Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.2 (NQO1)
 6,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The method of visual quantitative estimation was employed to determine the index of enzymes activity in embryonal cells cultures infected with Rous virus. In early terms (1-7 days after infection) a moderate production of diformazane was noted in the presence of glucoso-6-phosphatiosomerase, phosphoglucomutase, pyruvatoxidase, NAD. H2- and NADP. H-2-diaphorase, other enzymes showing no distinquishable deviations in the activity, as compared with the normal culture. In later terms (13-27 days) during the proliferation of the transformed cells there was found an increased level of the glycolysis enzymes activity, pentose cycle, hydrolysis of ortho-phosphoric acid monoethers and reduced lemon acid cycle and tissue respiration. Cytoplasmatic vacuoles formed in the transformed cells seem to represent hypertrophic lysosomes and phagolysosomes.
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PMID:[Quantitative cytochemical detection of enzymes in cultured cells following infection with Rous virus]. 17 56

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 authors have studied the enzymhistochemical and ultrastructural pictures of tenocytes of adult human tendons. High succinate dehydrogenase, cytochrome oxidase, TPN-diaphorase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity were found, as indicated both oxidativ, anaerobic and pentose-phosphate shung activity. Phosphorylase and glutamate dehydrogenase activity was medial, lipase and alcaline phosphatase activity was slight. In tenocytes well developed rough endoplasmic reticulum and GOLGI apparatus, large amount of free ribosomes were found.
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PMID:Histochemical and ultrastructural study of adult human tendon. 23 84

Quantitative cytochemical techniques have been employed in a study of some of the acute effects of low doses (0.01----1 mU/liter) of TSH on the metabolism of guinea pig thyroid segments maintained in nonproliferative organ culture. The enzymes involved in the synthesis of NADP+ (NAD+ kinase), its reduction by the pentose-shunt (glucose 6-phosphate dehydrogenase), and its reoxidation both by the microsomal electron chain (diaphorase activity) and by participation in other cellular processes, have been examined. The effect of TSH on peroxidase activity has also been studied. After 10 min stimulation with TSH (1 mU/liter) there was a 60% increase in NAD+ kinase activity which preceded changes in the microsomal reoxidation of NADPH (up 33% by 30 min). There were no changes in the activity of glucose 6-phosphate dehydrogenase. There was a sustained rise in peroxidase activity which reached 129% over control after 30 min. This is the first in vitro demonstration of an acute stimulation of peroxidase and kinase activities by physiological concentrations of TSH. NADPH reoxidation after stimulation with TSH was such that the ratio of NADPH reoxidized via the microsomal respiratory pathway (diaphorase, hydrogen pathway 1) relative to that available for cytosolic utilization (hydrogen pathway 2) increased compared to the unstimulated controls. We suggest that increased NADP+ production (via NAD+ kinase activity) and the preferential shuttling of the NADPH for reoxidation via the microsomal respiratory pathway, coupled with greatly stimulated peroxidase activity, may be important regulators of the control of thyroglobulin iodination and hence thyroid hormone production.
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PMID:Acute stimulation of thyroidal NAD+ kinase, NADPH reoxidation, and peroxidase activities by physiological concentrations of thyroid stimulating hormone acting in vitro: a quantitative cytochemical study. 284 14

Quantitative histochemical assays of several enzymes (succinic, lactic, beta-hydroxybutyrate, alpha-glycerophosphate, and glucose-6-phosphate dehydrogenases, NAD diaphorase, and phosphorylase) in the myocardium of persons who had died suddenly with postinfarctional cardiosclerosis have failed to reveal any changes specific for this patient group. Direct correlations were established between the enzyme activities assayed, on the one hand, and the extent of myocardial hypertrophy and the signs of chronic heart failure, on the other. The activities of beta-hydroxybutyrate dehydrogenase and glucose-6-phosphate dehydrogenase, which are involved in fatty acid utilization and in the pentose phosphate pathway, were elevated in cases of moderate hypertrophy, as were those of all redox enzymes in cases of strongly marked hypertrophy, although they were reduced in cases with signs of chronic cardiac failure despite the presence of considerable myocardial hypertrophy. Areas of acute myocardial ischemia were discovered in 45% of the cases.
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PMID:[Histochemical study of the enzyme activity of the myocardium of sudden death victims with postinfarct cardiosclerosis]. 296 Feb 98

Osteogenesis of the body of the mandible in embryonic and neonatal rats was studied histologically and by histochemistry to determine the role of Meckel's cartilage in bone formation. Meckel's cartilage showed intense activity of lactate dehydrogenase and NADH2-diaphorase and weak activity of acid phosphatase, indicating a functioning citric acid cycle, pentose phosphate shunt and a capacity for anaerobic metabolism. The activity of these enzymes declined after hypertrophy of Meckel's cartilage. Alkaline phosphatase was the major enzyme of mineralising mandibular osteoid and was present in the osteoblasts and osteoprogenitor cells but not in Meckel's cartilage. After the differentiation of Meckel's cartilage and intramembranous bone, Meckel's cartilage supported mandibular bone formation by endochondral ossification in the anterior part of the mandible.
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PMID:Enzyme histochemical analysis of Meckel's cartilage. 325 49

Oxygen and glucose consumption and lactate production of the peritoneal membrane and intra-abdominal adhesions were measured in rats after a single intra-peritoneal colloidal silica injection. Enzyme histochemical studies were made of lactate dehydrogenase, succinate dehydrogenase, NADH2-diaphorase, NADPH2-diaphorase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, acid phosphatase, leucylaminopeptidase and alkaline phosphatase in the peritoneal membrane. Anaerobic glycolysis comprises 47% of the total glucose consumption in the the normal peritoneum. Glucose consumption and lactate production of the peritoneal membrane increased sharply in the early phase of silica-induced peritonitis and stayed at a high level for a week indicating an enhanced anerobic metabolism. Oxygen and aerobic glucose consumption increased more slowly than anaerobic glucose consumption and reached their maxima 1 week after silica injection, indicating that the rate of aerobic metabolism is also higher in chemical peritonitis than in the controls. On the other hand, glucose consumption and lactate production increased in a parallel fashion in adhesions and in the peritoneum in the early phase of peritonitis. However, the maximum and later levels were less in adhesions than in the peritoneum. In the enzyme histochemical study high activities of enzymes indicating anaerobic energy metabolism and metabolism via the pentose phosphate shunt were seen in cells of the peritoneal membrane during the early phase of peritonitis. No activity was identified in enzymes indicating aerobic energy metabolism and increased catabolism before the end of the first week.
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PMID:Energy metabolism of the peritoneal membrane in silica-induced peritonitis. A biochemical and enzyme histochemical study. 625 64

Kluyveromyces lactis mutants defective in the glycolytic enzyme phosphoglucose isomerase are able to grow in glucose media and to produce ethanol, but they depend on a functional respiratory chain and do not grow in glucose-antimycin media. We postulate that this is due to the necessity of reoxidizing, in the mitochondria, the NADPH produced by the pentose phosphate pathway, which may be highly active in these mutants in order to bypass the blockade in the phosphoglucose isomerase step. This oxidation would be mediated by a cytoplasmic-side mitochondrial NAD(P)H dehydrogenase that would pass the electrons to ubiquinone. Data supporting this hypothesis are provided.
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PMID:Reoxidation of the NADPH produced by the pentose phosphate pathway is necessary for the utilization of glucose by Kluyveromyces lactis rag2 mutants. 865 69

Dopamine (DA) is oxidized to the neurotoxic prooxidant species H2O2, OH., and DA quinones. We tested whether dimethyl fumarate (DMF), an electrophile shown to induce a pleiotropic antioxidant response in nonneuronal cells, could reduce the toxicity of DA metabolites in neural cells. Treatment of the N18-RE-105 neuroblastoma-retina hybridoma cell line with 30-150 microM dopamine led to cell death within 24 h, which increased steeply with dose, decreased with higher plating density, and was blocked by the H2O2-metabolizing enzyme catalase. Pretreatment with DMF (30 microM, 24 h) significantly attenuated DA and H2O2 toxicity (40-60%) but not that caused by the calcium ionophore ionomycin. DMF treatment also elevated total intracellular GSH and increased activities of the antioxidant enzymes quinone reductase (QR), glutathione S-transferase (GST), glutathione reductase, and the pentose phosphate enzyme glucose-6-phosphate dehydrogenase. To assess the protective efficacy of QR and GST, a stable cell line was constructed in which these enzymes were overexpressed. Cell death in the overexpressing line was not significantly different from that in a cell line expressing normal QR and GST activities, indicating that these two enzymes alone are insufficient for protection against DA toxicity. Although the relative importance of a single antioxidant enzyme such as QR or GST may be small, antioxidant inducers such as DMF may prove valuable as agents that elicit a broad-spectrum neuroprotective response.
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PMID:Activation of endogenous antioxidant defenses in neuronal cells prevents free radical-mediated damage. 964 52

Photoautotrophically grown cells of the cyanobacterium Synechocystis sp. PCC 6803 wild type and the Ins2 mutant carrying an insertion in the drgA gene encoding soluble NAD(P)H:quinone oxidoreductase (NQR) did not differ in the rate of light-induced oxygen evolution and Photosystem I reaction center (P700+) reduction after its oxidation with a white light pulse. In the presence of DCMU, the rate of P700+ reduction was lower in mutant cells than in wild type cells. Depletion of respiratory substrates after 24 h dark-starvation caused more potent decrease in the rate of P700+ reduction in DrgA mutant cells than in wild type cells. The reduction of P700+ by electrons derived from exogenous glucose was slower in photoautotrophically grown DrgA mutant than in wild type cells. The mutation in the drgA gene did not impair the ability of Synechocystis sp. PCC 6803 cells to oxidize glucose under heterotrophic conditions and did not impair the NDH-1-dependent, rotenone-inhibited electron transfer from NADPH to P700+ in thylakoid membranes of the cyanobacterium. Under photoautotrophic growth conditions, NADPH-dehydrogenase activity in DrgA mutant cells was less than 30% from the level observed in wild type cells. The results suggest that NQR, encoded by the drgA gene, might participate in the regulation of cytoplasmic NADPH oxidation, supplying NADP+ for glucose oxidation in the pentose phosphate cycle of cyanobacteria.
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PMID:Reduction of photosystem I reaction center in DrgA mutant of the cyanobacterium Synechocystis sp. PCC 6803 lacking soluble NAD(P)H:quinone oxidoreductase. 1517 Mar 83


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