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)

In a detailed study focused on the methodological problems in dehydrogenase histochemistry [e.g., fixation, diffusion of enzymes and of reduced inermediates, conversion of NADPH and NADP to NADH and NAD, respectively, penetration of tetrazolium salt and formazan substantivity, 'nothing dehydrogenase' reaction, use of exogenous CoQ10 and of flavoprotein substitute (PMS)], the distribution and activity of succinate dehydrogenase, NAD(P)H-tetrazolium reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase (H and M types), and of L-glutamate dehydrogenase (E.C.1.4.1.2 and E.C.1.4.1.3) have been investigated in the rat cerebellum. It was evident from the study that reliable results could only be obtained if all the aforementioned factors had been considered. The image of actual concentration of SDH in the neuropil of the molecular layer could only be recorded by adding CoQ10, while other structures exhibited greater balance between SDH and endogenous mitochondrial CoQ. Contrary to previous studies, a reversed localization of the activity of G-6-PDH and LDH was noticed. The elements of molecular and Purkinje layers were rich in G-6-PDH, while the granular layer was nearly depleted. The actual level of LDH could only be recorded if NADH-tetrazolium reductase was bypassed with PMS. The H and M types of LDH coexisted in the three cortical layers, the H type being prevalent and the M type attaining its highest level in synaptic glomeruli followed by the structures of the molecular layer and the Purkinje cells. High activity of GDH was noticed in Bergmann glia followed by synaptic glomeruli, while most other structures showed weak to moderate activity. The two GDH types coexisted in all structures showing activity, except for Bergmann cells, which only showed presence of the E.C. 1.4.1.3 type. Furthermore, Bergmann glia was exceptional by showing no activity of SDH and LDH, but strong activity of G-6-PDH and NADPH-tetrazolium reductase. The granular cells were exceptional by showing weak or no activity of all enzymes in question.
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PMID:Methodological aspects of the histochemical localization and activity of some cerebellar dehydrogenases. 66 87

Miscroscopic changes in the liver tissue of mice became detectable 42 hours after the administration of gricine through the appearance of porphyrins in the plasma of hepatocytes marked by the enlargement of their volume, nuclei, and nucleoli. 72 hours after gricine, porphyrins were also found in the lumina of capilary bile ducts and hepatic ducts. This was accompanied by dispersion extinction of hepatocytes and pigment accumulation in the plasma of Kupffer's cells. There was histochemically proved increased activity of alkaline and acidic phosphatase, G6PDH, NADH and NADPH tetrazolium reductase. Under electron microscopy, the porphyrins showed crystalline structure, rotated the plane of polarized light, and were marked by red fluorescence.
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PMID:[Morphological changes in liver tissue in experimental porphyria]. 69 8

The activities of twelve enzymes were measured in crude extracts from cells of Escherichia coli K-10 grown aerobically or anaerobically in a defined medium in the presence or absence of nitrate. The activities of isocitrate dehydrogenase, aconitate hydratase, 2-oxoglutarate dehydrogenase, malate dehydrogenase, malic enzyme, and D-lactate dehydrogenase (NAD+-independent) were found to be higher in cells grown in nitrate respiration than in those in fermentation, but lower than in those in respiration. This finding may explain the incomplete oxidation in nitrate respiration and, on the other hand, suggests the operation of the tricarboxylic acid even under these conditions. The activities of succinate dehydrogenase and alcohol dehydrogenase in relation to the formation of fermentation product were as high in cells grown in fermentation as in those in respiration and were low in those in nitrate respiration. However, that ratio of the activities in the latter case to the activities in respiration was the same as the ratio for most enzymes in the tricarboxylic acid cycle. The level of lactate dehydrogenase (NAD+-dependent) was not affected by nitrate respiration but its activity in the extract was inhibited by nitrate and nitrite. The absence of lactate in the anaerobic culture with nitrate may be due to this inhibition as well as NADH oxidation by nitrate. Levels of glucose-6-phosphate dehydrogenase and glutamate dehydrogenase were not altered by the growth conditions and that of pyruvate dehydrogenase was low only in cells grown in fermentation.
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PMID:Effect of nitrate reduction on the enzyme levels in carbon metabolism in Escherichia coli. 77 52

In the presented study the influence of freezing and freeze-drying on enzyme activity is described. Attention is paid to 16 enzymes which can be used for quantitative enzyme histochemical techniques. With the exception of succinate dehydrogenase only, no significant inactivation during freezing and freeze-drying procedures could be demonstrated with lactate dehydrogenase, malate dehydrogenase (NAD+), malate dehydrogenase (decarboxylating) (NADP+), isocitrate dehydrogenase (NADP+), glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, NADH-oxydoreductase, mitochondrial glycerol-3-phosphate dehydrogenase, cytochrome c oxidase, phosphoglucomutase, glucosephosphate isomerase, glucose-6-phosphatase, acid phosphatase, beta-glucuronidase and non specific aryl esterase. Therefore, the results supply a sound foundation for those quantitative enzyme histochemical techniques in which tissue specimens are frozen or frozen-dried before enzyme estimations are performed.
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PMID:The influence of freezing and freeze-drying of tissue specimens on enzyme activity. 87 Apr 61

Two freshwater bacteria, a Pseudomonas sp. and a Spirillum sp., were grown in continuous culture under steady-state conditions in L-lactate-, succinate-, ammonium- or phosphate-limited media. In Pseudomonas sp., NAD-independent and NAD-dependent L-lactate dehydrogenases, aconitase, isocitrate dehydrogenase and glucose 6-phosphate dehydrogenase activities increased up to 10-fold as the dilution rate (D) was decreased from 0.5 to 0.02 h-1, regardless of whether the growth-limiting nutrient was carbon, ammonium or phosphate. In contrast, 2-oxoglutarate dehydrogenase and succinate dehydrogenase activities were not influenced by D, and NADH oxidase activity increased with D. Spirillum sp. gave different results in some respects, but it also exhibited an increase in the activity of several enzymes at low D values. Such increases may emanate from release of catabolite repression, and catabolite repressors for the five enzymes in Pseudomonas sp. showing such increases are probably compounds of carbon, nitrogen and phosphorus. It is likely that increased enzyme syntheses in low D cultures represent the normal physiological state for bacteria in aquatic environments where growth occurs slowly under nutrient limitations. Such increases probably permit a more effective utilization of nutrients present at sub-saturating concentrations.
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PMID:Influence of dilution rate on enzymes of intermediary metabolism in two freshwater bacteria grown in continuous culture. 95 May 55

Enzyme-histochemical methods were used to study the metabolic activity of specialized ependyma of the ventrolateral walls and floor of the third ventricle in young male and female rats during the "critical period" of sexual differentiation of the hypothalamus (one week after birth). Histochemical tests were conducted for glutamic dehydrogenase, lactic dehydrogenase, glucose-6-phosphate dehydrogenase, glycerophosphate dehydrogenase and NADH2-dehydrogenase. Enzyme activity was judged by cytospectrophotometry. All the data were treated statistically. It was found that the specialized ependyma of the ventrolateral wall and floor of the third ventricle (median eminence) in rats differed in their enzyme behaviour in males and females during the "critical period" of sexual differentiation of the hypothalamus. At the level of the arcuate nucleus (alpha2-tanycytes) and the medial part of the median eminence (beta2-tanycytes) the ependyma was characterized by similar indices of metabolic activity in males and females in the decisive terms of the "critical period" (days 3, 5, and 7). On day 5 metabolic activity of these cells was reduced both in the males and in the females. Prominent sexual differences in the intensity of the enzyme reactions studied were noted in the ependyma of the lateral parts of the median eminence (beta1-tanycytes) in the "critical period". On day 5 metabolic activity of beta1-tanycytes was reduced in males and increased in females. It is suggested that these differences are caused by the receptor nature of beta1 tanycytes and suggest their implication in the mechanisms of sexual differentiation of hypothalamus.
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PMID:Morphological aspects of the hypothalamic-hypophyseal system. VI. The tanycytes: their relation to the sexual differentiation of the hypothalamus. An enzyme-histochemical study. 99 Dec 50

The influence of Serpasil (Ciba) on histological activities of dehydrogenases and reductases as well as on PAS-positive substances in the small intestine of white rats has been studied. It has been demonstrated that a decrease in the succinic, lactic and glucose-6-phosphate dehydrogenase activities as well as in the NADH and NADPH tetrazole reductase activities occurs in the rat's small intestine epithelial cells after the administration of Serpasil. However, a considerable intensification in the reactions to PAS-positive substances in the mucous cells and an increase in the amount of these cells has been observed.
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PMID:The effect of hypotensive drugs (Serpasil) on the histochemical reactions in the small intestine of white rats. 118 94

Investigations on the effect of reserpine on the histochemical reactions to some dehydrogenases (succinic, lactic, glucose-6-phosphate dehydrogenase) as well as to NADH and NADPH tetrazole reductases in the seminiferous epithelium of white rats have been performed. A weakening of the dehydrogenase activities has been mainly observed in the young cells of seminal epithelium i, e. in spermatogone and spermatocytes. The changes in histoenzymatical reactions caused by reserpine may be the evidence of the inhibition of oxidation-reduction processes in the studied reproductive cells.
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PMID:The activity of some dehydrogenases and NADH and NADPH tetrazole reductases in the seminiferous epithelium of reserpinized white rats. 123 10

The concentration of 2,3-diphosphoglycerate, and the activities of the enzymes hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glutathione reductase and NADH-dependent methaemoglobin reductase in the erythrocytes of newborn and adult sheep were investigated. All the enzyme activities and the concentration of 2,3-diaphosphoglycerate were found to be significantly greater in the erythrocytes of newborn lambs than in those of adult sheep.
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PMID:Postnatal changes in the levels of 2,3-diaphosphoglycerate, reduced glutathione and some enzyme activities in the erythrocytes of lambs. 126 64

1. NADPH-specific mitochondrial enoyl-CoA reductase can be assayed by a sensitive radioactive test, employing tritium-labelled NADPH, synthesized in a prefixed reaction from D-[1-3H]-glucose via the hexokinase and glucose-6-phosphate dehydrogenase reactions. 2. Liver, kidney cortex, heart muscle, skeletal muscle, brown adipose tissue, brain cortex, and aortic intimal tissue are investigated concerning chain lengths specificity of the chain elongation and the enoyl-CoA reductase. Medium-chain acyl-CoA compounds prove to be the best primers for the chain elongation. Enoyl-CoA reductases still show large incorporation rates with hexadecenoyl-CoA. 3. The differences in the chain lengths specificity of the chain elongation and enoyl-CoA reductase can be explained by the inhibitory effect of long-chain acyl-CoA derivatives on the 3-hydroxyacyl-CoA dehydrogenase. 4. The nucleotide specificity in the different tissues reveals two types of chain elongation: In addition to liver and kidney cortex, mitochondria of brown adipose tissue need NADH + NADPH for optimal chain elongation, whereas heart muscle, skeletal muscle and aortic intimal mitochondria only need NADH. 5. Different physiological roles are proposed for the two types. The "heart type" may be of importance in the conservation of reducing equivalents or acetate units in the anaerobic state, the "liver type" may play a role in the transfer of hydrogen from NADPH to the respiratory chain. In addition, the mitochondrial chain elongation may serve as bypass of the first part of the respiratory chain.
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PMID:On the mechanism of malonyl-CoA-independent fatty-acid synthesis. Different properties of the mitochondrial chain elongation and enoylCoA reductase in various tissues. 127 59


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