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 cerebral thrombosis of the rat with 35 micrometer labeled microspheres gives infarcted areas easily seen. After 15 min, in these areas, there is no change in NADH diaphorase-, succinic-dehydrogenase-, mono-amino-oxidase-, glucose-6-phosphate-dehydrogenase-, isocitric dehydrogenase-, lactic-dehydrogenase-, ATPase, alpha galactosidase-, acid phospatase activity. After 2, 4, 6 h all these activities diminish in the neuropil but they are preserved in the neurones for diaphorase, succinic-dehydrogenase and mono-amino-oxidase. The margin of infarcted areas shows a strong staining for acid phosphatase. Before 2 h there is not enzymatic changes neither oedema. This experimental model seems trustly and could be developped.
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PMID:[Brain rat histoenzymological changes induced by microsphere injection during ischemia (author's transl)]. 11 18

NADH and NADPH diaphorase isozymes have been studied in human tissues. Evidence from rare heterozygotes suggests that the red cell and main tissue forms of NADH diaphorase are products of the same locus DIA1. NADPH-dependent diaphorase appears to be the product of a second locus DIA2. A third locus, DIA3, codes for the polymorphic sperm diaphorase. The products of this locus are also found in foetal tissues including placenta and adult brain and gonads. The products of these three loci may be distinguished by their substrate specificity, thermostability and molecular size.
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PMID:An interpretation of human diaphorase isozymes in terms of three gene loci DIA1, DIA2 and DIA3. 56 99

The chemoarchitecture of the pretectal complex of the rabbit was examined in sections stained by acetylcholinesterase (AChE) and reduced nicotinamide adenine dinucleotide (NADH) diaphorase in the coronal, horizontal and sagittal plane. Twelve different subdivisions can be identified in the rabbit pretectum on the basis of the distribution of both histochemical markers. According to the standard terminology, the pretectal complex of the rabbit consists of: the nucleus of the optic tract; the anterior, posterior, olivary and medial pretectal nuclei; the nucleus of the posterior commissure; the periventricular subcommissural gray; the suprageniculate and internal suprageniculate nuclei, and the dorsal, lateral and medial terminal nuclei of the accessory optic system. The combined use of several sectioning planes and the histochemical mapping of AChE and NADH diaphorase have been of value in resolving the structural limits within transitional regions of the pretectum.
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PMID:The pretectal complex of the rabbit: distribution of acetylcholinesterase and reduced nicotinamide adenine dinucleotide diaphorase activities. 151 63

1. After immunization of BALB/c mouse, four monoclonal antibodies against soluble NADH diaphorase from ejaculated boar spermatozoa were produced and characterized. The monoclonal antibodies were designated as follows Mab 1F2, Mab 4E2, Mab 5B8, Mab 5D8. 2. These monoclonal antibodies react with other enzyme forms-sedimentary NADH and NADPH and soluble NADPH and inhibit (although not completely) their activity. It is supposed that different forms of the enzyme share some common epitopes. 3. Treatment of ejaculated boar semen with 2O-methylcholanthrene causes an increase of the activity of the soluble diaphorase form only. 4. These results lead to the assumption that the sperm diaphorase is a dynamic enzyme system consisting of four immunologically similar isoenzymes although their functions are different.
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PMID:Characterization of NAD(P)H diaphorase from boar spermatozoa using specific monoclonal antibodies. 170 1

The distribution of acetylcholinesterase and reduced nicotinamide adenine dinucleotide (NADH) diaphorase enzymatic activities was mapped histochemically in the dorsal thalamus of the rabbit. A comparison of the resulting patterns helped in the histochemical delimitation of a number of nuclei, as well as in the detection of some subdivisions, that showed differential expression of these enzymes. It was observed that AChE and NADH diaphorase tend to appear in a complementary fashion in many dorsal thalamic neuropiles, so that intense activity of the one was accompanied by low activity of the other. However, coincident expression of both enzymes was also obtained in a small number of areas. The correlation of these patterns with other chemo-architectonic and hodologic data does not yet disclose an explanation of these regularities, which however suggest some functional significance.
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PMID:Comparative mapping of acetylcholinesterase and reduced nicotinamide adenine dinucleotide diaphorase in the rabbit dorsal thalamus. 186 63

Topical application on rat oral mucosa of the chemical 4-nitroquinoline 1-oxide (4NQO) has been shown to produce squamous cell carcinomas on the posterior tongue and/or the posterior hard palate. 4NQO is broken down in vivo by a diaphorase, 4NQO reductase (E.C.1.6.99.2), to produce an active molecule believed to be responsible for carcinogenesis. It has been shown that there are higher concentrations of 4NQO reductase in oesophageal mucosa compared with elsewhere in the gastrointestinal tract. The purpose of these experiments was to compare the distribution of certain diaphorases in the oral mucosa. Samples of rat tongue and cheek epithelia were homogenized, then ultracentrifuged to provide mixed cytosol and microsome fractions from the epithelial cells. A spectrophotometer was used to measure the variation in absorbance at 340 nm of NADH consumed by reduction of 4NQO by enzymes present in the tissue extracts. A histochemical technique was used to compare the activity of NADH diaphorase, NADP diaphorase and glucose-6-phosphate dehydrogenase at different sites of the oral mucosa. Statistical analysis showed that there were significant (P less than 0.01) differences between the activities of all three enzymes at different sites of the oral mucosa. In each case, a higher activity was found at the sites of high incidence of squamous cell carcinoma. A lower activity was found at sites where carcinomas did not occur.
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PMID:A relationship found between intra-oral sites of 4NQO reductase activity and chemical carcinogenesis. 211 96

Considerable evidence suggests that the release of iron from ferritin is a reductive process. A role in this process has been proposed for two hepatic enzymes, namely xanthine oxidoreductase and an NADH oxidoreductase. The abilities of xanthine and NADH to serve as a source of reducing power for the enzyme-mediated release of ferritin iron (ferrireductase activity) were compared with turkey liver and rat liver homogenates. The maximal velocity (Vmax.) for the reaction with NADH was 50 times greater than with xanthine; however, the substrate concentration required to achieve half-maximal velocity (Km) was 1000 times less with xanthine than with NADH. NADPH could be substituted for NADH with little loss in activity. Dicoumarol did not inhibit the reaction with NADH or NADPH, demonstrating that the ferrireductase activity with those substrates was not the result of the liver enzyme 'DT-diaphorase' [NAD(P)H dehydrogenase (quinone)]. A flavin nucleotide was required for ferrireductase activity with rat and turkey liver cytosol when xanthine, NADH or NADPH was used as the reducing substrate. FMN yielded twice the activity with NADH or NADPH, whereas FAD was twice as effective with xanthine as substrate. Kinetic comparisons, differences in lability and partial chromatographic resolution of the ferrireductase activities with the two types of reducing substrates strongly indicate that the ferrireductase activities with xanthine and NADH are catalysed by separate enzyme systems contained in liver cytosol. Complete inhibition by allopurinol of the ferrireductase activity endogenous to undialysed liver cytosol preparations and the ability of xanthine to restore equivalent activity to dialysed preparations indicate that the source of reducing power for the endogenous activity is xanthine. These studies suggest that xanthine, NADH or NADPH can serve as a source of reducing power for the enzyme-mediated reduction of ferritin iron, with a flavin nucleotide serving as the shuttle of electrons from the enzymes to the ferritin iron.
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PMID:The mobilization of ferritin iron by liver cytosol. A comparison of xanthine and NADH as reducing substrates. 277 99

Methylthioketobutyric acid has been used as an indicator for the production of reactive oxygen species during incubation with xanthine oxidase or NADH diaphorase in the presence of an autooxidizable quinone. The production of OH-radical-type oxidants is enhanced in the presence of crocidolite but not by the asbestos types chrysotile or amosite. This activity of crocidolite in the diaphorase system is further stimulated by bisulfite. Crocidolite-dependent ethylene formation from methylthioketo-butyric acid is inhibited by both superoxide dismutase and catalase. In the presence of both crocidolite and bisulfite, however, the inhibition by superoxide dismutase is preserved, but the inhibition by catalase is lost. Since in some respect the NADH-diaphorase quinone system may reflect the situation in the activated macrophage, crocidolite activation may represent a biochemical model system describing potential asbestos toxicity.
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PMID:Cooperative stimulation by sulfite and crocidolite asbestos fibres of enzyme catalyzed production of reactive oxygen species. 285 63

Intrinsic NADPH diaphorase activity is a component of the membrane-bound NAD(P)H:O2 oxidoreductase of human neutrophils. NADH-specific diaphorase activity is also present in membrane fractions rich in oxidoreductase activity. Studies were undertaken to determine whether the NADH diaphorase might also be intrinsic to the oxidoreductase. The latter diaphorase was freed from the membrane by detergent extraction and partially purified approximately 80-fold. Its apparent molecular weight following solubilization in deoxycholate and Tween-20 was 204 000 +/- 10 000. The specific activity of the partially purified diaphorase with ferricyanide as electron acceptor was 7.6 X 10(3) mU/mg protein, its pH optimum was 7.0, and its Km for NADH was 13 microM. It is completely devoid of NADPH diaphorase activity, lacks the capacity to reduce molecular oxygen, yet readily reduces ferricyanide, 2,6-dichlorophenolindophenol and ferricytochrome c. Whereas the NADH diaphorase was freed from the particulate fraction of cell lysates by extraction in 10 mM Tris-HCl buffer (pH 8.6) made up in 15% glycerol and 0.5% Tween-20, NADPH-dependent diaphorase and superoxide-generating activities also present in the membrane were not. These observations make it unlikely that the principal membrane-bound NADH diaphorase found in human neutrophils is a component of the NAD(P)H:O2 oxidoreductase, despite its common association in the same particulate fraction of cell lysates.
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PMID:Purification and resolution of NADH diaphorase activity from NADPH diaphorase-linked: O2 oxidoreductase activity of human neutrophils. 384 37

Evidence that the bactericidal ability and the stimulated oxidative metabolism of leukocytes appear in parallel during fetal development of the Minnesota Miniature pig has been obtained by application of the techniques applied to studies of human cells. It was demonstrated that leukocytes from 87- to 90-day fetuses were fully capable of ingesting Staphylococcus aureus but greatly diminished in bactericidal capacity as compared to leukocytes of older fetuses and adults. Although resting levels of oxygen consumption and hexose monophosphate pathway activity of leukocytes from the younger fetuses compared well with those of leukocytes from older animals, the phagocytosis-stimulated increments of metabolism were much less at 87 to 90 days of gestation than at later developmental stages. Both bactericidal capacity and increased metabolism of leukocytes reach adult levels by 100 days of gestation (normal gestation period of 115 to 120 days). Acrylamide gels stained for reduced nicotinamide adenine dinucleotide (NADH) and NADH phosphate (NADPH) diaphorase activity after disc electrophoresis of leukocyte extracts revealed normal mobility and intensity of NADH diaphorase bands. Three NADPH diaphorase bands were present in adult leukocyte extracts. Only the fast-migrating NADPH diaphorase band of 87- to 90-day cells stained with decreased intensity. This "deficiency" was no longer present at the later fetal period. The fast-migrating NADPH diaphorase band may represent an electron transfer protein which functions in cyanide-insensitive respiration of the leukocytes of the pig.
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PMID:Development of bactericidal capacity and phagocytosis-associated metabolism of fetal pig leukocytes. 463


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