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)

A clone of DNA, obtained from the luminescent bacterium Vibrio fischeri ATCC 7744 and inserted into pBR322, was found to express luminescence in Escherichia coli. Polypeptides involved in biosynthesis of the fatty aldehyde substrate for the light reaction were identified by fatty acid acylation of proteins synthesized in E. coli from the recombinant plasmid. The cloned region was similar to that reported for the V. fischeri MJ1 luminescence system (Engebrecht et al., Cell 32:773-781), except for some differences in endonuclease restriction sites and the requirement of a lower temperature for the expression of light in our cloned system. Fatty acid reductase activity could be detected in extracts of E. coli harboring the recombinant plasmid but not in extracts of the parental V. fischeri strain. Using in vivo labeling with [3H]tetradecanoic acid, we showed that the acylated polypeptides synthesized in the cloned system corresponded to the labeled polypeptides in V. fischeri (34, 42, and 54 kilodaltons) and that they could only be detected after induction of luminescence. These results provide direct evidence that the genes coding for the fatty acid reductase polypeptides are an integral part of the luminescence operon in the V. fischeri luminescence system.
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PMID:Functional identification of the fatty acid reductase components encoded in the luminescence operon of Vibrio fischeri. 299 37

The organization of the lux structural genes (A-E) in Photobacterium phosphoreum has been determined and a new gene designated as luxF discovered. The P. phosphoreum luminescence system was cloned into Escherichia coli using a pBR322 vector and identified by cross-hybridization with Vibrio fischeri lux DNA. The lux genes were located by specific expression of P. phosphoreum DNA fragments in the T7-phage polymerase/promoter system in E. coli and identification of the labeled polypeptide products. The luxA and luxB gene products (luciferase subunits) were shown to catalyze light emission in the presence of FMNH2, O2, and aldehyde. The luxC, luxD, and luxE gene products (fatty acid reductase subunits) responsible for aldehyde biosynthesis could be specifically acylated with 3H-labeled fatty acids. The order of the lux genes in P. phosphoreum was found to be luxCDABFE with luxF coding for a new polypeptide of 26 kDa. The presence of a new gene in the P. phosphoreum luminescence system between luxB and luxE as compared to the organization of the lux structural gene in V. fischeri and Vibrio harveyi (luxCDABE) demonstrates that the luminescent systems in the marine bacteria have significantly diverged. The discovery of the luxF gene provides the basis for elucidating the role of its gene product in the expression of luminescence in different marine bacteria.
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PMID:Cloning and expression of the Photobacterium phosphoreum luminescence system demonstrates a unique lux gene organization. 304 75

Pyridoxine dehydrogenase (1.1.1.65) (pyridoxal reductase), purified to homogeneity from baker's yeast, is a monomer of Mr approximately 33,000. It catalyzes the reversible oxidation of pyridoxine by NADP to yield pyridoxal and NADPH; equilibrium lies far in the direction of pyridoxine formation (Keq approximately 1.4 X 10(11) l/mol at 25 degrees C). Reduction of pyridoxal occurs most rapidly at pH 6.0-7.0; oxidation of pyridoxine is optimal at pH 8.6. NAD and NADH do not replace NADP and NADPH as substrates; pyridoxine, pyridoxal and pyridoxal 5'-phosphate are the only naturally occurring cosubstrates found. Several other aromatic aldehydes also are reduced, but substrate specificity and other properties of the enzyme distinguish it clearly from other alcohol dehydrogenases or aldehyde reductases. Between pH 6.3 and 7.1 (the intracellular pH of yeast), V/Km with pyridoxal and NADPH as substrates is greater than 600 times that observed with pyridoxine and NADPH as substrates is greater than 600 times that observed with pyridoxine and NADP as substrates. These and other considerations strongly indicate that the dehydrogenase functions in vivo to reduce pyridoxal to pyridoxine, which is the preferred substrate for pyridoxal (pyridoxine) kinase in yeast.
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PMID:Physical and kinetic properties of a pyridoxal reductase purified from bakers' yeast. 307 41

The aldehyde reductases comprise a group of monomeric NADPH-dependent oxidoreductases with a broad and similar substrate specificity. Three major reductases, ALR1, ALR2, and ALR3, occur in tissues. The predominant one, ALR1, is aldehyde reductase; ALR2 is aldose reductase, an enzyme implicated in the etiology of diabetic complications; and ALR3 is carbonyl reductase, the only reductase with any affinity for ketones. ALR1 and ALR2 are immunologically nonrelated, and little immunologic relatedness exists between aldehyde reductases, particularly ALR1, from different species. The evolutionary relatedness of ALR2, however, may be closer, particularly among the primates. ALR2 from human and monkey tissues are immunologically identical.
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PMID:Aldose and aldehyde reductase in animal tissues. 308

alpha, beta-Unsaturated aldehydes are reactive and cytotoxic compounds which occur in the environment and are also formed in vivo. Many of these aldehydes have been reported to inhibit hepatic cytochrome P-450. Our laboratory has shown that trans,trans-muconaldehyde (a possible metabolite of benzene) as well as acrolein and crotonaldehyde, when added to hepatic microsomes, decreased cytochrome P-450 (measured spectrophotometrically). Additional studies showed that several alpha, beta-unsaturated aldehydes also inhibited hepatic microsomal NADPH-cytochrome c reductase. Acrolein, crotonaldehyde and trans,trans-muconaldehyde all decreased NADPH-cytochrome c reductase activity in vitro. Concentrations of 0.5, 1.0 and 1.5 mM acrolein decreased activity to 60, 26 and 11% of control respectively. Similar concentrations of trans,trans-muconaldehyde inhibited NADPH-cytochrome c reductase. Crotonaldehyde was a less effective inhibitor of this enzyme. Propionaldehyde, a saturated aldehyde, had no effect on NADPH-cytochrome c reductase activity. Time course experiments with acrolein over a period of 5-45 min suggest that the loss of NADPH-cytochrome c reductase activity is non-linear. The addition of reduced glutathione protected against the inhibition of reductase activity by acrolein. Formation of these aldehydes and their subsequent inhibition of these enzymes may have important consequences in xenobiotic metabolism.
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PMID:Inhibition of microsomal cytochrome c reductase activity by a series of alpha, beta-unsaturated aldehydes. 310 27

Enoate reductase or clostridia containing this enzyme (Clostridium tyrobutyricum or C. kluyveri) catalyse the reduction of alpha,beta-unsaturated aldehydes (enals). The enantiomeric purity of the saturated aldehydes obtained from alpha-substituted enals is usually rather low and depends heavily on the reaction conditions. The reduction of the corresponding allyl alcohols to the saturated alcohols leads to much higher enantiomeric purities, though the reduction of the enal corresponding to the allyl alcohol to the saturated aldehyde is an intermediary step in the reaction sequence allyl alcohol----saturated alcohol. The explanation seems to be the racemisation of saturated aldehydes caused by enoate reductase. This is illustrated by the reduction of (E)-2-methylcinnamyl aldehyde to (R)-2-methyl-3-phenylpropanal or (R)-2-methyl-3-phenylpropanol under different conditions and measuring the racemisation of the aldehyde as well as the hydrogen-deuterium exchange of 3-phenylpropanal. In contrast to saturated carboxylates saturated aldehydes can be dehydrogenated to alpha,beta-unsaturated aldehydes (enals) by enoate reductase in the presence of electron acceptors such as oxygen or dichlorophenol indophenol. Under these conditions enoate reductase shows in the presence of oxygen a surprisingly high half life (greater than 20 h) as compared to that which is observed when the enzyme was used as a reductase with NADH in the presence of oxygen. In this case the enzyme is inactivated within a few minutes.
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PMID:Reductions of 2-enals, dehydrogenation of saturated aldehydes and their racemisation. 320 53

The nucleotide sequence of the luxC gene (1431 bp) and the upstream DNA (1049 bp) of the luminescent bacterium Vibrio harveyi has been determined. The luxC gene can be translated into a polypeptide of 55 kDa in excellent agreement with the molecular mass of the reductase polypeptide required for synthesis of the aldehyde substrate for the bioluminescent reaction. Analyses of codon usage showed a high frequency (1.9%) of the isoleucine codon, AUA, in the luxC gene compared to that found in Escherichia coli genes (0.2%) and its absence in the luxA, B and D genes. The low G/C content of the luxC gene and upstream DNA (38-39%) compared to that found in the other lux genes of V. harveyi (45%) was primarily due to a stretch of 500 nucleotides with only a 24% G/C content, extending from 200 bp inside lux C to 300 bp upstream. Moreover, an open reading frame did not extend for more than 48 codons between the luxC gene and 600 bp upstream at which point a gene transcribed in the opposite direction started. As the lux system in the luminescent bacterium, V. fischeri, contains a regulatory gene immediately upstream of luxC transcribed in the same direction, these results show that the organization and regulation of the lux genes have diverged in different luminescent bacteria.
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PMID:Nucleotide sequence of the LuxC gene and the upstream DNA from the bioluminescent system of Vibrio harveyi. 334 97

We have developed a high performance thin layer chromatography (HPTLC) system for quantitative determination of androgens, corticosteroids, mineralocorticoids and gestagens on silicagel KG-60 HPTLC-plates with different solvent systems. A complete separation of androgens, gestagens and metabolites was achieved with dichlormethane/cyclohexane/acetone (70:25:5). Corticosteroids, mineralocorticoids and their derivatives were completely separated with diethylether/isooctane/isopropanol (70:25:5). The quantitative in situ fluorescence determination was carried out after post-chromatographic derivatization with cinnamic aldehyde, 4-dimethylaminobenzaldehyde and sulfuric acid. The sensitivity of detection was found between 500 pg and 1 ng per spot. The steroid metabolism as catalysed by rat liver microsomal oxidoreductases was measured by these procedures, and was compared with determination of steroids by gas chromatography (GC). According to HPTLC, steroids were reduced by NADPH-5 alpha-reductase (EC 1.3.1.4) in the order progesterone greater than testosterone greater than aldosterone greater than cortisol greater than corticosterone. The enzyme activities as measured by HPTLC agree well with those obtained by GC (r = 0.94). When turnover of enzyme assays, speed of determination, detection limit, application to labile steroids and costs of steroid determination are considered, all points speak in favour of HPTLC.
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PMID:Thin-layer chromatography--the forgotten alternative for the quantitative determination of steroids. 350 34

We developed three daunorubicin (D1)-resistant sublines (ML1/I, II, III) from the human myelocytic cell line (ML1). These sublines were 28-, 70- and 162-fold more resistant than sensitive (ML1/S) cells to the cytotoxicity of D1 and were cross-resistant to adriamycin, epiadriamycin, actinomycin D, VP-16, VM26, and mitoxantrone. Steady-state levels of D1 in resistant sublines I and II, in the presence or absence of azide, were not significantly different from those of sensitive cells. However, the steady-state level of D1 in subline III was significantly increased in the presence of sodium azide. D1 efflux was minimal in ML1/S and resistant cells in the absenced of glucose. Addition of glucose enhanced D1 efflux only in subline III. Verapamil increased the cellular levels of D1 and inhibited its efflux from resistant III cells but not from ML1/S cells. Verapamil also greatly enhanced the cytotoxicity of D1 for sublines I, II, and III. The differences between sensitive and resistant cells in D1 uptake and retention seemed inadequate to cause 162-fold resistance and suggested other factors may be contributing to the development of resistance. In support of this hypothesis, daunorubicin reductase activity was significantly lower in resistant cells than in ML1/S cells. The greatest decrease in activity occurred at pH 8.5 which represents aldehyde reductases. Currently, we are investigating other possibilities for D1 metabolism, such as aglycone and free radical formation.
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PMID:Contribution of drug transport and reductases to daunorubicin resistance in human myelocytic cells. 353 83

When isogenic strains of Escherichia coli, RR1 (rec+) and HB101 (recA), were transformed with mapped recombinant plasmids known to contain Vibrio harveyi luciferase genes and large regions of DNA flanking on both sides, a small percentage (0.005%) of the colonies expressed high levels of luminescence (up to 10(12) quanta s-1 ml-1) in the absence of added aldehyde. The altered ability to express light was found to be due to a mutation in the host and not to an alteration in the recombinant DNA. When these bright colonies were cured of plasmid, they could be retransformed with cloned V. harveyi gene fragments in cis and in trans to yield luminescent colonies at 100% frequency. The maximum length of V. harveyi DNA required to produce light-emitting E. coli was shorter (6.3 kilobase pairs) than that required for expression of the V. fischeri system in E. coli. Cell extracts from bright clones contained wild-type levels of activity for the heteropolymeric (alpha beta) luciferase; fatty acid labeling revealed the presence of the three acylated polypeptides of the fatty acid reductase system which is involved in aldehyde biosynthesis for the luminescence reaction. The increased light emission in the mutant bacteria appeared to arise in part from production of higher levels of polycistronic mRNAs coding for luciferase.
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PMID:Expression of bioluminescence by Escherichia coli containing recombinant Vibrio harveyi DNA. 353 17


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