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)

Long-chain alcohols are synthesized in the mouse preputial gland tumor (ESR-586) by NADPH:acyl-CoA oxidoreductase. In this study, a series of labeled acids was tested as substrates for the oxidoreductase in a cell-free system from the tumor, and the distribution of label into alcohols, waxes, and other products was determined. The system contained the labeled acid, an acyl-CoA-generating system, an NADPH-generating system, and tumor homogenate. The highest rates of alcohol synthesis were obtained with palmitic (16:0), heptadecanoic (17:0), stearic (18:0), myristic (14:0), elaidic (18:1 trans), and linoleic (18:2) acids, which yielded, respectively, 151, 124, 102, 76, 65, and 35 pmol alcohol/min per mg protein. Decanoic (10:0), lauric (12:0), oleic (18:1 cis), linolenic (18:3), arachidonic (20:4), and behenic (22:0) acids all gave lower activities. Acyl-CoA formation did not appear to be rate limiting with any of the substrates tested except behenic acid. In addition to the fatty alcohol product, a small amount of fatty aldehyde was formed in the system. Incorporation of the labeled fatty acids into wax esters was examined and the distribution of label between the alcohol and acid components of the waxes was determined. Incubation of [1-(14)C]palmitic acid yielded 3.4% free alcohol, 8.3% alcohol esterified in waxes, and 7.7% palmitoyl groups esterified into waxes, whereas, at the other extreme, [1-(14)C]linolenic acid yielded 0.8%, 0.6%, and 38%, respectively, into the homologous components.-Wykle, R. L., B. Malone, and F. Snyder. Acyl-CoA reductase specificity and synthesis of wax esters in mouse preputial gland tumors.
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PMID:Acyl-CoA reductase specificity and synthesis of wax esters in mouse preputial gland tumors. 3 66

Certain physiological differences between individuals in different populations of the mussel, Mytilus edulis, are described. In particular, the scope for growth differs in space and time and may be used to assess the animals' physiological condition. When the required measurements are made in the field, the rates of growth predicted from the physiological data agree well with observed rates of growth. An alternative approach utilizes mussels transplanted to various waters, with indices of condition then measured in then measured in the laboratory under standard conditions; an example of this approach is illustrated. Laboratory experiments are used to equate various levels of physiological condition with fecundity, in an attempt to equate physiological effects on the individual with likely population damage. A cytochemical index of stress is described, based on the latency of lysosomal enzymes; spatial variability in this index, and its relation with the scope for growth, are discussed. Finally, the results of some experiments on the effects of petroleum hydrocarbons on mussels are described and the presence of inducible activity of NADPH-dependent tetrazolium reductase in the blood cells is demonstrated. Certain considerations that apply in adopting similar measurements of biological effects of pollution in environmental monitoring programmes are discussed.
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PMID:Measurement of the responses of individuals to environmental stress and pollution: studies with bivalve molluscs. 4 Feb 78

Biliverdin reductase was purified from pig spleen soluble fraction to a purity of more than 90% as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was a monomer protein with a molecular weight of about 34,000. Its isoelectric point was at 6.1-6.2. The enzyme was strictly specific to biliverdin and no other oxiodoreductase activities could be detected in the purified enzyme preparation. The purified enzyme could utilize both NADPH and NADH as electron donors for the reduction of biliverdin. However, there were considerable differences in the kinetic properties of the NADPH-dependent and the NADH-dependent biliverdin reductase activities: Km for NADPH was below 5 microM while that for NADH was 1.5-2 mM; the pH optimum of the reaction with NADPH was 8.5 whereas that of the reaction with NADH was 6.9; Km for biliverdin in the NADPH system was 0.3 microM whereas that in the NADH system was 1-2 microM. In addition, both the NADPH-dependent and NADH-dependent activities were inhibited by excess biliverdin, but this inhibition was far more pronounced in the NADPH system than in the NADH system. IX alpha-biliverdin was the most effective substrate among the four biliverdin isomers, and the dimethylester of IX alpha-biliverdin could not serve as a substrate. Biliverdin reductase was also purified about 300-fold from rat liver soluble fraction. The hepatic enzyme was also a monomer protein with a molecular weight of 34,000 and showed properties quite similar to those of the splenic enzyme as regards the biliverdin reductase reaction. The isoelectric point of the hepatic enzyme, however, was about 5.4. It was assumed that NADPH rather than NADH is the physiological electron donor in the intracellular reduction of IX alpha-biliverdin. The stimulatory effects of bovine and human serum albumins on the biliverdin reductase reactions were also examined.
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PMID:Purification and properties of biliverdin reductases from pig spleen and rat liver. 4 Sep 68

Two NADPH-dependent aromatic aldehyde-ketone reductases purified from guinea pig liver catalyzed oxidoreduction of 17 beta-hydroxysteroids and 17-ketosteroids. One enzyme efficiently oxidized 5 beta-androstanes and reduced 17-ketosteroids of A/B cis configuration, whereas the other enzyme efficiently oxidized 5 alpha-androstanes and equally reduced both 5 alpha-and 5 beta-androstanes of 17-ketosteroids. However, aromatic aldehydes and ketones, and 3-ketosteroids were irreversibly reduced by the two enzymes. The two enzymes utilized NADP+ or NADPH as cofactor, but little activity with NAD+ or NADH was found. Phosphate ions enhanced the NAD+-dependent dehydrogenase activity and NADH-dependent reductase activity of the two enzymes, whereas the activities with NADP+ and NADPH were not affected. The ratios of the two activities of ketone reduction and 17 beta-hydroxysteroid oxidation of the two enzymes were almost constant during the purification steps after the two enzymes had been separated by DEAE-cellulose chromatography. By kinetic studies and electrophoresis and isoelectric focusing experiments it was confirmed that both of the two enzymes were responsile for the reduction aldehydes, ketones, and ketosteroids and for the oxidation of 17 beta-hydroxysteroids. These results indicate that 17 beta-hydroxysteroid dehydrogenases may play important roles in the metabolism of exogeneous aldehydes and ketones as well as steroids.
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PMID:Guinea pig liver aromatic aldehyde-ketone reductases identical with 17 beta-hydroxysteroid dehydrogenase isozymes. 4 Sep 69

The in vitro metabolism of the antitumor anthracycline antibiotic, aclacinomycin-A, was studied using rat liver homogenate. In the presence of NADH or NADPH, aclacinomycin-A was converted to aclacinomycin-A analogs, MA144 M1 and MA144 N1, which were stereospecifically reduced at the keto group of the C-4''' position of L-cinerulose in aclacinomycin-A. Subcellular fractionation indicated that the production of MA144 M1, which was reduced to L-amicetose, was catalyzed by NADPH-dependent soluble cinerulose reductase I, and the production of MA144 N1, which was reduced to L-rhodinose, was catalyzed by NADPH-dependent soluble cinerulose reductase II and NADH-dependent microsomal cinerulose reductase. The properties of these three enzymes were studied. Soluble cinerulose reductase I which produces MA144 M1 showed a optimum pH at 6.3, Km values of 3.3 x 10(-4) M for aclacinomycin-A and 3.2 x 10(-5) M for NADPH. Soluble cinerulose reductase II which produces MA144 N1 showed a pH optimum at 6.3 and Km values of 2.0 x 10(-3) M for aclacinomycin-A and 4.0 x 10(-5) M for NADPH. All thesse reductases were sensitive to sulfhydryl reagents and were inhibited by vitamin K3. Microsomal cinerulose reductase showed sensitivity to diconmarol and ferrous ion. The main nondegradative pathways of aclacinomycin-A were discussed from these results.
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PMID:Reduction of cinerulose in aclacinomycin-A by soluble and microsomal cinerulose reductases. 4 94

The in vitro degradation of the new antitumor anthracycline antibiotic, aclacinomycin-A, was studied using rat liver homogenate. In the presence of NADH or NADPH, the glycosidic bond at C-7 position of aclacinomycin-A was reductively cleaved to produce 7-deoxyaklavinone and 7-deoxyaklavinone dimer, MA144 E1. Subcellular fractionation indicated that most of the enzyme activity was present in the microsomal fraction and required anaerobic condition and NADPH. The purified enzyme reduced the glycosidic metabolites, MA144 M1 and MA144 N1, as well as aclacinomycin-A. The optimum pH for the anthracycline glycoside reductase reaction using aclacinomycin-A as substrate was 7.4. The enzyme was sigmoidally saturated with aclacinomycin-A and showed the concentration of 1.2 x 10(-4) M required for half maximal activity, and Km value of 7.7 x 10(-5) M for NADPH. The degradative pathway of aclacinomycin-A and its glycosidic metabolites was discussed.
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PMID:Reduction of anthracycline glycoside by NADPH--cytochrome P-450 reductase. 4 95

Intraperitoneal administration of diazepame and phenazepame into rats /at a dose 50 mg/kg/ within 4 days did not induce liver microsomal enzymes. After administration of chlordiazepoxide at the same dose content of cytochrome P-450 was increased and the rate of dimethylaniline demethylation was elevated. Content of protein as well as NADPH-cytochrome-c-reductase and glucose-6-phosphatase activities were increased after intraperitoneal administration of all the preparations at a dose 100 mg/kg within 4 days. Experiments on the potentiation of hexenal effect demonstrated the decrease in the time of sleep in animals, treated with chlordiazepoxide at a dose 100 mg/kg of body weight.
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PMID:[Effect of 1,4-benzodiazepine tranquilizers on the activity of the hepatocyte hydroxylating complex and glucose-6-phosphatase in white rats]. 4 17

The aerobic NADPH reduction of cytochrome P-450LM has been investigated on microsomes, as well as on the solubilized enzyme system in the associated, disintegrated, and reconstituted state, respectively. P-450 exhibits biphasic reduction kinetics of about 70/30% phase distribution and rate constants differing 10-fold. The partial reactions are due to organizational asymmetries, the cytochrome being either incorporated into P-450/reductase associates (cluster) or localized outside (randomly distributed, homoassociated, weakly cluster-associated). Triton N-101 disintegrates the different associate structures, consequently followed by the disappearance of the rapid reaction phase. The enzyme system can be reconstituted; at microsomal stoichiometry the respective standard parameters are approached, depending on the composition and structural organization of the phospholipid. The reorganization without any membrane matrix is obviously thermodynamically determined.
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PMID:Kinetics of elementary steps in the cytochrome P-450 reaction sequence. III. NADPH reduction of cytochrome P-450LM at different integrational levels. 4 45

The aerobic NADPH reduction of the Triton N-101 disintegrated cytochrome P-450LM system has been studied. At this organization level--the components being dispersed in solution--a first-order monophasic reaction is exhibited. Neither the complex formation of cytochrome and reductase, respectively, nor preceding diffusion is rate limiting. The initial rate follows the ratio reductase/P-450 (mole/mole) thus indicating a Michaelis-Menten type enzyme mechanism. A model treatment of the reaction fits the systems behaviour as a whole. A multiparameter equilibrium state and different specified time function equations were developed for the determination of individual step rate constants and other system parameters as well.
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PMID:Kinetics of elementary steps in the cytochrome P-450 reaction sequence. IV. Mechanism of the NADPH reduction reaction of cytochrome P-450LM. 4 46

The complex monooxygenatic enzyme exhibits different functional behaviour at different integrational levels, thus indicating distinct organizational states. The aerobic NADPH reduction of microsomes, solubilized and reconstituted systems follows a biphasic kinetics, the two phases are attributed to associated state (cluster) and random cytochrome P-450 reduction. States of different cytochrome P-450/reductase ratio (associates) could not be differentiated in rate. Detergents (Triton N-101, cholate) are capable of disintegrating the system, at last only monophasic slow reduction is observed. The hydroxylation activity follows the respective reduction behaviour. Sedimentation analysis proves the distinct structural states. Reconstitution of the system can be achieved by means of detergent dilution as well as by combining the constituents. The activity of the reconstituted system depends on the composition of the phospholipids as well as on its organizational state. The reassociation of the solubilized enzyme system at nearly microsomal components stoichiometry (Triton N-101 dilution) proves to be thermodynamically governed leading to self-organization of the system without matrix prerequisite. Individual step rate constants of the reduction reaction and other system parameters are accessible by means of a model treatment of the disintegrated system. Further application to mixed kinetics systems is in progress.
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PMID:NADPH reduction of cytochrome P-450 at different integrational levels of the enzyme system. 4 48


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