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Query: EC:1.1.1.49 (glucose-6-phosphate dehydrogenase)
 7,794 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Coho salmon (Oncorhynchus kisutch), 8 to 18 months of age, were maintained in culture tanks and were fed three semipurified diets. The diets contained 40% of energy from protein and 11.5%, 23%, or 46% of energy from lipid. The body weight gain and food conversion factors were similar among groups of fish fed the diets in each of the three experiments. Wet weight of mesenteric adipose tissue increased with increased amount of lipid in the diet; however, epaxial muscle lipid content was not influenced by the lipid content of the diet. Several hepatic and adipose tissue lipogenic enzymes (fatty acid synthetase, citrate cleavage enzyme, malic enzyme, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and NADP-isocitrate dehydrogenase) were assayed. These lipogenic enzymes exhibited high activities in liver and relatively low concentration in adipose tissue of the fish. The activities of all the hepatic lipogenic enzymes assayed, except for NADP-isocitrate dehydrogenase, were depressed as the level of lipid in the diet was increased; however, the activities of these enzymes in mesenteric adipose tissue were not influenced by the diets fed. The results of this study indicate that dietary lipid depresses hepatic lipogenic enzyme activities and that the liver may be a more important site for fatty acid synthesis than is adipose tissue in coho salmon.
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PMID:Influence of dietary lipid on lipogenic enzyme activities in coho salmon, Oncorhynchus kisutch (Walbaum). 1 2

Aggregation of thrombocytes, caused by ADP, affected the rate of anaerobic breakdown of carbohydrates due to inhibition of the glucose degradation, while the rate of lactate formation was not distinctly altered. Content of NAD was decreased simultaneously with an increase in content of NADP; the activity of glucose-6-phosphate dehydrogenase was distinctly increased but the unaltered activity of 6-phosphogluconate dehydrogenase was observed; content of reduced glutathione was increased 15-fold. The activity of NADP-dependent glutathione reductase was increased under effect of ADP; at the same time, the activity of NAD-dependent glutathione reductase did not depend on the diphosphate effect.
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PMID:[Relationship between glycolysis and pentose cycle intensity and thrombocyte aggregation induced by ADP in man]. 2 84

Sperm from normal human donors and a G6PD-A- individual were examined for x-linked glucose-6-phosphate dehydrogenase activity and autosomally linked 6-phosphogluconate dehydrogenase activity. With the use of fluorescence microscopy, we divised a procedure to visualise in individual sperm cells the fluorescence of reduced coenzyme NADPH formed by each of the two enzymes in the presence of appropriate substrates. We found significant differences in the population distribution of sperm expressing each of the two activities, and the ratio of the two activities in sperm homogenate is very different from the one found in erythrocyte lysates. The possibility of haploid gene expression has been considered in interpreting these results.
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PMID:Glucose-6-phosphate dehydrogenase (G6PD) activity of human sperm. 2 66

The contents of adenine nucleotides as well as steady-state concentrations of a number of glycolytic, pentose phosphate-pathway and tricarboxylic acid-cycle intermediates were measured in extracts of livers from normal and phenobarbital-treated rats that were perfused with p-nitroanisole. Metabolites were measured in livers that were freeze-clamped during periods of maximal rates of drug metabolism. Treatment of rats with phenobarbital increased rates of p-nitroanisole O-demethylation approx. fivefold. The concentrations of lactate, xylulose 5-phosphate and ribulose 5-phosphate were increased by phenobarbital treatment, whereas that of fructose 1,6-bisphosphate declined. Perfusion of livers with p-nitroanisole produced significant increases in 6-phosphogluconate and ribulose 5-phosphate in livers from phenobarbital-treated rats, but not in livers from control rats. Treatment of rats with phenobarbital caused [NADP(+)]/[NADPH] to change in the direction of more oxidation, as calculated from measured concentrations of 6-phosphogluconate and ribulose 5-phosphate; however, the [NADP(+)]/[NADPH] ratio calculated from ;malic' enzyme was not changed. Additions of p-nitroanisole produced a reduction of NADP(+) as calculated from 6-phosphogluconate dehydrogenase activity, but did not alter the [NADP(+)]/[NADPH] ratio calculated from substrates assumed to be in equilibrium with ;malic' enzyme. Activities of both glucose 6-phosphate dehydrogenase and ;malic' enzyme were increased by phenobarbital treatment. NAD(+) became more reduced as a result of phenobarbital treatment; however, perfusion of livers with p-nitroanisole did not cause a change in the oxidation-reduction state of this nucleotide. Concentrations of adenine nucleotides in livers were not altered significantly by treatment of rats with phenobarbital; however, a significant decline in the [ATP]/[ADP] ratio occurred during mixed-function oxidation of p-nitroanisole in livers from phenobarbital-treated rats, but not in livers from normal rats. Perfusion of livers with two other substrates for mixed-function oxidation, hexobarbital and aminopyrine, produced an increase in the [NADP(+)]/[NADPH] ratio calculated from ;malic' enzyme. In contrast with livers perfused with p-nitroanisole, there was no significant change in adenine nucleotides in livers exposed to hexobarbital or aminopyrine. Addition of 2,4-dinitrophenol (25mum) to the perfusate containing aminopyrine decreased the [ATP]/[ADP] ratio and tended to prevent the oxidation of NADPH observed with aminopyrine alone. Thus in the presence of an uncoupler of oxidative phosphorylation, NADPH generation may exceed its utilization via mixed-function oxidation.
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PMID:Alterations in nicotinamide and adenine nucleotide systems during mixed-function oxidation of p-nitroanisole in perfused livers from normal and phenobarbital-treated rats. 2 4

Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glutathione reductase and pyruvate kinase of Candida utilis and baker's yeast, when in anionic form, were adsorbed on a cation exchanger, P-cellulose, due to affinities similar to those for the phosphoric groups of their respective substrates; thus, glucose-6-phosphate dehydrogenase was readily eluted by either NADP+ or NADPH, glutathione reductase by NADPH, 6-phosphogluconate dehydrogenase by 6-phosphogluconate, and pyruvate kinase by either ATP or ADP. This type of chromatography may be called "affinity-adsorption-elution chromatography"; the main principle is different from that of so-called affinity-elution chromatography. Based on these findings, a large-scale procedure suitable for successive purification of several enzymes having affinities for the phosphoric groups of their substrates was devised. As an example, glucose-6-phosphate dehydrogenase was highly purified from baker's yeast and crystallized.
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PMID:Successive purification of several enzymes having affinities for phosphoric groups of substrates by affinity chromatography on P-cellulose. 2 26

1. The mechanisms that control the oxidative phase of the pentose phosphate cycle in mussel hepatopancreas were investigated. 2. The effects of GSSG (oxidized glutathione) on the inhibition of glucose 6-phosphate dehydrogenase by NADPH [Eggleston & Krebs (1974) Biochem. J. 138, 425-435] extend to 6-phosphogluconate dehydrogenase. 3. The effect of GSSG on both enzymes increases as the [NADP+1]/[NADPH] ratio decreases; greater percentage deinhibition always was obtained for 6-phosphogluconate dehydrogenase. 4. Increasing concentration of GSSG increased the percentage deinhibition. This effect is more pronounced with 6-phosphogluconate dehydrogenase. 5. We confirmed the apparent imbalance between the activities of the two enzymes [sapag-Hagar, Lagunas & Sols (1973) Biochem. Biophys. Res. Commun, 50, 179-185] in the presence of 10mM-Mg2+. 6. The imbalance practically disappears when the substrate concentrations are less than saturating and Mg2+ approaches physiological concentrations. 7. The addition of GSSG at physiological concentrations allows the activities of both enzymes to be measured at high [NADPH]/[NADP+] ratios ratios and the co-operative action of GSSG and Mg2+ on the imbalance between the two enzymes to be verified. 8. The control of the activity of the two enzymes of the pentose cycle could be carried out by deinhibition of the two dehydrogenases and by the intracellular concentrations of substrates and inorganic ions.
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PMID:Regulation of the oxidative phase of the pentose phosphate cycle in mussels. 2 52

At present soluble NADP-dependent dehydrogenases are histochemically demonstrated in three different ways: according to the standard method incubation in aqueous media leads to the precipitation of formazan, the formation of which depends entirely on the presence of endogeneous NADPH2-tetrazolium reductases. With the two more recently established methods these reductases are by-passed with the use of intermediate electron acceptors incorporated in the medium. In addition, enzyme diffusion is inhibited either by an increased viscosity of the medium (PVA) or by a semipermeable membrane separating the medium from the section. Depending on the technique applied different distribution patterns have been described. By altering the concentrations of substrates, coenzyme, tetrazolium salt and cytochrome oxidase inhibitor, it was possible to improve both the PVA and membrane methods. Although similar results were obtained, because of its advantages the PVA method is recommended in this report and a detailed description is given. Using the latter for the demonstration of glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH), malic enzyme (ME) and isocitrate dehydrogenase (ICDH), characteristic distribution patterns were obtained in the liver parenchyma of male and female rats. For the first time a high G6PDH activity could be demonstrated in nonparenchymal cells which are mainly found in zone 1 of the liver acinus.
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PMID:NADP-dependent dehydrogenases in rat liver parenchyma. I. Methodological studies on the qualitative histochemistry of G6PDH, 6PGDH, malic enzyme and ICDH. 2 20

Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP oxidoreductase, EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (6-phospho-D-gluconate: NADP oxidoreductase, EC 1.1.1.44) were purified approx. 1700 fold and 330 fold, respectively, from Candida boidinii grown on methanol. The final enzyme preparations were homogeneous as judged by polyacrylamide gel electrophoresis. The molecular weights of the enzymes were estimated to be 118 000 and 110 000, respectively. Both enzymes are composed of two probably identical subunits and the molecular weights of the polypeptide chains were calculated to be 61 000 and 58 000, respectively. From a consideration of enzyme activities and types of inhibition by different metabolites the role of these two enzymes in glucose- and methanol-metabolism is discussed.
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PMID:Purification and properties of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase from a methanol-utilizing yeast, Candida boidinii. 3 36

The rate of in vivo fatty acid synthesis as well as the levels of glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), malic enzyme (ME), citrate cleavage enzyme (CCE), acetyl-CoA carboxylase (ACX) and fatty acid synthetase (FAS) activities, have been studied in the liver of rats fed a fat-free diet for 7 days, followed by diets containing different amounts of soybean oil (0 to 24.79 kcal%) for 7 days. The dietary fat depressed activities of G6PD, 6PGD, ME, CCE, and FAS significantly at 1.24 or 2.48 kcal%. On the other hand, AC activity and the rate of fatty acid synthesis were decreased when the level of dietary fat was 12.39 kcal% or greater. These findings, as well as the pattern of decrement of enzyme activities and of lipogenesis, suggest a close correlation of fat feeding to ACX activity and fatty acid synthesis. The results also suggest that changes of G6PD, 6PGD, ME, CCE, and FAS activities may be largely independent of those modifications which occur in the substrate flux, concomitantly with the decrease of lipogenesis caused by the inclusion of fat in the diet.
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PMID:Response of rat hepatic fatty acid synthesis and activities of related enzymes to changes in level of dietary fat. 3 77

Impaired testosterone biosynthesis in Leydig cells from streptozotocin treated rats is correlated with the reduced activity of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and isocitrate dehydrogenase. The results shown demonstrate that in the diabetic state the activity of these enzymes is reduced by almost 50 to 59% from normal levels. Insulin treatment restored their activities to normal levels. The diminished supply of NADPH in diabetic interstitial tissue is not the unique factor in the control of steroidogenesis, since the availability of large amounts of exogenous NADPH in the incubations of Leydig cell did not reduce the differences in testosterone synthesis observed when compared with normal cells.
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PMID:NADPH generating enzymes in Leydig cells from diabetic rats. 3 55


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