understanding of the enzymes and reactions involved will facilitate further optimization and exploitation of these catalytic systems in industrial processes.
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PMID:Reductive biotransformations of organic compounds by cells or enzymes of yeast. 136 32

NADH was metabolized both by serum components and at the cell surface. The metabolism by serum was either oxidation to NAD+, or hydrolysis of the pyrophosphate to yield nicotinamide mononucleotide (reduced) (NMNH) and AMP. NMNH was further hydrolysed to yield nicotinamide riboside (reduced) (NRH), which was stable. NAD+ was hydrolysed (although at a slower rate than was NADH), but was also reduced to yield NADH. The reduction of NAD+ was catalysed by the enzyme serum L(+)lactate dehydrogenase (EC 1.1.1.27) and was dependent on the concentration of L(+)lactate in the serum. NADPH was hydrolysed in a similar manner to NADH but not oxidized by serum. NADH generated from NAD+ by serum derived from human, foetal calf and horse sources was capable of driving the bioreductive activation of CB 1954 by the enzyme DT diaphorase. Cell surfaces oxidized NADH to NAD+, but did not oxidize NADPH or NRH. These observations suggest that NAD(P)H would be unsuitable as a source of reducing equivalents for the bioreductive activation of prodrugs by a reductase enzyme in Antibody Directed Enzyme Prodrug Therapy (ADEPT). In contrast, NAD+ (which could act as a source of NADH) and NRH could avoid the shortcomings of NAD(P)H, and act as suitable cofactors for an enzyme in an ADEPT system.
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PMID:Metabolism of NAD(P)H by blood components. Relevance to bioreductively activated prodrugs in a targeted enzyme therapy system. 138 14

An expression vector for bovine NADH-cytochrome b5 reductase was used for site-directed mutagenesis of lysine 110, the residue previously implicated in NADH interactions with this flavoprotein. Replacement of this basic residue with an uncharged glutamine resulted in an increase of 3 orders of magnitude in the Km for NADH and a decrease in kcat of an order of magnitude, strongly implicating lysine 110 in both binding of NADH to the reductase and the orientation of the reduced nicotinamide group for rapid hydride ion transfer to the flavin. Substitution of lysine 110 by histidine, to provide a pH-sensitive positive charge at this position in the neutral pH range, exhibited only a moderate 25-fold increase in Km and a normal kcat at pH 6.0, whereas at pH 8.5 the Km for NADH rose to 238 microM with a decrease of 45% over unmodified enzyme in the kcat. A similar pH sensitivity in the inhibition constant for adenosine diphosphate ribose, lacking only the nicotinamide moiety of NADH, emphasizes the crucial role of the positive charge at this locus and is consistent with charge-pairing of lysine 110 with the pyrophosphate group of NADH or adenosine diphosphate ribose.
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PMID:Characterization of the role of lysine 110 of NADH-cytochrome b5 reductase in the binding and oxidation of NADH by site-directed mutagenesis. 140 Mar 35

The purpose of this study was to define variability of the oxidative capacity and glycogen content between different fiber types and regions of the hamster diaphragm. Using histochemical and microphotometric techniques, the oxidative capacity (identified by nicotinamide-adenine dinucleotide tetrazolium reductase reaction end product) and glycogen levels (identified by the periodic acid-Schiff stain test) were examined in three myofibrillar ATPase (M-ATPase) fiber types and four diaphragmatic regions: sternal, anterior costal, thoracic surface of the crural (thor/crur), and abdominal surface of the crural (abd/crur). Most regional differences were found between the crus and the rest of the diaphragm. There were no differences in the oxidative capacity between diaphragmatic regions in the types 1 and 2a fibers, but the type 2b fibers in the thor/crur region had the greatest oxidative capacity and the 2b fiber in the sternal region had the lowest oxidative capacity. There were differences in glycogen content between diaphragmatic regions for all of the three M-ATPase fiber types. Variability in oxidative capacity between fiber types was demonstrated in all regions except the thor/crur region. Variation in glycogen content between fiber types was only demonstrated in the two surfaces of the crus. The type 2b fiber demonstrated the most differences from types 1 and 2a fibers in oxidative capacity and glycogen content in the different diaphragmatic regions, whereas the types 1 and 2a fibers demonstrated few differences from each other in these features across the different diaphragmatic regions.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fiber type and regional differences in oxidative capacity and glycogen content in the hamster diaphragm. 144 83

The effect of selenium administered acutely or chronically on the hepatic microsomal drug-metabolizing system has been investigated in mice. After 72 h following acute administration of selenium (7.5 mg/kg, i.p.), there was a significant inhibition of the activities of aminopyrine (AM) N-demethylase and ethylmorphine (EM) N-demethylase, and cytochrome P-450 levels but no change in the activities of aniline (AN) hydroxylase, 7-ethoxycoumarin (EC) O-deethylase, reduced nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome c reductase and reduced nicotinamide adenine dinucleotide (NADH)-ferricyanide reductase, and cytochrome b5 content. Chronic administration of selenium in the drinking water (1 or 2 ppm selenium) for 12 weeks, resulted in no alteration in any of the parameters measured. However, significant decreases in activities of AM N-demethylase and AN hydroxylase, and cytochrome P-450 levels were detected in animals given higher doses of selenium (4 or 8 ppm selenium). Following the in vitro additions of selenium to hepatic microsomes obtained from untreated mice, selenium inhibited the AM N-demethylase, AN hydroxylase and 7-EC O-deethylase in a concentration-dependent manner, but no alteration in NADPH-cytochrome c reductase and cytochrome P-450 levels was observed. These results indicate that selenium is a specific from inhibitor of hepatic monooxygenase.
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PMID:Inhibition of hepatic mixed-function oxidase enzymes in mice by acute and chronic treatment with selenium. 147 37

In order to distinguish the pathways involved in the oxidation of matrix NADH in plant mitochondria, the oxidation of NADH and nicotinamide hypoxanthine dinucleotide (reduced form) was investigated in submitochondrial particles prepared from beetroot (Beta vulgaris L. cv. Derwent Globe) and soybeans (Glycine max L. cv. Bragg). Nicotinamide-hypoxanthine-dinucleotide(reduced form)-oxidase activity was more strongly inhibited by rotenone than the NADH-oxidase activity but both of the rotenone-inhibited activities could be stimulated by adding ubiquinone-1. The corresponding ubiquinone-1-reductase activities were inhibited by rotenone (to 69%) and further inhibited by N,N'-dicyclohexylcarbodiimide (to 79%), whilst the K3Fe(CN)6-reductase activities were not sensitive to either rotenone or N,N'-dicyclohexylcarbodiimide. Immunological analysis of mitochondrial proteins using an antiserum raised against purified beetroot complex I indicated very few differences between soybean and fresh and aged beetroot mitochondria, despite their varying sensitivities to rotenone. We confirm that there are two dehydrogenases capable of oxidising internal NADH and that only one of these, namely complex I, is inhibited by rotenone. Further, we conclude that complex I has two potential sites of quinone reduction, both sensitive to N,N'-dicyclohexycarbodiimide inhibition but only one of which is sensitive to rotenone inhibition.
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PMID:Matrix NADH dehydrogenases of plant mitochondria and sites of quinone reduction by complex I. 152 39

The etiology of idiopathic dilated cardiomyopathy (DCM) is yet unknown; this study aimed at further differentiation of the disease by means of enzyme histochemistry. Endomyocardial biopsies from the left ventricle of 40 DCM patients and 5 control specimens had enzymes examined histochemically and semiquantitatively and analyzed according to staining intensities of nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR), succinate dehydrogenase, cytochrome c oxidase, lactate dehydrogenase and acid phosphatase (aPh). In DCM, the NADH-TR activity was elevated as compared to controls, indicating impaired mitochondrial oxidative phosphorylation. However, a concrete relation of enzyme histochemical intensity to anamnestic, hemodynamic or histomorphometric data could not be determined, except for the fact that the intensity of the lysosomal enzyme aPh was elevated in DCM patients with a relatively high left ventricular ejection fraction. The results demonstrate an interindependence of structural, hemodynamic and historical parameters as well as enzyme concentrations in DCM. Thus, a pathological change in the enzyme concentrations tested here cannot be responsible for the functional myocardial impairment in DCM.
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PMID:Enzyme histochemistry of endomyocardial biopsies in idiopathic dilated cardiomyopathy. 165 Nov 62

A staining procedure used for simultaneously determining three different fiber types in single sections of bovine, porcine, or ovine skeletal muscle was modified for use with broiler skeletal muscle. The modification involved acid-preincubation of muscle sections at a pH of 4.15 followed by staining for reduced nicotinamide adenine dinucleotide (NADH) tetrazolium reductase enzyme and for acid-stable myosin-adenosine triphosphatase enzyme activity, respectively. Four broiler muscles were selected for fiber-type determination of fast (alpha), slow (beta), red, aerobic (R), or white, anaerobic (W) properties. The anterior latissimus dorsi muscle was composed almost entirely of beta-R fibers while the pectoralis superficialis muscle was composed almost entirely of alpha-W fibers. The sartorius and posterior latissimus dorsi muscles were much more heterogeneous in fiber-type distribution, exhibiting all three types of fibers (alpha-W, alpha-R, and beta-R).
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PMID:Research note: simultaneous histochemical determination of three fiber types in single sections of broiler skeletal muscles. 170 Apr 8

Various different combinations of histochemical stains at differing pH levels on single sections of bovine skeletal muscle were evaluated. The staining sequence that was the most consistent and reliable of those studied included an initial NADH-TR (reduced nicotinamide adenine dinucleotide-tetrazolium reductase) followed by an acid ATPase stain at pH 4.15. This staining combination resulted in easily discernable type I, II A, and II myofibers. Thus, a marked saving of expended time, labor and materials was realized.
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PMID:A rapid and reliable sequential staining method for bovine muscle. 170 Jun 44


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