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)

Glycerol-3-phosphate dehydrogenase (sn-glycerol-3-phosphate:NAD+ 2-oxido-reductase, EC 1.1.1.8) has been shown to be sensitive to inhibition by iodoacetate. The reaction of the enzyme with iodoacetate, which appears to be a simple bimolecular process, is accompanied by a corresponding loss of enzyme activity. In addition to changes in activity, the alkylation reaction was monitored by the incorporation of radioactivity from iodo[2-14C]acetate, by changes in amino acid composition, and by changes in the content of free sulfhydryl groups. It is concluded that there are two cysteine residues in the native dimeric enzyme which are essential for enzymic activity. The rate of inactivation was relatively insensitive to the presence of various compounds with the exception of NADH which markedly inhibited the reaction. Kinetic and binding studies showed that the binding of NADH prevents alkylation and, conversely, alkylation prevents NADH binding. From the pH dependence of the alkylation reaction, the pKa of the essential sulfhydryl groups was calculated to be 8.5 and it is suggested that the binding of coenzyme is independent of the state of ionization of these groups.
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PMID:The role of cysteine residues in the catalytic activity of glycerol-3-phosphate dehydrogenase. 3 50

Muscle samples were obtained from the gastrocnemius of 17 female and 23 male track athletes, 10 untrained women, and 11 untrained men. Portions of the specimen were analyzed for total phosphorylase, lactic dehydrogenase (LDH), and succinate dehydrogenase (SDH) activities. Sections of the muscle were stained for myosin adenosine triphosphatase, NADH2 tetrazolium reductase, and alpha-glycerophosphate dehydrogenase. Maximal oxygen uptake (VO2max) was measured on a treadmill for 23 of the volunteers (6 female athletes, 11 male athletes, 10 untrained women, and 6 untrained men). These measurements confirm earlier reports which suggest that the athlete's preference for strength, speed, and/or endurance events is in part a matter of genetic endowment. Aside from differences in fiber composition and enzymes among middle-distance runners, the only distinction between the sexes was the larger fiber areas of the male athletes. SDH activity was found to correlate 0.79 with VO2max, while muscle LDH appeared to be a function of muscle fiber composition. While sprint- and endurance-trained athletes are characterized by distinct fiber compositions and enzyme activities, participants in strength events (e.g., shot-put) have relatively low muscle enzyme activities and a variety of fiber compositions.
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PMID:Skeletal muscle enzymes and fiber composition in male and female track athletes. 12 49

1. The metabolic role of hepatic NAD-linked glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) was investigated vis-a-vis glyceride synthesis, glyceride degradation and the maintainence of the NAD redox state. 2. Five-week-old chickens were placed on five dietary regimes: a control group, a group on an increased-carbohydrate-lowered-fat diet, a group on a high-fat-lowered-carbohydrate diet, a starved group and a starved-refed group. In each group the specific activity (mumol/min per g wet wt. of tissue) of hepatic glycerol 3-phosphate dehydrogenase was compared with the activities of the beta-oxoacyl-(acyl-carrier protein) reductase component of fatty acid synthetase, glycerol kinase (EC 2.7.1.30) and lactate dehydrogenase (EC 1.1.1.27). 3. During starvation, the activities of glycerol 3-phosphate dehydrogenase, glycerol kinase and lactate dehydrogenase rose significantly. After re-feeding these activities returned to near normal. All three activities rose slightly on the high-fat diet. Lactate dehydrogenase activity rose slightly, whereas those of the other two enzymes fell slightly on the increased-carbohydrate-lowered-fat diet. 4. The activity of the beta-oxoacyl-(acyl-carrier protein) reductase component of fatty acid synthetase, a lipid-synthesizing enzyme, contrasted strikingly with the other three enzyme activities. Its activity was slightly elevated on the increased-carbohydrate diet and significantly diminished on the high-fat diet and during starvation. 5. The changes in activity of the chicken liver isoenzyme of glycerol 3-phosphate dehydrogenase in response to dietary stresses suggest that the enzyme has an important metabolic role other than or in addition to glyceride biosynthesis.
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PMID:Role of glycerol 3-phosphate dehydrogenase in glyceride metabolism. Effect of diet on enzyme activities in chicken liver. 16 14

The activities of glycerol 3-phosphate dehydrogenase (EC 1.1.1.8), glycerol kinase (EC 2.7.1.30), lactate dehydrogenase (EC 1.1.1.27), "malic' enzyme (L-malate-NADP+ oxidoreductase; EC 1.1.1.40) and the beta-oxoacyl-(acyl-carrier protein) reductase component of the fatty acid synthetase complex were measured in nine hepatoma lines (8 in rats, 1 in mouse) and in the livers of host animals. With the single exception of Morris hepatoma 16, which had unusually high glycerol 3-phosphate dehydrogenase activity, the activities of glycerol 3-phosphate dehydrogenase and glycerol kinase were highly correlated in normal livers and hepatomas (r = 0.97; P less than 0.01). The activities of these two enzymes were not strongly correlated with the activities of any of the other three enzymes. The primary function of hepatic glycerol 3-phosphate dehydrogenase appears to be in gluconeogenesis from glycerol.
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PMID:Proportional activities of glycerol kinase and glycerol 3-phosphate dehydrogenase in rat hepatomas. 17 86

This paper reviews most of the clinical studies on the mode of action of halofenate, an established hypolipidemichypouricemic agent in man. In yeast cutlures and in isolated rat adipocytes, halofenate was found to inhibit the conversion of pyruvate to acetyl CoA. While pyruvate dehydrogenase was inhibited in vitro, halofenate also inhibited the activety of various other isolated enzymes. In rats maintained on halofenate in the diet (0.02-0.10%) for 2-14 days, there were 20-40% decreases in plasma cholesterol, trigly cerides, phospholipids, and free fatty acids. Inhibition of liver HMG-CoTA reductase does not appear to account for the hypocholesterolemic effect, and activation of mitochondrial alpha-glycerophosphate dehydrogenase does not explain the hypotriglyceridemic action. Kinetic measurements of the serum appearance and disappearance of triglycerides in drug-treated rats suggest that the hypotriglyceridemic activity is due to a net inhibition of hepatic triglyceride synthesis. Reduction of very low density lipoprotein (VLDL) and high density lipoprotein (HDL) levels in rats with sucrose-induced hyperlipidemia and normalization of the altered apolipoprotein profiles are in accord with the effects of halofenate on plasma triglyceride and cholesterol levels. The reduced insulin-to-glucagon ratio observed in Zucker obese hyperlipemic rats is also consistent with halofenat's hypotriglyceridemic activity. Preliminary experiments in rats on the mechanism of its hypoglycemic activity, observed in some diabetic hyperlipidemic patients, indicate that halofenate acts differently than conventional oral hypoglycemic agents. Some, but not all, of the effects of halofenate were observed with clofibrate at two to ten times higher levels.
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PMID:Studies on the mechanism of action of halofenate. 31 18

Mycotoxic porcine nephropathy was induced by p.o. administration of crystalline ochratoxin A for periods of 5 days, 3 months and 2 years. Enzyme activities of the renal tissue were studied histochemically. These were NADH-tetrazolium reductase, NADPH-tetrazolium reductase, lactate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, alpha-glycerophosphate dehydrogenase, unspecific acid phosphatase and unspecific alkaline phosphatase. The activity of NADH-tetrazolium reductase and succinate dehydrogenase was reduced in the proximal tubule of all nephrons after 5 days ochratoxin A exposure and remained reduced after 3 months and 2 years exposure. The effect of ochratoxin A on these enzymes would appear to cause the impairment of proximal tubular function and the morphological changes observed in the proximal tubule in ochratoxin A-induced mycotoxic porcine nephropathy. The localization of alterations in enzyme activity corresponds to the localization of ochratoxin A previously demonstrated in the kidney. The activities of NADPH-tetrazolium reductase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and unspecific alkaline phosphatase were reduced focally corresponding to the areas with focal tubular atrophy and the degree of reduction was roughly parallel to the degree of atrophy.
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PMID:Ochratoxin A-induced mycotoxic porcine nephropathy: alterations in enzyme activity in tubular cells. 47 26

In the paper we observed histochemically the distribution and activity of 16 enzymes in the normal rat gastric mucosa. The lysosomal enzymes were demonstrated by the method of semipermeable membranes (LOJDA 1972). At the proof of dehydrogenases aqueous and gel media were used. The parietal cells of the gastric mucosa contained a moderate activity of acid phosphatase, E-600 resistant esterase, and only a very slight activity of beta-glucuronidase and N-acetyl-beta-D-glucosaminidase. The macrophages of the interstice contained a high activity of beta-glucruonidase, acid phosphatase, E-600 resistant esterase and a low activity of N-acetyl-beta-D-glucosaminidase. The chief cells of the rat gastric mucosa, in contrast to the human, did not contain nonspecific esterase and also in them acid phosphatase was mostly lacking. The alkaline phosphatase was found only in the endothelium of the capillaries of the gastric mucosa. The parietal cells contained high activities of succinate dehydrogenase, alpha-glycerophosphate dehydrogenase, beta-hydroxybutyrate dehydrogenase, NADH tetrazolium reductase, a lower activity of NADPH tetrazolium reductase, as well as other soluable dehydrogenases. At the examination of dehydrogenases using aqueous as well as gel media with PMS during optimal short incubation periods, we found more and less active forms of parietal cells. The different oxidoreductase capacity of parietal cells in normal rat gastric mucosa can point to their unequal-functional load at the production of hydrochloric acid. The findings obtained are compared with the findings in older papers concerning different experimental animals and with the distribution of enzymes in the human gastric mucosa.
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PMID:Histochemical localization of enzymes in the normal rat gastric mucosa using the technique of the semipermeable membranes and the other methods. 82 7

1. Simvastatin, a competitive inhibitor of 3-hydroxy-3-methyl glutaryl CoA reductase, lowers the plasma cholesterol level and has been approved for treatment of hyperlipoproteinaemia. 2. Simvastatin has been studied for its effects on hepatic microsomal drug metabolism in rat. No induction of 7-ethoxyresorufin-O-deethylase (EROD), ethoxycoumarin-O-deethylase (ECOD) and of UDP-glucuronosyltransferases were found, in vitro, after administration of 0.5, 1.5 and 10 mg/kg per day for 22 days. 3. Epoxide hydrolases (microsomal and cytosolic) were also unchanged after treatment with simvastatin. 4. No increase of the palmitoyl CoA oxidase activity or of mitochondrial glycerol phosphate dehydrogenase activity occurred. 5. Fatty acid distribution in rat liver microsomal phosphatidylcholines showed a significant decrease of C16:1 and a significant increase of C20:4 acids.
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PMID:Effects of simvastatin, a lipoprotein-lowering drug, on the hepatic enzymes involved in drug metabolism in the Wistar rat. 177 61

Postural muscles have many type I myofibers, which reacted strongly for acid-stable myosin ATPase and were unreactive for alkali-stable myosin ATPase (Ariano et al., J. Histochem. Cytochem., 21:51-55, 1973; Armstrong et al., Am. J. Anat., 163:87-98, 1982; Smith et al., J. Neurophysiol., 40:503-513, 1977). House shrews (Suncus murinus) keep abducting their limbs in locomotion and hardly lift their trunk off the ground. The limb muscles of Suncus were examined by histochemical methods to determine whether the locomotory and postural behavior is related to the proportion of type I myofibers. The observation of whole cross sections from the triceps surae, flexor digitorum superficialis, quadriceps femoris, and caudally situated muscles in the thigh showed that all myofibers of these muscles were unreactive for acid-stable myosin ATPase and strongly reactive for alkali-stable myosin ATPase: Those were classified as type II myofibers. Type II myofibers showed a weak (type IIB), moderate (type IIAB), or strong (type IIA) reaction for NADH tetrazolium reductase. Part of type IIA myofibers reacted weakly to moderately for menadione-linked glycerol-3-phosphate dehydrogenase (m-GPD), which predominated in the soleus muscle. Type IIAB, type IIB, and the remainder of type IIA myofibers reacted strongly for m-GPD. The limb muscles contained subtypes of type II myofibers but no type I myofibers. In Suncus murinus, type I myofibers specialized for a postural maintenance may not be required because all myofibers function exclusively for propulsion.
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PMID:Composition of myofiber types in limb muscles of the house shrew (Suncus murinus): lack of type I myofibers. 214 5

The effects of hypothyroidism and of replacement therapy with T4 or T3 were studied on the enzymatic activities of liver subcellular fractions isolated from Cynomolgus monkeys. Animals were sacrificed 20 days after thyroidectomy. In mitochondria, thyroidectomy decreased significantly the respiratory chain activity (succinate cytochrome c-reductase), the transfer of cytosolic reducing equivalents (glycerol-3-phosphate dehydrogenase) and the phosphorylating capacity (oligomycin-sensitive ATPase and state 3 respiratory rate). The activity of nucleolar and nucleoplasmic RNA polymerases dropped by about 50% in hypothyroid monkeys. In T4 (2.5 micrograms/kg/d) or T3 (1 microgram/kg/d) treated thyroidectomized animals, the iodothyronine concentrations and the activity of mitochondria and nuclei enzymes were halfway between normal and hypothyroid values. Thus, the mitochondrial effects of thyroidectomy in monkey are, as in rat, at least partly secondary to a decrease in nucleocytoplasmic protein synthesis.
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PMID:[Effect of hypothyroidism on mitochondrial energy metabolism and nuclear synthesis of RNA in the liver of Cynomolgus monkeys]. 242 8


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