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)

Ovarian cycle in albino rats was applied to ascertain the problem of the relationship between the salivary and endocrine glands, and also of the extent of participation of individual components of the salivary glands with different functional orientation in the endocrine regulation of individual components of the salivary glands. The content of protein, mucopolysaccharides, DNA, and RNA, the activity of NAD- and NADP-diaphorase, alkaline phosphatase, malate and isocitrate dehydrogenase, alpha-leucine-aminopeptidase was studied. Cytospectrophotometric analysis showed that synchronous changes in the activity of the enzymes under study occurred in all the portions of the salivary glands, depending on the ovarian cycle phases. Of the four successive phases of the cycle the greatest activity of the enzymes and of the protein and mucopolysaccharide content was noted during the proestrus and metaestrus. Different metabolic processes were observed in the salivary ducts in comparison with other parts of the gland; this was apparently connected with peculiarities of the secretion and hormone production.
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PMID:[Quantitative histoenzymologic characteristics of the submaxillary salivary glands of white rats during an ovarian cycle]. 14 76

A reduction in the content of neutral mucopolysaccharides in mucous cells of the neck, a slight decrease in the activity of succinate dehydrogenase and NAD-diaphorase in parietal cells, a decrease in the DNA synthesis rate, and an increase in the area of mitochondria and cristae were detected in the gastric mucosa of rats which were in a long-term space flight. In the small intestine, an increase in the activity of glucose-6-phosphate dehydrogenase and leucine aminopeptidase were found. Morphological changes in the liver consisted in infiltrative adiposity. A similar morphological picture was demonstrated in a synchronous experiment on the earth. These changes, however, were nonspecific and reversible (25 days after rehabilitation the picture did not differ from the animal house control).
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PMID:[Morphological changes in the digestive organs during prolonged space flight on the Kosmos-782 biosatellite]. 15

In cells of human embryo skin--muscle tissue transformed by the Rouse sarcoma virus (23rd cell line) and polyoma virus (P-2 cell line), the mitotic activity was 48 0/00 for 23rd line, 51 0/00 for P-2 line as against 28 0/00 in the control cells. The transformed cells possessed greater amounts of RNA and DNA and protein--bound SH-groups, different forms of glycogen deposits, as well as higher acid phosphatase enzyme activities; there was practically no difference in acid mucopolysaccharide content or NAD-H2-diaphorase and succinate dehydrogenase activities.
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PMID:[Morphological and cytochemical characteristics of human cells transformed and made malignant by Rous and polyoma viruses]. 16 14

The effect of 4'-demethyl-epipodophyllotoxin-beta-D-thenylidene glucoside (VM-26) , a semi-synthetic derivative of podophyllotoxin, on the cell cycle was studied with chick embryo fibroblasts cultivated in vitro. DNA, RNA and protein content, as well as NADH-diaphorase activity were determined by quantitative microdensitometry and cytofluorometry. The incorporation of [3H]thymidine and [3H]leucine into DNA and proteins were analysed by autoradiography. These metabolic data correlated with morphological observation showed that VM-26 blocks the cell cycle at different moments of its kinetics depending on both the dose and the time exposure. NADH-diaphorase activity is the first to be affected, then biochemical changes (involving the metabolism of RNA and proteins) and morphological alterations (especially of mitochondria) follow. This suggests that VM-26 may act primarily upon the mechanism of respiration of the cell.
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PMID:A quantitative microdensitometric and autoradiographic study of the effect of 4'-demethyl-epipodophyllotoxin-beta-D-thenylidene glucoside (VM-26) on the cell cycle of cultured fibroblasts. 53 43

In the cells of RH, SPEV and HEp-2 lines irradiated with 6.5 mm radiowaves of 1 mW/cm2 flux density the following phenomena were established: activation of succinate dehydrogenase and ATPase; reduction of cytochrome oxidase, NAD- and NADP-diaphorase, acid and alkaline phosphatase activities; repression of 3H-thymidine incorporation in DNA and of 3H-uridine incorporation in RNA; violation of ultrastructure; suppression of cellular proliferation; decrease of mitotic activity; occurrence of pathological forms of mitosis.
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PMID:[Biological oxidation in cells exposed to microwaves in the millimeter range]. 68 31

Effect of Di(2-ethylhexyl) phthalate (DEHP), was investigated on chemical constituents and activity of certain enzymes of rat liver. A significant increase in liver weight; total and relative to body weight; decrease in total, free and esterified cholesterol; and no change in dry weight, moisture; RNA, DNA, total lipids, phospholipids, pyruvic acid and lactic acid contents was observed in liver of DEHP-treated rats as compared to controls. Activity of 3 mitochondrial enzymes, malic dehydrogenase, cytochrome-c-oxidase and diaphorase were significantly decreased while that of NADH-cytochrome c reductase, RNAase and DNAase remained unaltered upon treatment. The results suggest that DEHP exerts its hepatotoxic effects by interfering with bioenergetics of the cell.
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PMID:Effect of Di-(2-ethylhexyl) phthalate (DEHP) on chemical constituents and enzymatic activity of rat liver. 73 83

The development of cytosolic DT-diaphorase--NAD(P)H dehydrogenase, quinone, EC 1.6.99.2--and its induction by benzo(a)pyrene has been studied in rat liver. DT-diaphorase belongs to the late suckling cluster, because the largest increase in activity can be observed 18 days after birth. A considerable activity is present, however, in the neonatal period. The activity of the enzyme can be prematurely induced by benzo(a)pyrene. A lag phase of 10 h can be observed before the activity of DT-diaphorase starts to increase. This increase in activity proved to be sensitive to inhibitors of mixed-function oxydase and RNA and DNA synthesis.
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PMID:The development of DT-diaphorase in rat liver and its induction by benzo(a)pyrene. 73 48

The alkylating activity of reduced diaziquone was studied by the nitrobenzylpyridine (NBP) assay and was compared to those of the parent compound and aziridine-containing N,N',N"-triethylenethiophosphoramide (Thio-TEPA). Diaziquone (AZQ) was reduced enzymatically by 2e- using S9 cell fraction from MCF-7 cells which is rich in NAA(P)H:quinone-acceptor oxidoreductase (DT-diaphorase) (QAO) activity. One electron enzymatic reduction was performed with NADPH-cytochrome c reductase. The alkylating activity of AZQ increased 3-fold when reduced by 2e-. This increase was inhibited by dicumarol, an inhibitor of QAO. In contrast, the alkylating activity of AZQ did not increase beyond that of the parent compound when reduced by 1e- using purified NADPH-cytochrome c reductase. Similar results were obtained when AZQ was reduced chemically with borohydride (2e-) and with NADPH (1e-). Anaerobic incubations of AZQ with the S9 fraction of MCF-7 cells (2e- reduction) resulted in an increase in NBP alkylation over its aerobic counterpart (1.8-fold) while maintaining the near 3-fold increase in alkylation over untreated AZQ. In contrast, AZQ incubations with NADPH-cytochrome c reductase (1e- reduction) under the same conditions did not result in an NBP alkylation increase over untreated AZQ. These results indicate that AZQ hydroquinone is most likely the responsible species for the observed alkylation of this antitumor agent to DNA and other nucleophiles. The results also suggest that NAD(P)H:quinone-acceptor oxidoreductase is a very important enzyme in the bioactivation of AZQ.
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PMID:Reductive metabolism of diaziquone (AZQ) in the S9 fraction of MCF-7 cells. II. Enhancement of the alkylating activity of AZQ by NAD(P)H: quinone-acceptor oxidoreductase (DT-diaphorase). 130 Oct 71

DT-diaphorase (DTD) mediated reduction of a series of 2,5-bis-substituted-3,6-diaziridinyl-1,4-benzoquinones was found to increase the level of DNA interstrand cross-linking (ISC) formed at neutral pH with an enhancement observed as the pH was decreased to 5.8. The analogues used were symmetrically alkyl-substituted carbamoyl ester analogues of AZQ (D1-D7), 3,6-diaziridinyl-1,4-benzoquinone (DZQ), the 2,5-dimethyl derivative (MeDZQ), and a 2,5-bis[(2-hydroxyethyl)amino] analogue (BZQ). At pH 5.8, the level of DNA ISC induced by enzymatic reduction was as follows: DZQ greater than MeDZQ much greater than D1 (methyl) greater than D3 (n-propyl) greater than D2 (AZQ; ethyl) greater than D5 (n-butyl) greater than D7 (sec-butyl) greater than D4 (isopropyl) D6 greater than (isobutyl). A similar trend was observed at pH 7.2. The level of DNA ISC induced by BZQ, which is not a substrate for DTD, was not increased by enzymatic reduction. Dicumarol, a known inhibitor of DTD, was capable of inhibiting the DNA ISC induced by these quinones upon enzymatic reduction. MeDZQ and DZQ reacted with guanines, as measured by Maxam and Gilbert sequencing, with a sequence selectivity similar to that of the nitrogen mustard class of antitumor agents. Enzymatic reduction of DZQ and MeDZQ by DTD was found to alter their sequence-selective alkylation. Reduced DZQ showed enhanced guanine alkylation in 5'-GC-3' sequences and new sites of adenine alkylation in 5'-(A/T)AA-3' sequences. Reduced MeDZQ only showed new sites of adenine alkylation at 5'-(A/T)AA-3' sequences but no enhancement of guanine alkylation. The new sites of adenine alkylation were found to be inhibited in the presence of magnesium and rapidly converted into apurinic sites.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alteration in DNA cross-linking and sequence selectivity of a series of aziridinylbenzoquinones after enzymatic reduction by DT-diaphorase. 137 18

The role of the two-electron reducing enzyme DT-diaphorase in the activation of mitomycin C under hypoxic conditions was investigated. Mitomycin C activity was compared in L5178Y murine lymphoblasts, which have low levels of DT-diaphorase activity, and L5178Y/HBM10 cells, which have elevated levels of enzyme activity. The cytotoxic and DNA cross-linking activities of mitomycin C were greater in L5178Y/HBM10 cells than in L5178Y cells. In L5178Y/HBM10 cells, dicoumarol, an inhibitor of DT-diaphorase, decreased cell kill and DNA cross-linking by mitomycin C in air but had no significant effect on these activities under hypoxia. By comparison, in L5178Y cells, dicoumarol had no effect on drug activity under either aerobic or hypoxic conditions. A model for the activation of mitomycin C by both one-electron and two-electron reduction is proposed. Our findings suggest that two-electron reduction by DT-diaphorase has only a limited role in the activation of mitomycin C under hypoxic conditions, although this enzyme appears to be an important contributor to drug activation under aerobic conditions.
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PMID:Role of NAD(P)H:(quinone acceptor) oxidoreductase (DT-diaphorase) in activation of mitomycin C under hypoxia. 137 99


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