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 understand the anti-atherosclerotic mechanism of the steroid dehydroepiandrosterone (DHEA), the effect of DHEA on rat peritoneal macrophage superoxide generation was studied. Dehydroepiandrosterone (12.5 to 50 microM) inhibited digitonin-stimulated superoxide production in a dose-dependent manner, with 100% inhibition achieved at 50 microM. Dehydroepiandrosterone also inhibited macrophage superoxide production stimulated with phorbol myristate acetate, A23187 (calcium ionophore), sodium fluoride, and arachidonate. Dehydroepiandrosterone did not affect the activity of nicotinamide-adenine dinucleotide phosphate oxidase, which generates superoxide. Dehydroepiandrosterone inhibited superoxide formation in the presence of nicotinamide-adenine dinucleotide phosphate, potassium cyanide, and 2,4-dinitrophinal, suggesting that DHEA does not exert its effects by inhibiting glucose-6-phosphate dehydrogenase activity or mitochondrial respiration. Of the several steroids tested, epiandrosterone was as effective as DHEA in inhibiting macrophage superoxide production. Estrogen, androstenedione, and dihydroxytestosterone showed 25% inhibition, whereas pregnenolone, progesterone, testosterone, etiocholanolone, androstenediol, and DHEA-sulfate had minimal effect. The steroids cortisol and corticosterone had slight stimulatory effect. These results suggest that the anti-atherosclerotic effect of DHEA may be the result of inhibition of superoxide generation in macrophages.
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PMID:Inhibition of macrophage superoxide generation by dehydroepiandrosterone. 839 94

The endemic occurrence of favism in certain Mediterranean regions provided an investigative opportunity for testing in vivo the validity of claims as to the role of catalase in protecting human erythrocytes against peroxidative injury. Reduced activity of catalase was found in the erythrocytes of six boys who were deficient in erythrocytic glucose-6-phosphate dehydrogenase (G6PD) and who were studied while suffering hemolysis after ingesting fava beans. Activity of catalase was further reduced when their red blood cells were incubated with aminotriazole. In contrast, minimal reduction of catalase activity was found, both with and without incubation with aminotriazole, in erythrocytes of a G6PD-deficient boy who had ingested fava beans 7 days earlier and in erythrocytes of seven G6PD-deficient men with a past history of favism. These results confirmed earlier studies in vitro indicating that catalase is a major disposer of hydrogen peroxide in human erythrocytes and, like the glutathione peroxidase/reductase pathway, is dependent on the availability of reduced nicotinamide adenine dinucleotide phosphate (NADPH). The effect of divicine on purified catalase and on the catalase of intact G6PD-deficient erythrocytes was similar to the previously demonstrated effect on catalase of a known system for generating hydrogen peroxide. This effect of divicine strengthens earlier arguments that divicine is the toxic peroxidative component of fava beans.
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PMID:Active involvement of catalase during hemolytic crises of favism. 870 18

In previous studies a metabolic activation system (MAS) composed of Aroclor 1254-induced rat liver microsomes led to an apparent reduction of potato glycoalkaloid developmental toxicity in the frog embryo teratogenesis assay-Xenopus (FETAX). The reasons for this reduction were investigated in this study. The effect of the exogenous MAS on glycoalkaloid developmental toxicity was examined in two experiments in which a concentration series of alpha-chaconine was tested with a MAS with and without a reduced nicotinamide adenine dinucleotide (NADPH) generator system consisting of NADPH, oxidized nicotinamide adenine dinucleotide (NADP), glucose-6-phosphate (G6P) and glucose-6-phosphate dehydrogenase. The NADPH generator system and each of its individual components were tested at a single high concentration of alpha-chaconine to evaluate their potential effects on toxicity. The findings indicated that the protective effect of the MAS was not the result of detoxification by microsomal enzyme systems, but was caused by two components of the NADPH generator system, namely NADP and G6P. G6P was more protective of alpha-chaconine-induced toxicity than NADP at the concentrations tested. Thus, FETAX with a MAS must be performed with appropriate controls that take into account the possible interactions with individual components of the system.
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PMID:Protective effects of glucose-6-phosphate and NADP against alpha-chaconine-induced developmental toxicity in Xenopus embryos. 884 97

The investigations were carried out on 20 men (aged 32-48), hospitalized after lower extremity fractures, in whom no systemic diseases or disorders were found. The activity of glucose-6-phosphate dehydrogenase (G6P-DH), aldolase (A1), lactate dehydrogenase (LDH) and the concentrations of pyruvate, lactate, nicotinamide-adenine dinucleotide (NAD), nicotinamideadenine dinucleotide phosphate (NADP), adenosine-5'-triphosphate (ATP), adenosine-5'-diphosphate (ADP), adenosine -5'-monophosphate (AMP) and 2,3-diphosphoglycerate (2,3-DPG) in erythrocytes taken from patients were estimated. After a two-week hypokinesia G6P-DH, A1, LDH activities and ATP, ADP, AMP concentrations decreased, whereas other estimated parameters did not differ from the control levels. During a 30-day hypokinesia of patients with fractures of the lower extremity a transient decrease of erythrocyte metabolic activity was observed after two weeks. off
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PMID:Red blood cell metabolism in men during long term bed rest. 890 9

The dorsal root ganglion (DRG) neurons were classified in the rat on the basis of their metabolic enzyme properties as determined by quantitative analysis in histochemical staining. In particular, nicotinamide adenine dinucleotide-diaphorase (NADH-d) and alpha-glycerophosphate dehydrogenase (alpha-GPD) activities were examined on two serial sections from the same neurons in the lumbar (L4) DRG. The DRG neurons were classified into three groups based on the soma diameter distribution; small, intermediate and large size DRG neurons. The NADH-d activity showed a unimodal distribution in all size groups, while the alpha-GPD activity clearly showed a bimodal distribution in the intermediate and large size neurons, but not in the small size neurons.
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PMID:Metabolic properties of the sensory neurons in the rat dorsal root ganglion. 917 28

Mannose is an aldohexose component of a number of glycoproteins in cellular membranes and blood plasma. Free (unbound) mannose is a normal blood plasma constituent and its concentration is elevated in diabetes mellitus and chronic glomerulonephritis. We devised an enzymatic method for the determination of free mannose in which mannose is converted to glucose-6-phosphate and measured spectrophotometrically using glucose-6-phosphate dehydrogenase and nicotinamide adenine dinucleotide phosphate (NADP). Accumulation of reduced NADP in the assay was verified by spectral analysis and by finding rapid disappearance of absorbance at 340 nm on addition of glutathione reductase and oxidized glutathione into the reaction mixture. The method necessitates prior removal of glucose from the samples. This we accomplished using glucose-6-phosphate dehydrogenase and a surplus amount of NADP, followed by elimination of reduced NADP by acidification of the reaction mixture. The assays may be run in parallel for expediency. Concentration of free mannose in serum was 18.5 +/- 5.5 mumol/l in healthy fasting female adults. The analytical recovery was 90.2 +/- 10.2% and the between-run imprecision was 13.5% (18.5 +/- 5.5 mumol/l, mean +/- SD) and 10.4% (75.3 +/- 10.3 mumol/l). The assay showed rectilinearity up to 220 mumol/l, which covers the measuring range to which the mannose concentrations in normal and clinical samples may be expected to fall.
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PMID:Enzymatic determination of unbound D-mannose in serum. 936 94

This work evaluates the concept of a double enzyme-catalyzed microreactor using capillary electrophoresis (CE). Migrating in a capillary under electrophoresis conditions, plugs of substrate and two enzymes are injected separately in buffer and allowed to react. Extent of reaction and product ratios were subsequently determined by CE. This concept is demonstrated using two model systems: the conversion of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) and adenosine monophosphate (AMP) by hexokinase (HK, EC 2.7.1.1) and apyrase (APY, EC 3.6.1.5), respectively, in the conversion of glucose to glucose-6-phosphate and inorganic phosphate, respectively, and the conversion of nicotinamide adenine dinucleotide, reduced form (NADH), to nicotinamide adenine dinucleotide (NAD) and back to NADH by lactate dehydrogenase (LDH, EC 1.1.1.27) and glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), respectively, in the conversion of pyruvate to lactate and glucose-6-phosphate (glc-6-P) to 6-phosphogluconate, respectively. These procedures illustrate the use of the capillary as a double microreactor and the ease of quantitation of reaction products under conditions of electrophoresis.
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PMID:Double enzyme-catalyzed microreactors using capillary electrophoresis. 955 95

Ingestion of strong oxidant substances may result in acquired methemoglobinemia, a clinical condition in which the oxidized blood hemoglobin is incapable of delivering oxygen to the tissues, and the patient becomes cyanotic. Traditional first-line therapy consists of infusion of methylene blue, whose action depends on the availability of reduced nicotinamide adenine nucleotide phosphate (NADPH) within the red blood cell (RBC). Some patients, particularly those who are deficient in glucose-6-phosphate dehydrogenase (G6PD), will not benefit from methylene blue. In these patients, and in some patients who have ingested very strong oxidants, methylene blue may also precipitate Heinz body hemolytic anemia. We present a case of severe, acquired methemoglobinemia in a 26-month-old, 9.8-kg boy with G6PD deficiency. He was cyanotic, in respiratory failure, intubated in a pediatric intensive care unit. In typical fashion, he did not respond to methylene blue. Manual exchange of two whole blood volumes, performed over 4 1/2 hr, also failed to resolve his severe methemoglobinemia. An automated RBC exchange (1.3 RBC volume), lowered his methemoglobin content from 31.8% to 7% in a single 40-min procedure. Thereafter his methemoglobin level continued to decrease rapidly and spontaneously. He was discharged home 2 days later, with 0.4% methemoglobin. To our knowledge, this is the first report to demonstrate the (potentially superior) effectiveness of automated RBC exchange for treatment of patients with high-risk acquired methemoglobinemia, that is, those with G6PD deficiency or who have ingested strong oxidants.
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PMID:Treatment of high-risk, refractory acquired methemoglobinemia with automated red blood cell exchange. 959 Apr 95

To better understand the role of nicotinic acid and nicotinamide in the regulation of the oxidative stress response, we measured the levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glucose-6-phosphate dehydrogenase (G6PD) mRNA in Jurkat cells treated with these NAD+ precursors. We used a modified nonradioactive Northern blot method and detected the mRNA using 18-mer digoxigenin (DIG)-labeled oligonucleotides as probes. We observed increased levels of the mRNAs for the two enzymes in treated cells. Our findings suggest that the NAD+ precursors may protect against oxidative stress and DNA damage by up-regulating the stress response genes GAPDH and G6PD.
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PMID:The NAD+ precursors, nicotinic acid and nicotinamide upregulate glyceraldehyde-3-phosphate dehydrogenase and glucose-6-phosphate dehydrogenase mRNA in Jurkat cells. 1008 68

The morphological pattern of several enzymes (succinic dehydrogenase--SDH, glucose-6-phosphate dehydrogenase--G6PDH and lactic dehydrogenase--LDH) was evaluated in normal dog eyes. Special attention was paid to the uveo-scleral tissue. Cryostatic sections of dog eye were stained with toluidine blue for the recognition of the microanatomical details or with histoenzymatic methods for SDH, G6PDH and LDH activities using sodium succinate, glucose-6-phosphate and sodium lactate as substrates respectively, nicotinamide adenine dinucleotide (NAD) as a reducing agent and sodium nitro-blue-tetrazolium as a colouring substance. A moderate positive reaction for SDH and a strong positive reaction for LDH were observed in the uveoscleral tissue, while G6PDH gave negative staining. Some considerations regarding a possible active role of these enzymatic activities to the aqueous humor outflow are suggested.
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PMID:Uveoscleral outflow in dog's eye: role of several enzymes. 1067 68


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