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)

Androgen level and the activity of lactate dehydrogenase, succinic dehydrogenase, 17 beta-hydroxysteroid dehydrogenase and NADP-diaphorase was studied in cultured Leydig cells obtained from testes of male mice from inbred strains KP and CBA following a single injection of cadmium chloride. Mice from CBA strain, known to be resistant to the toxic effects of cadmium showed no differences in the enzyme activity and endocrine function of gonads, as compared with control animals. In KP mice, sensitive to cadmium, a marked decrease of activity of all studied dehydrogenases, as well as a fall of androgen level was observed following cadmium administration. The decrease of hormone secretion occurred on the 2nd day of tissue culture and showed a correlation with the 17 beta-hydroxysteroid dehydrogenase activity.
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PMID:Effect of cadmium on androgen level and oxidoreductive enzymes activity in cultured leydig cells of KP and CBA mice. 694 54

Tendon tissue of eleven athletes suffering from insertion tendopathy and of two controls was examined. Part of the tissue was prepared for routine light microscopy, a part for enzyme histochemical staining of Nicotinamide-adenine-dinudeotide-diaphorase (NADP-diaphorase), lactate dehydrogenase (LDH), beta-glucuronidase and alkaline phosphatase. Small pieces of tissue were also prepared for electron microscopic examination. The removed tissue was edematous and mushy. The normally densely packed parallel or interwoven collagen bundles were loosened by edema, focal necrosis or hemorrhage. Infiltration of fatty tissue and granulation tissue was also present. The amount of acid mucopolysaccharides was markedly increased. The histochemical studies showed strong enzyme activity of NADP-diaphorase and LDH in normal tendon tissue as well as around areas of degeneration and in granulation tissue. beta-Glucuronidase and alkaline phosphatase was present, but in general with lesser activity than the above enzymes. The electron microscopic examination revealed marked degeneration of the fiber systems, focal necrosis, deposit of amorphous masses and mucopolysaccharides and focal mineralisation. The reparative zones showed proliferating capillaries, often with a collapsed lumen and prominent endothelial cells and basement membranes.
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PMID:Insertion tendopathy in athletes. A light microscopic, histochemical and electron microscopic examination. 712 23

1-Methoxy-5-methylphenazinium methyl sulfate (1-methoxyPMS) is a photochemically stable electron mediator between NAD(P)H and tetrazolium dyes. We have examined the efficiency of 1-methoxyPMS as an electron mediator in the assay of human lactate dehydrogenase (LDH, EC 1.1.1.27) and the activity staining of LDH isozymes after electrophoresis. The turnover number of 1-methoxyPMS as an electron mediator between NADH and nitrotetrazolium blue was 10--12 s-1, which is a value equal to that of PMS. Correlation coefficient between the estimated LDH activities of human sera obtained with 1-methoxyPMS and those obtained with diaphorase was 0.998. 1-MethoxyPMS successfully substituted for the unstable PMS in the activity staining of LDH isozymes of human serum, giving less background staining. We conclude that 1-methoxyPMS will be useful for routine methods of activity assay and activity staining of enzymes of diagnostic importance.
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PMID:Use of 1-methoxy-5-methylphenazinium methyl sulfate (1-methoxyPMS) in the assay of some enzymes of diagnostic importance. 735 52

Enhanced formation of nitric oxide (NO) by both the constitutive and the inducible isoforms of NO synthase (NOS) has been implicated in the pathophysiology of a variety of diseases, including circulatory shock. Non-isoform-selective inhibition of NO formation, however, may lead to side effects by inhibiting the constitutive isoform of NOS and, thus, the various physiological actions of NO. S-Methylisothiourea sulfate (SMT) is at least 10- to 30-fold more potent as an inhibitor of inducible NOS (iNOS) in immunostimulated cultured macrophages (EC50, 6 microM) and vascular smooth muscle cells (EC50, 2 microM) than NG-methyl-L-arginine (MeArg) or any other NOS inhibitor yet known. The effect of SMT on iNOS activity can be reversed by excess L-arginine in a concentration-dependent manner. SMT (up to 1 mM) does not inhibit the activity of xanthine oxidase, diaphorase, lactate dehydrogenase, monoamine oxidase, catalase, cytochrome P450, or superoxide dismutase. SMT is equipotent with MeArg in inhibiting the endothelial, constitutive isoform of NOS in vitro and causes increases in blood pressure similar to those produced by MeArg in normal rats. SMT, however, dose-dependently reverses (0.01-3 mg/kg) the hypotension and the vascular hyporeactivity to vasoconstrictor agents caused by endotoxin [bacterial lipopolysaccharide (LPS), 10 mg/kg, i.v.] in anesthetized rats. Moreover, therapeutic administration of SMT (5 mg/kg, i.p., given 2 hr after LPS, 10 mg/kg, i.p.) attenuates the rises in plasma alanine and aspartate aminotransferases, bilirubin, and creatinine and also prevents hypocalcaemia when measured 6 hr after administration of LPS. SMT (1 mg/kg, i.p.) improves 24-hr survival of mice treated with a high dose of LPS (60 mg/kg, i.p.). Thus, SMT is a potent and selective inhibitor of iNOS and exerts beneficial effects in rodent models of septic shock. SMT, therefore, may have considerable value in the therapy of circulatory shock of various etiologies and other pathophysiological conditions associated with induction of iNOS.
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PMID:Beneficial effects and improved survival in rodent models of septic shock with S-methylisothiourea sulfate, a potent and selective inhibitor of inducible nitric oxide synthase. 752 23

This study investigated the effect of inducers on the major enzymes responsible for metabolising the quinone antitumor agent mitoxantrone, and on its cytotoxicity in MCF 7 human breast cancer cells. Four inducers were used: 1,2-benzanthracene (BA), phenobarbitone (PB); rifampicin (R) and dexamethasone (DEX). Of these, BA was the most effective, increasing cytochrome P450 dependent metabolism 64-fold and DT-diaphorase activity 1.6-fold. R did not cause an increase in any of the enzyme activities measured and, in fact inhibited glutathione peroxidase activity. PB and DEX increased NADPH cytochrome c reductase activity but had no effect on either DT-diaphorase or cytochrome P450 dependent activities. BA potentiated the cytotoxicity of mitoxantrone in terms of leakage of lactate dehydrogenase (LDH) activity and loss of reduced glutathione (GSH) and protein from cultures. PB had a smaller potentiating effect on cytotoxicity and DEX had no effect. Studies with the enzyme inhibitors, dicoumarol (inhibits DT-diaphorase) and metyrapone (inhibits cytochrome P450), indicate that at least two reactive species are involved in mitoxantrone cytotoxicity. One intermediate, formed by cytochrome P450, caused LDH leakage and GSH depletion. Formation of the second intermediate was catalysed by DT-diaphorase and this hydroquinone caused loss of intracellular protein and GSH. We propose that autooxidation of the hydroquinone resulting in generation of reactive oxygen species contributes to mitoxantrone cytotoxicity. Concomitant exposure to inducing agents may alter the cytotoxicity associated with many cytotoxic drugs, not just mitoxantrone, and this is an important consideration as many cytotoxics have a narrow therapeutic index.
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PMID:The activity of xenobiotic enzymes and the cytotoxicity of mitoxantrone in MCF 7 human breast cancer cells treated with inducing agents. 754 30

This paper describes a detection system for beta-lactams using a commercially prepared carboxypeptidase enzyme (CPase) and a substrate system in which lactic acid is cleaved from a synthetic peptide, N alpha-N epsilon-diacetyl-L-lysyl-d-alanyl-d-lactic acid. The lactate is itself oxidized by lactate dehydrogenase to form NADH. Oxidized NAD+ is regenerated by diaphorase with the simultaneous reduction of the colourless 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride hydrate (INT) indicator substrate to produce a red-mauve colour that is proportional to CPase activity. The presence of beta-lactams decreases the intensity of colour produced. The lower limit of detection for benzyl penicillin (Pen G) by this system is 20 ng g-1 compared with 50 ng g-1 by the same assay but using a R-d-ala-d-ala substrate from a commercial kit.
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PMID:Improved spectrophotometric assay for beta-lactam residues in kidney tissue. 787 84

The detection of recent myocardial damage by means of the macroscopic lactate dehydrogenase reaction (LDHr) linked to nicotinamide adenine dinucleotide diaphorase (NADHd), conducted in a liquid medium is greatly insensitive to postmortal autolysis. In 10 heart cones (i.e., cardiac ventricles severed underneath the coronary sulcus) stored at 6 degrees C for up to 114 h after death, no autolytic artifacts appeared on freshly cut apical surfaces of transverse myocardial slices. In 10 cones kept at room temperature for up to 95 h after death, no artifacts appeared in eight cases; in two cases the LDHr was impaired by postmortal bacterial spread and decomposition of the myocardium. Intravital perfusion of injured myocardium increases the sensitivity of the LDHr. Postmortal stand-still of circulation is decisive in preserving dehydrogenase activities in undamaged myocardium. An artificial decrease in enzyme activity always appeared on the nonrecent, basally facing cut surfaces of slices exposed to air and fluid oozing out of the myocardium for long periods, even if the exposed surface of the cone was kept at 6 degrees C and wrapped in plastic. In normal practice, when bodies are stored in a refrigerating unit, the LDHr may still indicate myocardial damage more than 114 h after death.
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PMID:The usefulness of the lactate dehydrogenase macroreaction in autopsy practice. 830 18

The elevation of intracellular Ca2+ in various tissue through oxidative stress induced by menadione has been well documented. Increase of Ca2+ level in platelets results in aggregation of platelets. To test the hypothesis that menadione-induced Ca2+ elevations can play a role in platelet aggregation, we have studied the effect of menadione on aggregation of platelets isolated from female rats. Treatment with menadione to platelet-rich plasma (PRP), which proved to be an adequate system, appeared to induce dose-dependent platelet aggregations up to 60%, as determined by aggregometry. However, exposure of PRP to menadione led to slow reduction of platelet cell number coincident with a loss of viability, as measured by lactate dehydrogenase leakage, suggesting that menadione might induce cell lysis rather than aggregation of platelets. Light microscopy confirmed that menadione reduced the number of platelets and failed to show aggregates of platelets. To elucidate the mechanism of this cytotoxicity, menadione-induced oxygen consumption was studied in intact rat platelets. Incubation of platelets with menadione resulted in rapid dose-dependent increases of oxygen consumption, which were not inhibited by indomethacin and nordihydroguaiaretic acid, suggesting that menadione did not affect the cyclooxygenase and lipoxygenase pathways in platelets. Oxygen consumption, as well as cytotoxicity by menadione, was unaffected by addition of dicoumarol, which is a quinone reductase (QR) inhibitor. Consistent with these findings, no activity of QR was detected in any subcellular fractions of platelets. Oxygen consumption by several subcellular platelet fractions treated with menadione was examined in the presence of NADPH or NADH. Additions of NADPH or NADH to microsomal fractions or a 9000 g pellet (which contains plasma membranes) led to 2-fold to 18-fold elevations in platelets may contribute to the oxidative damage associated with menadione-induced oxygen consumption, respectively. These results suggest that NADPH and/or NADH-dependent enzyme systems in menadione-induced cytotoxicity.
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PMID:Mechanism of menadione-induced cytotoxicity in rat platelets. 865

Superoxide dismutase-like activity (SOD-like), isoenzyme lactate dehydrogenase-C4 (LDH-C4) and NADH-diaphorase activities in spermatozoa have been investigated from 58 normozoospermic and 27 oligozoospermic men. Significantly higher SOD-like, LDH-C4 and diaphorase activities (P < 0.01, P < 0.005 and P < 0.0001, respectively) were detected in spermatozoa from oligozoospermic men, compared to the activities found in normozoospermic samples. SOD-like activity (mean +/- SE) in oligozoospermic samples amounted to 8.3 +/- 1.6 U 10(-8) spermatozoa, while in spermatozoa in normozoospermic men with a sperm concentration above 20 million of spermatozoa per ml amounted to 4.2 +/- 0.5 U 10(-8). There was a close correlation between the SOD-like activity and biochemical indicators of the presence of residual cytoplasm i.e. isoenzyme LDH-C4 and NADH-diaphorase (r = 0.53 and r = 0.66 in normozoospermic and r = 0.63 and r = 0.54 in oligozoospermic men, respectively). A positive relationship between SOD-like activity and experimentally-induced lipid peroxidation was detected in 54 infertile men (r = 0.30; P < 0.05). These findings suggest that a higher level of superoxide dismutase-like activity may reflect a defect in the development or maturation of spermatozoa and, thereby, a decreased fertility potential. Hence, determination of SOD-like activity may give information on the state of maturity of human spermatozoa, while its role in the antioxidative protection remains to be determined.
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PMID:Relationship of sperm superoxide dismutase-like activity with other sperm-specific enzymes and experimentally induced lipid peroxidation in infertile men. 884 16

The localisation of diaphorase was visualised by light microscopy using the dye nitro blue tetrazolium and NADPH as substrates. Under appropriate conditions, diaphorase reduces this dye to a dark blue insoluble formazan. The enzyme was located at very low activity in many tissue and glandular structures of the deer, but at very much higher activity in sebaceous glands in the dermal velvet of the antler and skin, and in additional sebaceous gland-related structures in the ear canal, prepuce and tail (scent) gland. Within sebaceous glands, activity was greatest in the outermost layers of the acini, but decreased as the cells progressed and differentiated centripetally. There was little or no difference between the staining observed when NADH was used as a substrate, compared to NADPH. There was generalised staining (usually light) for glucose-6-phosphate dehydrogenase, lactate dehydrogenase, and glycerol-3-phosphate dehydrogenase. However, this staining was not specifically localised to sebaceous glands and related structures, showing that the observed activity in these structures was due to a diaphorase that was distinct from any of the dehydrogenase activities tested. The possible role of diaphorase in sebaceous development and secretion is discussed.
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PMID:Diaphorase activity in sebaceous glands and related structures of the male red deer. 1042 9


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