Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Study of the activity of some myocardial enzymes in sudden death cases with alcoholic cardiomyopathy (ACMP) was made by quantitative histochemical methods. The decrease of dehydrogenase activity of succinate, lactate, beta-hydroxybutyrate, alpha-glycerophosphate and NAD-diaphorase was found in line with the increase of the activity of glucose-6-phosphate dehydrogenase, alcohol dehydrogenase and catalase versus control (myocardium of those who died of trauma). Disorders of major metabolic processes in the myocardium may occasionally lead to electrical instability resulting in ventricular fibrillation and sudden cardiac death. In almost 80% of sudden cardiac deaths in ACMP foci of acute myocardial ischemia are found, that can lead to ventricular fibrillation with lethal outcome.
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PMID:[Histoenzymologic characteristics of the myocardium in sudden death in patients with alcoholic cardiomyopathy]. 380 Jun 78

Results of histochemical study of testicular tissue in 31 patients, aged 2.5 to 31 years, suffering from dysgenesia syndrome of the testis are presented. Enzymes and lipids furnishing synthesis of steroid hormones (3-beta-oxysteroid dehydrogenase, alcohol dehydrogenase, glucose-6-phosphate dehydrogenase. NAD- and NADP-diaphorase, cholesterol and its esters) were revealed in Leydig's cells of pubertal-juvenile and adult patients, in Leydig's cells precursors in children, and also in Sertoli's cells of all these patients. All these cellular elements possessed high activity of the enzymes under study. It is suggested that Sertoli cells and Leydig's cells precursors, along with mature Leydig's cells, provide a sufficiently high functional activity of the gonads in patients with dysgenesia of the testis.
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PMID:[Functional activity of gonadal glandular cells in patients with testicular dysgenesis]. 699 Apr 2

A kinetic study is made of a system consisting of a specific enzymic cycling assay coupled to an enzymic reaction. A kinetic analysis of this system is presented, and the accumulation of chromophore involved in the cycle is seen to be parabolic, i.e. the rate of the reaction increases continuously with constant acceleration. The system is illustrated by the measurement of alkaline phosphatase activity using beta-NADP+ as substrate. The enzymes alcohol dehydrogenase and diaphorase are used to cycle beta-NAD+ in the presence of ethanol and p-Iodonitrotetrazolium Violet. During each turn of the cycle, one molecule of the tetrazolium salt is reduced to an intensely coloured formazan. A simple procedure for evaluating the kinetic parameters involved in the system and for optimizing this cycling assay is described. The method is applicable to the measurement of any enzyme, and its amplification capacity as well as the simplicity of determining kinetic parameters enable it to be employed in enzyme immunoassays to increase the magnitude of the measured response.
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PMID:Kinetic study of an enzymic cycling system coupled to an enzymic step: determination of alkaline phosphatase activity. 761 54

IgG antibodies against the 2,3-di-o-acyltrehalose glycolipid of Mycobacterium tuberculosis were determined in a set of 49 sera from patients with pulmonary tuberculosis and 65 negative control subjects. We compared a conventional ELISA method using a beta-galactosidase anti-human IgG conjugate developed with ONPG, with an amplification ELISA system constituted of an anti-human IgG biotinylated conjugate, a streptavidin-alkaline phosphatase complex, and NADP as a substrate. The resulting NAD was measured by using a redox enzymatic recycling system of alcohol dehydrogenase, diaphorase and iodonitrotetrazolium as chromogen. With specificity set at 92.31% in both methods, we obtained a sensitivity of 42.86% in the conventional method and a sensitivity of 61.22% in the amplified method. We conclude that by using a more sensitive method we can detect cases that otherwise could be identified as false negatives.
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PMID:Development of an enzyme-linked immunosorbent assay (ELISA) combined with a streptavidin-biotin and enzyme amplification method to detect anti-2,3-di-o-acyltrehalose (DAT) antibodies in patients with tuberculosis. 782 39

The mechanism of reduction of p-nitrosophenol (pNSP) catalyzed by horse liver alcohol dehydrogenase (HADH) and human pi-alcohol dehydrogenase (pi-ADH) has been compared in transient and steady-state experiments. Our results indicate that pNSP reduction catalyzed by these two ADH proceeds by different mechanisms. In one mechanism, shown by Equation 1, pNSP is reduced to p-aminophenol (pAP) via two enzymatic steps (Steps 1 and 3), which are mediated by the nonenzymatic dehydration of p-N-hydroxyaminophenol (pN-OHAP) to 1,4-benzoquinoneimine (BQI) (Step 2). [formula: see text] Pathway (I) is proposed mainly for pi-ADH but can be catalyzed by HADH. However, Step 3 is catalyzed approximately 2 orders of magnitude more slowly by HADH than by pi-ADH. This conclusion is confirmed by the results, which indicate that pi-ADH very efficiently catalyzes the reduction of BQI and 1,4-benzoquinone (BQ) to the corresponding hydroquinones. The kinetic constants determined at pH 7.4 suggest that pi-ADH is a more efficient quinone reductase and nitroso reductase than it is an ethanol oxidase or acetaldehyde reductase. An alternative mechanism of pNSP reduction, shown by Equation 2, is suggested for HADH. In this mechanism, formation of the p-hydroxybenzylnitrenium ion (pNH+P) occurs at the active-site zinc ion of the enzyme (Step 2) and accelerates further nonenzymatic reduction to pAP or hydrolysis to BQ (Step 3). [formula: see text]
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PMID:Mechanism of p-nitrosophenol reduction catalyzed by horse liver and human pi-alcohol dehydrogenase (ADH). Human pi-ADH as a quinone reductase. 798 27

The ethanol determination using the ADH/REA method (Abbott TDx-REA) is based on the principle of radiative energy attenuation (REA) applying the classic ADH-method. However, instead of measuring the extinction of the reaction product NADH, a chromogen formed by a coupled diaphorase reaction is measured. Serum, whole blood and urine are used for ethanol determination without prior treatment. The following analytical procedures such as sampling, addition of reagents and measuring are automated. Sample solutions of 100 to 200 microliters should be used. Daily calibration of the apparatus is recommended. Both precision and reproducibility meet the requirements of BAC-assays in forensic specimens. The results obtained by using gas chromatography and ADH/REA method show an excellent correlation (factor r = 0.9977). The ADH/REA method has proved to be a reliable assay procedure in routine determination of the BAC in forensic samples.
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PMID:[Use of the ADH/REA method (Abbott Tdx-REA) in forensic blood alcohol determination]. 867 35

A range of potential chemoprotective agents, most of them natural dietary constituents, has been examined for ability to modulate both phase I (cytochrome P450 1A1, 1A2, 2B1/2, 2C11, 2E1, 3A, 4A) and phase II drug metabolizing enzymes (glutathione S-transferases, in particular subunits Yc2 and P, aflatoxin B1-aldehyde reductase and quinone reductase) in rat liver. In addition to assays of total enzyme activity and Western blots for individual isozymes, the ability of microsomes to metabolize aflatoxin B1, and of cytosols to conjugate aflatoxin B1 (AFB1)-epoxide to GSH and to produce AFB1-dialcohol, were measured. Induction of gamma-glutamyl transpeptidase activity was examined by histochemistry. Differing patterns of induction were observed, reflecting differences in the control of expression of the individual enzymes studied. Of the compounds examined, butylated hydroxytoluene, ethoxyquin, indole-3-carbinol and phenethyl isothiocyanate were the most potent bifunctional agents (inducing both phase I and II activities). Oltipraz, while only weakly inducing CYP1A2 and 2B1/2, was a potent inducer of phase II enzymes. Caffeic acid, garlic oil, sinigrin and propyl gallate all showed some ability to induce phase II enzymes. 4-Methyl catechol, alpha-tocopherol and red wine decreased certain phase I enzyme activities, while inducing total GST activity. Butylated hydroxytoluene, ethoxyquin, garlic oil and indole-3-carbinol induced gamma glutamyltranspeptidase in periportal hepatocytes. Particularly because of their ability to induce the detoxifying activities of glutathione S-transferase Yc2 and aldehyde reductase, butylated hydroxytoluene, ethoxyquin, indole-3-carbinol, oltipraz, phenethyl isothiocyanate and sinigrin will be effective blocking agents in rodents, if administered prior to AFB1. While these studies indicate the relative contributions of phase I and II metabolism in the overall protective effect in rat, care should be taken that a similar balance is achieved in man, and that relevant enzymes or iso forms are induced.
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PMID:Mechanism of action of dietary chemoprotective agents in rat liver: induction of phase I and II drug metabolizing enzymes and aflatoxin B1 metabolism. 932 68

Structurally diverse compounds can confer resistance to aflatoxin B1 (AFB1) hepatocarcinogenesis in the rat. Treatment with either phytochemicals [benzyl isothiocyanate, coumarin (CMRN), or indole-3-carbinol] or synthetic antioxidants and other drugs (butylated hydroxyanisole, diethyl maleate, ethoxyquin, beta-naphthoflavone, oltipraz, phenobarbital, or trans-stilbene oxide) has been found to increase hepatic aldo-keto reductase activity toward AFB1-dialdehyde and glutathione S-transferase (GST) activity toward AFB1-8,9-epoxide in both male and female rats. Under the conditions used, the natural benzopyrone CMRN was a major inducer of the AFB1 aldehyde reductase (AFAR) and the aflatoxin-conjugating class-alpha GST A5 subunit in rat liver, causing elevations of between 25- and 35-fold in hepatic levels of these proteins. Induction was not limited to AFAR and GSTA5: treatment with CMRN caused similar increases in the amount of the class-pi GST P1 subunit and NAD(P)H: quinone oxidoreductase in rat liver. Immunohistochemistry demonstrated that the overexpression of AFAR, GSTA5, GSTP1, and NAD(P)H:quinone oxidoreductase affected by CMRN is restricted to the centrilobular (periacinar) zone of the lobule, sometimes extending almost as far as the portal tract. This pattern of induction was also observed with ethoxyquin, oltipraz, and trans-stilbene oxide. By contrast, induction of these proteins by beta-naphthoflavone and diethyl maleate was predominantly periportal. Northern blotting showed that induction of these phase II drug-metabolizing enzymes by CMRN was accompanied by similar increases in the levels of their mRNAs. To assess the biological significance of enzyme induction by dietary CMRN, two intervention studies were performed in which the ability of the benzopyrone to inhibit either AFB1-initiated preneoplastic nodules (at 13 weeks) or AFB1-initiated liver tumors (at 50 weeks) was investigated. Animals pretreated with CMRN for 2 weeks prior to administration of AFB1, and with continued treatment during exposure to the carcinogen for a further 11 weeks, were protected completely from development of hepatic preneoplastic lesions by 13 weeks. In the longer-term dietary intervention, treatment with CMRN before and during exposure to AFB1 for a total of 24 weeks was found to significantly inhibit the number and size of tumors that subsequently developed by 50 weeks. These data suggest that consumption of a CMRN-containing diet provides substantial protection against the initiation of AFB1 hepatocarcinogenesis in the rat.
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PMID:Chemoprevention of aflatoxin B1 hepatocarcinogenesis by coumarin, a natural benzopyrone that is a potent inducer of aflatoxin B1-aldehyde reductase, the glutathione S-transferase A5 and P1 subunits, and NAD(P)H:quinone oxidoreductase in rat liver. 1070 11

The major metabolic pathways involved in synthesis and disposition of carbonyl and hydroxyl group containing compounds are presented, and structural and functional characteristics of the enzyme families involved are discussed. Alcohol and aldehyde dehydrogenases (ADH, ALDH) participate in oxidative pathways, whereas reductive routes are accomplished by members of the aldo-keto reductase (AKR), short-chain dehydrogenases/reductases (SDR) and quinone reductase (QR) superfamilies. A wealth of biochemical, genetic and structural data now establishes these families to constitute important phase I enzymes.
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PMID:Molecular and structural aspects of xenobiotic carbonyl metabolizing enzymes. Role of reductases and dehydrogenases in xenobiotic phase I reactions. 1078 73

cADP-ribose (cADPR) is a novel cyclic nucleotide derived from NAD(+) that has now been established as a general Ca(2+) messenger in a wide variety of cells. Despite the obvious importance of monitoring its cellular levels under various physiological conditions, its measurement has been technically difficult and requires specialized reagents. In this study a widely applicable high-sensitivity assay for cADPR is described. ADP-ribosyl cyclase normally catalyses the synthesis of cADPR from NAD(+), but the reaction can be reversed in the presence of high concentrations of nicotinamide, producing NAD(+) from cADPR stoichiometrically. The resultant NAD(+) can then be coupled to a cycling assay involving alcohol dehydrogenase and diaphorase. Each time NAD(+) cycles through these coupled reactions, a molecule of highly fluorescent resorufin is generated. The reaction can be conducted for hours, resulting in more than a thousand-fold amplification of cADPR. Concentrations of cADPR in the nanomolar range can be measured routinely. The unique ability of ADP-ribosyl cyclase to catalyse the reverse reaction provides the required specificity. Using this assay, it is demonstrated that cADPR is present in all tissues tested and that the levels measured are directly comparable with those obtained using a radioimmunoassay. All the necessary reagents are widely available and the assay can be performed using a multiwell fluorescence plate reader, providing a high-throughput method for monitoring cADPR levels. This assay should be valuable in elucidating the messenger role of cADPR in cells.
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PMID:A novel cycling assay for cellular cADP-ribose with nanomolar sensitivity. 1177 10


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