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 arcuate nucleus (AN) and the median eminence (ME) of the hypothalamus were investigated in young and ageing female rats. During the estral cycle (EC) the monoamine (MA) content, the monoaminoxidase (MAO), NADP and NAD-diaphorase activities were determined in the AN, and the MA content and the activity of alkaline phosphatase (AP) -- in the ME. In young rats in the proestrus-estrus there was an increase in the activity of the NADP and NAD-diaphorase and of the MA content, but a decrease of the MAO activity. This indicated an intensified function of the nucleus at these stages of the EC. Accumulation of the MA in the ME was noted in the diestrus, while in the proestrus their concentration sharply fell; on the other hand, the activity of the AP was considerably increased. In the ageing rats the dynamics of the indices under study during the EC were largely unchanged. However, the functional activity of the AN proved to increase, and in the ME and elevation of the MA concentration and disturbance of its release from the nerve terminals was seen.
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PMID:[Concentration of monoamines and activity of several enzymes in the arcuate nucleus of the hypothalamus in young and aging rats during the estrous cycle]. 98 11

Immunization of rabbits with increasing doses of Cl. botulinum toxoid, type B, led to the development in the kidneys of a focal intracapillary productive glomerulonephritis, and also of productive endo- and perivasculites. Blood letting (in the amount of 1% of body weight) aggravated the morphological picture of the affection on account of supervention of the alternative and exudative components. At the same time blood letting led to reduction of the NAD-diaphorase, succinic dehydrogenase and glucose-6-phosphatase activity in the epithelium of the proximal portions of the nephrons.
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PMID:[Histological and histochemical changes in the kidneys of rabbits immunized with Cl. botulinum toxoid type B in combination with blood loss]. 100 41

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

The activities of alkaline phosphatase, NAD diaphorase and NADP diaphorase increased in infantile mouse ovaries in response to injected gonadotrophins. The distribution and activity of these enzymes were studied in detail in the ovaries of normal mice from 1 to 41 days after birth and in mice injected at various ages with FSH, LH and HCG. Granulosa cells contained NAD and NADP diaphorases. Thecal cells contained NADP diaphorase and alkaline phosphatase with NAD diaphorase first appearing in the thecae of larger follicles 11 days after birth. All three enzymes occurred in interstitial tissue, in the interfollicular stroma and in groups of gonadotrophin-responsive cells in the medulla. These medullary cells and the interstitial tissue were stimulated by exogenous LH and HCG but not by FSH. Granulosa, theca and interfollicular tissue were stimulated at some stage by each of the three injected hormones. The normal pattern of development is discussed in relation to the changing serum levels of endogenous gonadotrophin found in similar mice. It is concluded that the enzyme changes were closely and reciprocally related to endogenous hormone concentrations.
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PMID:Histochemical studies on three gonadotrophin-responsive enzymes in the infantile mouse ovary. 112 17

A histichemical study is presented of the activity of some redox enzymes (succinate dehydrogenase, malate dehydrogenase, NAD-diaphorase and lactate dehydrogenase) in 37 cultured human glial brain tumours. The stages of cell activity at different periods of tumour cultivation and the level of their differentiation in the initial tissue were taken into consideration. The examined tumour cultures showed enzymatic cell polymorphizm. During of period of adaptation of explants, the activity of the Krebs cycle enzymes was low to increase during differentiation and proliferation of cultures. The activity of lactate dehydrogenase elevated in tumour cells from cultures of dedifferentiated astrocytomas and glioblastomas mith marked anaplasia. The activity of this enzyme increased also in the course of advanced necrobiotic changes in the tumour cells.
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PMID:[Histochemical study of the enzymatic activity of cultivated human macroglial brain tumors]. 116 47

The activity of 19 enzymes (hexokinase, glucoso-6-phosphatisomerase, alpha-glycerophosphate-, lactate-, succinate-, isocitrate-, malate-, glucoso-6-phosphate-, 6-phosphogluconate-, glutamate-, alcohol-, inosine-5'-phosphate-, guanosine-5'-monophosphate-dehydrogenase, cytochromoxidase NAD.N2- and NADP.N2-diaphorase, monoaminoxidase, alkaline and acid phosphatase) was studied comparatively in the mucosa of control rats and in tumors of the small intestine (27), and large intestine (176), induced in 41 rats percutaneously by 1,2-dimethylhydrazine. A decreased level of the enzymes of tissue respiration and Krebs cycle was found with a simultaneous increase in the activity of the enzymes of glycolysis and pentoso-monophosphate shunt. These data evidence variations in tumor metabolism consisting in oxidizing phosphorylation, being replaced by aerobic glycosis, and also reflecting an intensive proliferation of tumor cells.
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PMID:[An enzymohistochemical study of experimental tumors of the intestine]. 123 60

A study of ingestion and elimination of cells of peritoneal exudate (CPE) of mouse labeled antigens of various physico-chemical nature with a simultaneous analysis of their influence on the function of the enzymatic systems of macrophages showed that both the corpuscular (sheep erythrocytes, typhoid vaccine) and the soluble (albumin, endotoxin of S. typhi, tetanus and staphylococcus toxoid) antigens caused a unitypical reaction of the cells of monocytic phagocytic system. Thirty minutes after the administration the principal mass of labeled antigens (albumin, typhoid vaccine, sheep erythrocytes) was phagocytized by macrophages and was revealed chiefly in their phagolysosomal fraction. The greater part of radioactive material was eliminated in the course of the first 24 hours; however, some of it could be found in the macrophages for a long time. During the process of phagocytosis the activity of lysosomal (catepsin, acid phosphatase, desoxyribonuclease, beta-glucoronidase) enzymes in the macrophages decreased and the activity of redox (succinic dehydrogenase, NAD-N2-diaphorase) enzymes became intensified. A fall of catepsin activity in the CPE of mice 30 minutes after the intraperitoneal administration of the antigens was accompanied by its activation in the cells of the spleen.
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PMID:[General regularities of the macrophage reaction in the administration of various antigens and the phagocytosis of microorganisms]. 126 63

Mycotic foci were studied histochemically on various experimental models of candidiasis. NAD-H, NADP-H-diaphorase, acid phosphatase and ATPase were revealed in the fungi, the activity of these enzymes depended on the state of the fungus. Diaphorase activity in the mucous membrane epithelium falls only if it is damaged by massive invasion of pseudo-mycelium. Inhibition of the enzyme activity in the visceral foci (kidney, liver, heart) occurs only in case of pronounced destruction and is not observed at the distance from the fungi. The results do not confirm the idea of fungal secretion of mycotoxins penetrating into the surrounding tissues and damaging them.
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PMID:[Histochemical study of lesions in superficial and visceral candidiasis]. 129 70

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

The anthraquinone-based antitumour agents mitoxantrone, daunorubicin and ametantrone were found to be substrates for NAD(P)H (quinone acceptor) oxidoreductase (DT-diaphorase) [QAO] isolated from rat liver. This was indicated by the stimulation of QAO-dependent NADPH oxidation by these agents. This effect followed Michaelis-Menten kinetics and was dependent on the concentration of QAO, inhibited by the specific QAO inhibitor dicumarol (15 microM) and enhanced by the QAO activators bovine serum albumin (0.01%) and Triton X-100 (0.03%). As indicated by the Vmax/Km ratio, mitoxantrone (26.53) was considerably more active than ametantrone (11.25) or daunorubicin (7.35). Metabolism of these anthraquinones was associated with the formation of superoxide anions, hydrogen peroxide and hydroxyl radicals as indicated by electron spin resonance spin trapping studies with 5,5-dimethyl-1-pyrroline-N-oxide. This is likely to be due to the slow auto-oxidation of the respective dihydroquinones in the presence of molecular oxygen. QAO needs to be considered as a possible route of bioreductive activation of these agents.
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PMID:NAD(P)H (quinone acceptor) oxidoreductase (DT-diaphorase)-mediated two-electron reduction of anthraquinone-based antitumour agents and generation of hydroxyl radicals. 131 84


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