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

A particulate fraction prepared from Mycobacterium phlei grown in a metal-deficient medium exhibited a greatly reduced activity of stearoyl-CoA desaturase compared to that from normally grown cells. Metal deficiency, however, had no effect on the FAD-dependent NADPH-cytochrome C reductase activity, which has been suggested to participate in the desaturation process. When the cells were grown in the deficient medium supplemented with both Fe2+ and Mg2+, the desaturase activity was restored to the normal level. Supplementation with Mg2+ alone promoted growth but did not restore the desaturase activity, whereas Fe2+ alone did cause a significant restoration. Among the various metal ions tested, only Fe2+ and Fe3+ enhanced the formation of desaturase activity in the deficient medium. When added to the assay medium in vitro, Fe2+ and Fe3+ did not stimulate the desaturase activity of the particulate fraction from the deficient cells. Cultivation in the metal-deficient medium had essentially no effect on the levels of cytochromes in the particulate fraction, but dramatically decreased the non-heme iron content and the amount of a high-spin ferric species exhibiting an ESR signal at g=4.3. No labile sulfur could be detected in the normal or metal-deficient particulate fractions. It is concluded that the presence of iron ions in the culture medium is necessary for the synthesis and/or assembly of the terminal portion of the desaturase system.
 ...
PMID:Effect of metal ions in the culture medium on the stearoyl-coenzyme A desaturase activity of Mycobacterium phlei. 0 87

In a continuing study of the biosynthetic pathway and regulatory mechanisms governing indole-3-acetic acid (auxin) formation, we report the isolation and initial characterization of three distinct indole-3-acetaldehyde reductases from cucumber seedlings. These enzymes catalyze the reduction of indole-3-acetaldehyde to indole-3-ethanol with the concomitant oxidation of NAD(P)H to NAD(P)+. Two of the reductases are specific for NADPH as second substrate, while the third is specific for NADH. The enzymes show a strong specificity for indoleacetaldehyde, with apparent Km values of 73mum, 130mum, and 400mum being calculated for the two NADPH-specific reductases and the NADH-specific reductase, respectively. Under no conditions of substrate concentration, incubation time, or assay method could the reverse reaction be observed. Chromatography on a calibrated Sephadex gel column led to estimated molecualr weights of 52,000 and 17,000 for the NADPH-specific reductases, while a value of 33,000 was obtained for the NADH-specific reductase. Both NADPH-specific reductases showed a pH optimum of 5.2 with a secondary optimum at 7.0, and both enzymes were activated by increasing ionic strength. The NADH-specific reductase showed a pH optimum of 7.0 with a secondary optimum at 6.1 and was slightly inhibited by increasing ionic strength.
 ...
PMID:Isolation and characterization of indole-3-acetaldehyde reductases from Cucumis sativus. 0 7

Regional distributions of PGE 9-ketoreductase and 15-hydroxy-prostaglandin dehydrogenase were examined in the cytoplasmic fractions from the kidneys of seven species. All species contained an NADPH-dependent reductase, as well as NAD+- and NADP+-dependent dehydrogenases in both cortex and medulla. A previously unrecognized cytoplasmic NADH-dependent PGE 9-ketoreductase was also detected in the cortex and medulla of rat and bovine kidney. Total NAD+- and NADP+-dependent dehydrogenase activity was about equally distributed between the two renal regions of monkey, dog, rat, and swine. Bovine, rabbit, and cat had greater cortical than medullary dehydrogenase activity with ratios of 3, 5, and 10 respectively. The activities of NAD+- and NADP+-dependent dehydrogenase varied among the renal tissues.
 ...
PMID:Distribution of prostaglandin E 9-ketoreductase and NAD+-dependent and NADP+-dependent 15-hydroxyprostaglandin dehydrogenase in the renal cortex and medulla of various species. 0 61

The enzymatic reactions are described by which delta4-3-oxosteroids, specially testosterone, are inactivated in rat liver. The delta4-3-oxosteroid-5 alpha-reductase in liver microsomes was studied intensively and it was found that it is an enzyme system. The 5 alpha-reduction of testosterone with NADPH or with NADH depends upon different enzymes or enzyme systems.
 ...
PMID:[The metabolism of delta4-3-oxosteroids in rat liver]. 0 39

NADH and NADPH-ferredoxin oxidoreductases have been studied in Clostridium acetobutylicum, Cl. tyrobutyricum and Cl. pasteurianum. The study of the distribution and regulation of these enzymatic activities in well-defined culture conditions, reveals that the essential function of NADPH-ferredoxin oxidoreductase is to produce NADPH, while NADH-ferredoxin oxidoreductase can, depending on cellular conditions, produce or oxidize NADH. When these Clostridia use glycolysis, regulation of the NADH-ferredoxin oxidoreductase by acetyl-CoA (obligatory activator of NADH-ferroxin reductase activity) and by NADH (competitive inhibitor of ferredoxin-NAD+ reductase activity) allow the enzymes to function correlatively with glyceraldehyde-3-phosphate dehydrogenase and thus control the levels of NAD+ and NADH in the cell. In Cl. tyrobutyricum and Cl. pasteurianum, the ferredoxin-NADP+ reductase activities are regulated by NAD+ and NADH in accordance with the intracellular concentrations of these coenzymes. In Cl. tyrobutyricum growing on pyruvate/acetate, NADH and NADPH-ferredoxin reductase activities cannot be detected; only the ferredoxin-NAD+ and ferredoxin-NADP+ reductase activities are found. In this Clostridium, regulation of the ferredoxin-NADP+ reductase activity is the same whether it is grown on glucose or pyruvate. Contrary to this, the ferredoxin-NAD+ reductase activity undergoes a drastic change, since NADH no longer controls the enzymatic activity. In this case regulation is no longer necessary, since glyceraldehyde-3-phosphate dehydrogenase does not function.
 ...
PMID:Regulation of the NADH and NADPH-ferredoxin oxidoreductases in clostridia of the butyric group. 0 18

Pediococcus cerevisiae/AMr, resistant to amethopterin, possesses a higher dihydrofolate reductase (5, 6, 7, 8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) activity than the parent, a folate-permeable and thus amethopterin-susceptible strain and than the wild-type. The properties of dihydrofolate reductase from the three strains have been compared. Temperature, pH optima, heat stability, as well amethopterin binding did not reveal significant differences between the enzymes from the susceptible and resistant strains. The enzyme from the wild-type was 10 times more sensitive to inhibition by amethopterin and more susceptible to heat denaturation. The apparent Km values for dihydrofolate in enzymes from the three strains were in the range of 4.8--7.2 muM and for NADPH 6.5--8.0 muM. The amethopterin-resistant strain exhibited cross-resistance to trimethoprim and was about 40-fold more resistant to the latter than the sensitive parent and the wild-type. The resistance to trimethoprim appears to be a direct result of the increased dihydrofolate reductase activity. Inhibition of dihydrofolate reductase activity by this drug was similar in the three strains. 10--20 nmol caused 50% inhibition of 0.02 enzyme unit. Trimethoprim was about 10 000 times less effective inhibitor of dihydrofolate reductase than amethopterin. The cell extract of the AMr strain possessed a folate reductase activity three times higher than that of the sensitive strain. The activities of other folate-related enzymes like thymidylate synthetase and 10-formyltetrahydrofolate synthetase (formate: tetrahydrofolate ligase (ADP-forming), EC 6.3.4.3) were similar in the three strains studied.
 ...
PMID:Resistance of Pediococcus cerevisiae to amethopterin as a consequence of changes in enzymatic activity and cell permeability. I. Dihydrofolate reductase, thymidylate synthetase and formyltetrahydrofolate synthetase in amethopterin-resistant and -sensitive strains of Pediococcus cerevisiae. 0 54

Non-enzymatic formation of dipicolinic acid (DPA) from diketopimelic acid and ammonia was clearly demonstrated using a new method for DPA analysis. The reaction rates of DPA formation were almost the same under aerobic and anaerobic conditions. Nearly equimolecular quantities of DPA and tetrahydrodipicolinic acid were detected in spontaneous reaction mixture. The spontaneous reaction seemed to be due to dismutation of dihydrodipicolinic acid, resulting in DPA and tetrahydrodipicolinic acid. The apparent optimum pH of the spontaneous reaction was 8.2 and the maximal rate of DPA formation was observed with a 1 : 4 molar ratio of diketopimelic acid to ammonia. The rate of the spontaneous reaction was stimulated by ferrous sulfate, FMN, and riboflavin. Dihydrodipicolinate reductase catalyzes the reduction of dihydrodipicolinate, prepared from pyruvate and aspartic beta-semialdehyde, with NADPH as reductant. The reductase was isolated from Bacillus subtilis, and found to stimulate DPA formation from diketopimelic acid and ammonia. The enzymatic DPA formation was absolutely dependent on oxygen, and optimum pH was 6.4. The catalytic action of the enzyme was similar to that of the oxidase. Possible mechanisms of DPA formation from diketopimelic acid and ammonia are proposed.
 ...
PMID:Pyridine-2, 6-dicarboxylic acid (dipicolinic acid) formation in Bacillus subtilis. II Non-enzymatic and enzymatic formations of dipicolinic acid from alpha, epsilon-diketopimelic acid and ammonia. 0 41

Changes in the ultraviolet/visible spectrum of human oxyferrohemoglobin upon addition of aniline were indicative of a concentration-dependent interaction of aniline with hemoglobin, resulting in accelerated autooxidation of the hemoprotein. Oxygen was found to markedly inhibit this interaction of aniline with oxyhemoglobin. The dependence of the rate of autooxidation on aniline concentration followed saturation kinetics and showed a half-maximal response at 8 mM aniline. This value is equal to the value of Km for aniline as substrate for the O2-dependent, hemoglobin-catalyzed hydroxylation reaction which yields p-aminophenol (Mieyal, J. J., Ackerman, R.S., Blumer, J.L., and Freeman, L.S. (1976) J. Biol. Chem. 241, 3436-3441). Thus, an aniline-oxyhemoglobin complex is implicated in the overall catalytic reaction. No detectable p-aminophenol was formed when aniline was combined with oxyhemoglobin in the absence of an electron donor, but hydroxylation of aniline does occur when NADPH, NADPH plus P-450 reductase, or Na2S2O4 are also added.
 ...
PMID:Accleration of autooxidation of human oxyhemoglobin by aniline and its relation to hemoglobin-catalyzed aniline hydroxylation. 0 53

A cinnamoyl-coenzyme A reductase catalyzing the NADPH-dependent reduction of substituted cinnamoyl-CoA thiol esters to the corresponding cinnamaldehydes was isolated from cell suspension cultures of soybean (Glycine max L. var. Mandarin). A 1660-fold purification of the enzyme was achieved by (NH4)2SO4 fractionation, chromatography on DEAE-cellulose, hydroxyapatite and Sephadex G-100 and affinity chromatography on 5'-AMP-Sepharose. The apparent molecular weight of the reductase was found to be about 38 000 on the basis of the elution volume from a Sephadex G-100 column. Maximum rate of reaction was observed between pH 6.0 and 6.2 in 0.1-0.2 M citrate buffer at 30 degrees C. The enzyme was markedly inhibited by thiol reagents. The reductase showed a high degree of specificity for cinnamoyl-CoA esters. Feruloyl-CoA was the substrate with the lowest Km value (73 muM) and highest V (230 nkat/mg) followed by 5-hydroxy-feruloyl-CoA, sinapoyl-CoA, p-coumaroyl-CoA, caffeoyl-CoA and cinnamoyl-CoA. No reaction took place with acetyl-CoA. The Km value for NADPH varied with the type of substrate. Km values of 28, 120, and 290 muM were found with feruloyl-CoA, sinapoyl-CoA, and p-coumaroyl-CoA, respectively. The rate of reaction observed with NADH was only about 5% of that found with NADPH. The reaction products CoASH and NADP+ inhibited the reaction. The Ki values were in the range of 0.5-1 mM and the inhibition was of a noncompetitive (mixed) type. The role of the reductase in the biosynthesis of lignin precursors is discussed.
 ...
PMID:Enzymic synthesis of lignin precursors. Purification and properties of a cinnamoyl-CoA: NADPH reductase from cell suspension cultures of soybean (Glycinemax). 0 54

1. At 21 degrees C incubation of NADH-ubiquinone-1 reductase (Complex 1) with trypsin caused selective inhibition of nicotinamide nucleotide transhydrogenase activity. The reduction of K3Fe(CN)6 by NADH or NADPH was unaffected, but a slow decrease in the rate of reduction of ubiquinone-1 by NADH was observed. 2. The pH-dependence of nicotinamide nucleotide transhydrogenase activity differed in Complex I and trypsin-treated Complex I. The trypsin-labile activity had a pH optimum of approx. 6.5, whereas the trypsin-resistant activity had a pH optimum of approx. 5.5 or less. 3. The trypsinlabile transhydrogenase activity was specifically inhibited by butanedione or phenylglyoxal and was identified with the enzyme catalysing energy-linked transhydrogenase activity in submitochondrial particles. 4. Polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate revealed that trypsin caused degradation of a polypeptide of mol.wt 20500 in parallel with the loss of transhydrogenase activity. 5. At 30 degrees C and higher trypsin concentrations, the rate of reduction of K3Fe(CN)6 by NADH or NADPH slowly decreased. Increased lability of NADH-K3Fe(CN)6 reductase activity to trypsin was observed when the endogenous phospholipid of Complex I was depleted by detergent or phospholipase A treatment. 6. Polyacrylamide-gel electrophoresis indicated that removal of phospholipid allowed much more extensive degradation of constituent polypeptides by trypsin. The subunits of the low-molecular-weight (type II) dehydrogenase (53000 and 26000 mol.wt.) were, however, relatively resistant to trypsin even in phospholipid-depleted preparations.
 ...
PMID:The effects of proteolytic digestion by trypsin on the structure and catalytic properties of reduced nicotinamide-adenine dinucleotide dehydrogenase from bovine heart mitochondria. 0 40


1 2 3 4 5 6 7 8 9 10 Next >>