Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

To elucidate the causes of changes of carbohydrate metabolic pathways, the time course of utilization of dietary [U-14C]sucrose and induction of enzyme activities in the livers of rats were investigated. Adult male rats of BHE strain were refed after a fast of 2 days. The nutritionally complete refeeding diet contained 60% sucrose as the only source of carbohydrate. [U-14C]Sucrose was included in the diet on either day 1 or day 2, or both of refeeding. During the first day of refeeding, the radioactivity was incorporated mainly into liver glycogen which rose to over 100 mg/g. During the second day, little 14C appeared in the liver glycogen, which decreased sharply while glucose-6-phosphatase activity increased. The glycogenic pathway thus appeared to be blocked. On the other hand, 14C incorporation in the liver fat was minimal during the first day, but was quite extensive during the second day of refeeding. The enhanced lipogenesis was accompanied by large increases of activities of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADP-malic dehydrogenase. Results clearly indicate that the carbohydrate load in the liver of intact animals was initially metabolized by the glycogenic pathway. When glycogenesis stopped, carbohydrate was metabolized differently. The enhanced incorporation of [U-14C]sucrose into liver lipids indicates an increased formation of acetyl CoA and an accelerated formation and use of NADPH, probably from increasing dehydrogenase activities. Our data suggest that the blockage of synthesis of glycogen with the continuation of carbohydrate load was a primary cause in over-shooting induction of hepatic dehydrogenase activities and lipogenesis.
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PMID:Stoppage of glycogenesis and "over-shoot" of induction of lipogenesis and its related enzyme activities in the liver of fasted-refed rats. 17 17

The effects of two environmental temperatures (T; 16 degrees and 31 degrees), five diet dilutions (D; 0%, 12.5%, 25%, 37.5% and 50%), and five daily treadmill running periods (E; 10 minutes, 40 minutes, 70 minutes, 100 minutes, and 130 minutes) upon enzyme activities of liver and adipose tissue of male rats were observed. Liver enzymes studied were glucose-6-phosphatase (G6Pase), 6-P-gluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), fructose diphosphatase (FDPase), NADP-isocitrate dehydrogenase (ICDH), and malic enzyme (ME). Adipose tissue (epididymal fat) enzymes (6PGD, G6PD, and ME) were studied as well as the in vitro incorporation of the 14C of [U-14C] glucose into liberated 14CO2 and into the triglycerides, free fatty acids, and total lipids by adipose tissue slices. Equations describing regression surfaces for these responses (expressed as units/100 g body weight) could contain significant linear coefficients of the independent variables (T, D, and E), their first order interactions, and quadratic coefficients for D and E. Significnat regression coefficients for activities of liver enzymes associated with increased lipogenesis (6PGD, G6PD, and ME) produced response surfaces with conformations generally concave downward. All enzymes possessed positive and negative linear and quadratic coefficients for D which caused response surfaces to be concave downward with respect to that variable. Also, 6PGD and G6PD (positive linear and negative quadratic coefficients for E) exhibited response surfaces concave downward with respect to E. Additionally, 6PGD showed greater activity at 31 degrees than at 16 degrees while G6PD showed no effect of temperature on activity. Liver ICDH, probably important in supplying reducing equivalents for fatty acid synthesis, evidenced response surfaces almost identical to those for 6PGD. Significant regression coefficients for activity of liver enzymes associated with increased gluconeogenesis (FDPase and G6Pase) produced for FDPase a response surface concave downward with respect to both D and E with greater values at 31 degrees than at 16 degrees; but for G6Pase non-concave surfaces with lesser values at 31 degrees than at 16 degrees. Significant regression coefficients for activities of adipose enzymes associated with increased lipogenesis produced for 6PGD a response surface concave upward due to negative linear and positive quadratic coefficients for both D and E. For G6PD and ME regression surfaces were concave upward with respect to E, but these were modified by positive and negative linear coefficients, respectively, for D. Significant regression coefficients for incorporation of the 14C of glucose into triglycerides and free fatty acids of adipose tissue slices and their production of 14CO2 yielded response surfaces concave upward with respect to E (negative linear and positive quadratic coefficients). In addition, the surface for free fatty acids was concave upward with respect to D. The 14CO2 production was greater at 16 degrees than at 31 degrees...
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PMID:Effects in the rat of environmental temperature, diet dilution, and treadmill running on liver and adipose enzymes and metabolism of 14C-glucose: a multiple regression analysis. 18 37

Extracts of Pseudomonas C grown on methanol as a sole carbon and energy source contain a methanol dehydrogenase activity which can be coupled to phenazine methosulfate. This enzyme catalyzes two reactions namely the conversion of methanol to formaldehyde (phenazine methosulfate coupled) and the oxidation of formaldehyde to formate (2,6-dichloroindophenol-coupled). Activities of glutathione-dependent formaldehyde dehydrogenase (NAD+) and formate dehydrogenase (NAD+) were also detected in the extracts. The addition of D-ribulose 5-phosphate to the reaction mixtures caused a marked increase in the formaldehyde-dependent reduction of NAD+ or NADP+. In addition, the oxidation of [14C]formaldehyde to CO2, by extracts of Pseudomonas C, increased when D-ribulose 5-phosphate was present in the assay mixtures. The amount of radioactivity found in CO2, was 6;8-times higher when extracts of methanol-grown Pseudomonas C were incubated for a short period of time with [1-14C]glucose 6-phosphate than with [U-14C]glucose 6-phosphate. These data, and the presence of high specific activities of hexulose phosphate synthase, phosphoglucoisomerase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase indicate that in methanol-grown Pseudomonas C, formaldehyde carbon is oxidized to CO2 both via a cyclic pathway which includes the enzymes mentioned and via formate as an oxidation intermediate, with the former predominant.
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PMID:Oxidation of C1-compounds in Pseudomonas C. 19 17

The distribution and activities of several oxidative enzymes in various regions of the sebaceous glands of the domestic cat have been studied. The results obtained emphasize the outstanding importance of NADP-linked dehydrogenases for lipogenesis during sebum production. In particular, the reactions for glucose-6-phosphate dehydrogenase were very strong. Among the NAD-linked dehydrogenases investigated, lactate dehydrogenase showed strong activity in the peripheral cells of the sebaceous gland. The reactions for cytochrome oxidase and succinate dehydrogenase were weaker.
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PMID:Oxidative enzymes in the sebaceous glands of the domestic cat. 19 9

A colorimetric method is described for estimation of the adenilate kinase activity in blood serum; the method is based on coupling of adenilate- and creatine kinase reactions and on estimation of the amount of creatine formed. Adenilate kinase activity in blood serum, estimated by the method, was shown to increase 4-fold after removing of tourniquet with subsequent normalization within the next day. The same data were obtained using a spectrophotometric method for estimation of adenilate kinase based on NADP reduction in coupled reactions with hexokinase and glucose-6-phosphate dehydrogenase. An increase in creatine kinase activity in blood serum occurred later on after removing of the tourniquet; it was more distinct (8.5-fold) and maintained longer as compared with the increase in adenilate kinase activity.
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PMID:[Adenylate kinase and creatine kinase activity of rabbit blood serum following application of a tourniquet to the thigh]. 20 85

This paper reports the time course of development of the intramitochondrial cholesterol side-chain-cleavage activity, cytoplasmic NADP+-dependent isocitric dehydrogenase, malic enzyme and glucose-6-phosphate dehydrogenase during ovarian maturation, using as a model the immature rat ovary stimulated to develop with pharmacological doses of gonadotrophin. These enzymic activities were correlated with increases in ovarian content of DNA, cellular content of adenosin 3':5'-monophosphate, and the levels of plasma progesterone. The plasma progesterone concentrations followed closely the development of the [4-14C]cholesterol side-chain-cleavage which was mimicked by the cytoplasmic isocitric dehydrogenase; both enzymes increased in activity 28 times during the 6 days of this study. There was no correlation between adenosine 3':5'-monophosphate levels and cholesterol side-chain cleavage or progesterone plasma concentrations.
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PMID:Changes in enzyme activities during the artificially stimulated transition from follicular to luteal cell types in rat ovary. 20 54

Seven clonal human placental cell lines were established by transformation of human first-trimester placental cells with simian virus 40. These transformed cells synthesized native human choriogonadotropin (chorionic gonadotropin) (hCG) as well as the free alpha and beta subunits of hCG. The amount of native hCG synthesized by these cells was, however, lower than the amount of free beta subunit. (Both hCG and the beta subunit are detected by the radioimmunoassay for beta subunit, but only hCG is detected by the radioreceptor assay.) The alpha and beta subunits produced by these transformed placental cells were heterogeneous in size; the sizes of the predominant alpha and beta species, however, corresponded to those of urinary alpha and beta subunits, respectively. The seven cell lines transformed by simian virus 40 had chromosome numbers from the near diploid to the near tetraploid range. Fluorescent staining demonstrated the Y chromosome in all the transformants. Furthermore, B-type glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ 1-oxidoreductase; EC 1.1.1.49) was present in all seven lines. These characteristics ruled out possible HeLa contamination of the transformed lines. Regulation of the synthesis of alpha and beta subunits plus hCG in these transformed human placental cells differed from the regulation in choriocarcinoma cells.
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PMID:Establishment of clonal human placental cells synthesizing human choriogonadotropin. 20 73

Experiments were conducted on rabbits. A study was made of the activity of the redox enzymes--glucose-6-phosphate dehydrogenase (G-6-PDH), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), NAD-and NADP-diaphorases, cytochromeoxidase (CCO), alpha-glycerophosphate dehydrogenase (alpha-GPDH) in the supraoptic and paraventricular nuclei of the hypothalamus and the posterior lobe of the hypophysis under conditions of stimulation and removal of the superior cervical sympathetic ganglia. There was revealed a correlation between the activity of the tissue respiration enzymes (SDH, MDH, NAD- and NADP-diaphorase, CCO) and the functional condition of the hypothalamo-neurohypophysial neurosecretory system. However, the enzymes of the pentose-phosphate (G-6-PDH) and glycerophosphate shunt (alpha-GPDH) and also of the anaerobic way of oxidation (LDH) reacted nonspecifically on the induced effects.
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PMID:[Effect of removal and stimulation of the superior cervical sympathetic ganglia on the activity of oxidation-reduction enzymes in the neurosecretory cells of the anterior hypothalamus in rabbits]. 20 40

The first case of fructose-1,6-diphosphatase (FDPase) deficiency in Japan showed a decreased activity of glucose-6-phosphate dehydrogenase (G6PD) in the liver, white, and red blood cells. In the enzymatic study of G6PD which was partially purified from red cells, the following characteristics were observed in the enzyme of the patient. 1) The G6PD activity of the patient was reduced to 17% of normal, but no evidence of a hemolytic episode was found in his past and family history. 2) In the investigation of G6PD of the patient, no abnormalities were observed in its enzymatic parameters such as electrophoretic mobility, Km for G6P and NADP, Ki for NADPH, the utilization of 2-deoxy G6P and deamino NADP, heat-stability, and pH curves. 3) The dissociation constants of red blood cell G6PD for NADP and NADPH, which were obtained from the investigations on the reactivation of cold-inactivated G6PD at 37 degrees C, were about 3 times higher in the patient as compared to the values of the normal controls. Based on these findings, it might be concluded that the G6PD deficiency found in the red blood cells of this case of a FDPase deficiency is a unique variant, which could not be characterized by using only the method recommended by a World Health Organization (WHO) scientific group. Considering that the abnormality observed in the G6PD of this patient was a decrease in the affinity of the enzyme for its coenzymes, the dissociation constants for the coenzymes in reactivation process might be another important kinetic parameter in characterizing the G6PD deficiency.
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PMID:Deficiency of glucose-6-phosphate dehydrogenase found in a case of hepatic fructose-1,6-diphosphatase deficiency. 23 Apr 49

The effects of exposure of animals to 100% O2 and NO2 on the rate of prostaglandin metabolism by lung and kidney were studied in vitro. Exposure of guinea pigs to 100% O2 for 48 h inhibited the metabolism of prostaglandin F2 alpha by both NAD+- and NADP+-dependent prostaglandin dehydrogenase in lung, but had no effect on the metabolism in kidney. Succinate dehydrogenase, but not glucose 6-phosphate dehydrogenase, in guinea-pig lung was inhibited by exposure to 100% O2. Exposure to 46 p.p.m. but not 16 or 29 p.p.m. NO2 for 6 h inhibited guinea-pig lung prostaglandin dehydrogenase in vitro. The inhibition of pulmonary prostaglandin dehydrogenase by exposure to 100% O2 or to 49 p.p.m. NO2 was dependent on the duration of exposure, but returned to control values within 7 days after cessation of the exposure. The pulmonary transport system responsible for removing circulating prostaglandins from the blood was not affected by exposure to 100% O2 as measured by using the isolated perfused lung. Kinetic analysis of the inhibition of pulmonary prostaglandin dehydrogenase activity in guinea pig exposed to 100% O2 showed non-competitive inhibition with respect to both prostaglandin F2 alpha and NAD+, which suggests destruction or inactivation of the enzyme. Pulmonary prostaglandin dehydrogenase appears to be inhibited by exposure to oxidant gases, which may lead to elevated prostaglandin concentrations in the lungs or in the systemic circulation.
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PMID:Inhibition of pulmonary prostaglandin metabolism by exposure of animals to oxygen or nitrogen dioxide. 23 Aug 28


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