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)

Muscles of the lower legs of rats given 25% ethanol in water ad libitum for up to 9.5 months were studied using histological, histochemical and electrophysiological techniques. Ethyl alcohol was substituted for about 20% of the total calorific input of the animals. The observations were compared with the structure of the gastrocnemius muscle of five alcoholics with clinical neuropathy. Fibrillation potentials and angulated atrophic fibers were observed in the muscles of animals on alcohol for 9.5 months. No fiber type grouping was present. There was also phagocytosis of the muscle fibers and changes in their internal structure, as reflected by the distribution of NADH-diaphorase. The observed muscle changes in the alcoholics and those in the experimental animals on alcohol differed mainly quantitatively, the only exception being the presence of fiber type grouping in the biopsies from the alcoholics.
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PMID:Myopathy associated with chronic alcohol drinking. Histological and electrophysiological study. 14 76

Biopsies from vastus lateralis muscle of male patients suffering from chronic ethanol abuse were studied with regard to histochemical reactions of ATPase and NADH-diaphorase; enzymatic activities of triosephosphate dehydrogenase (TPD), lactate dehydrogenase (LD), and cytochrome c oxidase (cytox); content of ATP, creatine phosphate, and glycogen; and volume fractions of fat, mitochondria, and fibrillar and extrafibrillar space. The results were compared with those from controls without known abuse of ethanol. The relative numbers of fibers were the same in two groups, but the size of the fast-twitch-glycolytic (white) fibers was diminished in the alcoholic group. The activities of TPD and LD were diminished in skeletal muscle of the alcoholics. This is most probably caused by the reduced amount of fast-twitch-glycolytic tissue, as there was a good correlation between this amount and the activity of the two enzymes. The activity of cytox was slightly lower in muscle of the alcoholics than in that of the controls. The volume fraction of mitochondria was lower in the alcoholic group than in the control group. Volume fractions of fat and fibrillar and extrafibrillar space were equal in the two groups. No significant differences were found in the amount of glycogen and ATP in the muscle of the two groups. However, the content of creatine phosphate is higher in the alcoholic group than in the control group.
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PMID:Effects of chronic ethanol abuse on structure and enzyme activities of skeletal muscle in man. 17 13

Intermittent inhalation of 300 ppm of xylene vapour 6 h daily for 2 weeks caused a marked accumulation of the solvent in the perirenal fat. Simultaneous ethanol ingestion reduced the solvent load significantly although the perirenal xylene concentration increased in both test groups between the first and second week of exposure. Xylene inhalation enhanced hepatic and renal ethoxycoumarin 0-deethylase activity about 1.5-fold. The combination of inhaled xylene and peroral ethanol showed a markedly potentiated effect on microsomal ethoxycoumarin 0-deethylase activity especially in the kidneys. The enhanced monooxygenase activity was compatible with the decreased body solvent burden. Therefore, simultaneous ethanol intake might significantly modify the toxicological hazard in xylene exposure. Slightly increased proteolysis was detected in brain of animals in the xylene-ethanol experiment after the second week. Brain RNA content decreased after 2 weeks of exposure in the ethanol consuming animals. Xylene inhalation enhanced cerebral DT-diaphorase activity in both groups after 2 weeks of exposure. Ethanol intake also potentiated the behavioural effects caused by the solvent inhalation.
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PMID:Biochemical and toxicological effects of short-term, intermittent xylene inhalation exposure and combined ethanol intake. 73 90

An isolation procedure of mitochondrial menadione reductase from rat liver using an ethanol-ether extraction for solubilization of the enzyme is described. The enzyme was purified 930-fold. The molecular weight of mitochondrial menadione reductase is 62,000. According to spectroscopic and enzymic analysis the prosthetic group of the enzyme was identified as FAD. Mitochondrial menadione reductase is inhibitied by dicumarol and p-chloromecuribenzoate. The enzyme is characterized by a group substrate specificity towards quinones. A high catalytic activity of menadione reductase towards 4-aniline-5-methoxy-1,2-benzoquinone (AMOBQ), and 4-N-(p-sulfoanilino)-5-methoxy-1,2-benzoquinone (AMOBQS) as acceptors was demonstrated. It was shown that the reduction of these orto-benzoquinones by NAD(P) H follows the "ping-pong" kinetics. The kinetic constants for NAD(P)H,AMOBQ and and AMOBQS were determined.
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PMID:[Properties and reaction mechanism of mitochondrial menadione reductase]. 102 99

Rats fed an ethanol-containing diet for 4 weeks showed a 3- to 5-fold increase over isocalorically pair-fed controls with respect to cytosolic NAD(P)H-quinone oxidoreductase (NQOR) (E.C.1.6.99.2) with both menadione and dichlorophenol-indophenol as substrates. Rates of NAD(P)H-dependent p-nitrosophenol (pNSP) reduction catalyzed by rat liver cytosolic fractions were increased 1.5- to 2-fold upon pretreatment of the animal with ethanol. NQOR contributed almost exclusively to the NADPH-dependent C-nitrosoreductase activity in cytosol as judged by the strong inhibition of the reaction by dicoumarol. In contrast, NADH-dependent C-nitrosoreductase activity was inhibited 70-80% by pyrazole and thus may be attributed mainly to alcohol dehydrogenase(s). Highly purified rat liver cytosolic NQOR catalyzed the NADH- and NADPH-dependent reduction of pNSP to p-aminophenol. We therefore suggest that ethanol ingestion enhances the reduction of the C-nitrosoaromatics formed upon cytosolic metabolism of arylamines or nitroarenes by two mechanisms. Increased NADPH-dependent reduction is mediated by the induction of cytosolic NQOR while an NADH-dependent pathway responds to the increased availability of reduced cofactor upon ethanol ingestion and involves mainly the alcohol dehydrogenase-mediated reduction of such compounds.
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PMID:Role of cytosolic NAD(P)H-quinone oxidoreductase and alcohol dehydrogenase in the reduction of p-nitrosophenol following chronic ethanol ingestion. 158 50

We have tested an ethanol reagent strip developed at the Addiction Research Foundation of Ontario. Alcohol dehydrogenase and nicotinamide adenine dinucleotide, in the presence of pyrazole, react with ethanol to yield acetaldehyde plus reduced nicotinamide adenine dinucleotide. The latter reduces iodonitrotetrazolium chloride in the presence of diaphorase, generating an intense red color. The rate of color development is proportional to the concentration of ethanol. Color is compared at a specific time against a calibrated color scale ranging from green (negative) to red, representing alcohol concentrations of 0, 25, 50, 100, 200, and 400 mg/dl (0-0.4%; 0-87 mmol/liter). We were able to interpolate the color observed between the calibrated blocks. When tested on urine, serum/plasma, and saliva, ethanol concentration determined by the reagent strip correlates well with ethanol concentration as determined by gas chromatography or by automated enzymatic analysis (r = 0.92-0.98, p less than 0.001; slope 0.83-1.16). The reagent strip was shown to be used appropriately by nonexperienced individuals following a 1-min explanation (reagent strip values, r = 0.92; p less than 0.001, slope = 0.97, versus gas chromatography). The reagent strip does not react with methanol (wood alcohol), isopropanol (rubbing alcohol), and ethylene glycol (antifreeze) often found in accidental poisonings. In 379 clinical samples obtained without exclusion criteria from 12 hospital emergency rooms and a liver clinic, the sensitivity of the reagent strip in detecting ethanol was 98%. Specificity was 99%. The reagent strip was found to have virtually unlimited stability under refrigeration (4 degrees C) and to be stable for 3 to 4 months at room temperature (22-23 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)
Alcohol Clin Exp Res 1992 Apr
PMID:Characteristics of a new urine, serum, and saliva alcohol reagent strip. 159 May 43

NAD(P)H:(quinone-acceptor)oxidoreductase (QAO), previously known as DT-diaphorase, catalyzes the reduction of quinones to hydroquinones. Enhanced activity of the enzyme has been suggested to protect cells against the cellular toxicity and carcinogenicity of quinones, but may activate some cytotoxic anti-tumor quinones. Cytosolic levels of QAO, carbonyl reductase (CR) and total quinone reductase activity have been measured in normal and tumorous human tissues. QAO was the major component of the total cytosolic quinone reductase activity in all the tissues investigated. CR represented 10 to 28% of the total cytosolic quinone reductase activity in normal tissue. Normal tissue QAO was high in the stomach and kidney, and lower in the lung, liver, colon and breast. Primary tumor from lung, liver, colon and breast had elevated levels of QAO compared to normal tissue, while tumor from kidney and stomach had lower levels. CR was not significantly altered in tumor tissue, except in the case of lung and colon tumor which showed an increase compared to normal tissue. A major determinant of the variability of human lung tumor QAO was the cigarette-smoking history of the donor. Non-smokers and past smokers had high levels of tumor QAO compared to normal tissue. Smokers had levels of tumor QAO that were not significantly different from those of normal tissue QAO. Smokers had a small increase in normal lung QAO compared to non-smokers. Alcohol use was associated with an increase in lung tumor QAO but had no effect on QAO in normal lung. The function of QAO in tumors is not known but the elevated activity of QAO in some tumors and the apparent depressant effect of smoking could influence the response of these tumors to quinone drugs or toxic agents that are metabolized by QAO.
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PMID:Cytosolic NAD(P)H:(quinone-acceptor)oxidoreductase in human normal and tumor tissue: effects of cigarette smoking and alcohol. 230 29

Electrochemical kinetic measurements were carried out for electron-transfer between NADH and the oxidized forms of mediators (ferrocenylmethanol (FMA), ferrocenyl-1-ethanol (FEA), N,N,N',N'-tetramethylphenylenediamine (TMPD), Co(Phen)2+(3) and Fe(CN)4-(6)) catalyzed by diaphorase (NADH: acceptor oxidoreductase, EC 1.6.99.-) purified from Bacillus stearothermophilus. Cyclic voltammograms for the mediators with excess NADH in the presence of diaphorase gave steady-state currents. The quantitative analysis of the dependence of the current on the mediator concentration yielded a Michaelis constant (Km) and molecular activity (ko), which are difficult to determine by the conventional spectrophotometric method. Small Km and large ko values were observed for the oxidized forms of FMA, FEA and TMPD compared to those for Co(Phen)3+(3) and Fe(CN)3-(6). It is suggested that the reaction pocket of the present diaphorase is hydrophobic. The present electrochemical procedure for the determination of the kinetic parameters is applicable widely to similar enzyme reactions.
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PMID:Electron transferase activity of diaphorase (NADH: acceptor oxidoreductase) from Bacillus stearothermophilus. 231 16

An enzymatic assay method for the determination of urinary formic acid is described. Formic acid in urine was cleaved to carbon dioxide and water by formic acid dehydrogenase, whereby NAD+ was converted to NADH, which reacted with INT (p-iodonitrotetrazolium violet) in the presence of NAD-diaphorase. The color thus produced was determined at 500 nm. In addition, a simple gas chromatographic method of urinary formic acid is described, in which head space gas of formic acid methylester was applied into the wide bore column. The urinary formic acid concentrations by the enzymatic method agreed well with that by the gas chromatographic method. A simple gas chromatographic method for urinary methanol assay is also described. Acetonitrile was added to an equal volume of urine containing methanol. After centrifugation, the supernatant was injected into gas chromatography (GC). The peaks of urinary methanol and ethanol were separated by GC. Formic acid and methanol in urine of unexposed healthy subjects and workers exposed to methanol were analyzed by the colorimetric and gas chromatographic methods. Geometric mean concentrations of urinary formic acid and methanol in the healthy subjects were 7.82 mg/g creatinine and 1.34 mg/l, respectively. The concentration ratio of formic acid to methanol in the urine of the workers exposed to methanol was calculated to be 3.67 +/- 2.10, which agreed with the ratio under a controlled exposure experiment. A slower excretion of formic acid than that of methanol in the urine of a volunteer was also observed.
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PMID:Enzymatic assay of formic acid and gas chromatography of methanol for urinary biological monitoring of exposure to methanol. 234 46

Five different procedures are presented for the enzymatic assay of the sum of NAD+ and NADH concentrations. They are based on the principle of amplification by cycling. The reactions involve oxidation of the formate ion, ethanol, glucose, or carnitine catalyzed by the corresponding dehydrogenases. The detection reactions are based on the 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride (INT)/INT-formazan and ferricyanide/ferrocyanide couples and use a diaphorase. Two of the systems presented--with formate ion and ethanol--were coupled with spectrophotometric detection. The absorbance measurement values were multiplied by 3 in the first case and by 20 in the second, with respect to the values that would have been obtained in the same conditions without the amplification system. The accessible concentration ranges were between 0.05 and 100 microM approximately. Three systems--with formate ion, carnitine, and glucose--used an electrochemical detection based on oxidation of the ferrocyanide ion. The response times were of the order of 10 min and the precision of about 5%. The first brought to light some difficulties concerning the design of such devices. For the second, the proportionality constant had a value of the order of 0.25 microA.microM-1 and an accessible concentration range between 0.2 and 40 microM. The third allowed more precise assays for lower concentration values: between 0.02 and 1.5 microM, with a proportionality constant of 0.49 microA.microM-1. Emphasis was placed on the adaptation possibilities of these systems as a function of the assay requirements.
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PMID:Enzymatic amplification for spectrophotometric and electrochemical assays of NAD+ and NADH. 277 86


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