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)

Luminol chemiluminescence was observed by addition of menadione to yeast cell suspension and was amplified 1000-fold by further addition of Fe-complex. Catalase, superoxide dismutase and ceruloplasmin had inhibitory effects on luminol chemiluminescence, indicating the extracellular generation of active oxygens (H2O2 and O2-) and reduction of Fe-complex. The generation of H2O2 and reduction of Fe-complex were mainly dependent on the activity of NADH: menadione oxidoreductase in the plasma membrane and cytosol fractions. Both luminol chemiluminescence and H2O2 production were sensitive to the inhibitory effects of proton conductor, ionophorous antibiotics and ATPase inhibitor rather than the inhibitors of the mitochondria electron transport system. The incubation of glucose with yeast cells caused a parallel increase in luminol chemiluminescence, H2O2 production and intracellular NADH concentration. These facts suggest that menadione-catalyzed H2O2 production and chemiluminescence are used as the indicators of cell activity to keep the NADH concentration and NADH: menadione oxidoreductase activity which may be sensitive to the change in pH and ion concentrations.
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PMID:Extracellular generation of active oxygen species catalyzed by exogenous menadione in yeast cell suspension. 187

This study proposes a novel chemiluminescent assay of bacterial activity. Luminol chemiluminescence (LC) was amplified on addition of menadione to Escherichia coli suspension, and it was effectively inhibited by addition of superoxide dismutase rather than catalase. This fact suggests that H2O2 produced from O2 by superoxide dismutase is decomposed by catalase of E. coli. NAD(P)H:menadione reductase activities in periplasm and cytosol corresponded to the amplification of menadione-catalyzed LC, and outer and cytoplasmic membranes were only slightly involved in the LC. The total activity and Vmax of NAD(P)H:menadione reductase in the cytoplasm were greater than those in the periplasm. A transient increase in menadione-catalyzed LC was observed in the exponential phase and the LC decreased in the stationary phase during growth of E. coli. Menadione-catalyzed LC was sensitive to antibiotic action. A decrease in menadione-catalyzed LC by the impairment of membrane functions and by the inhibition of protein synthesis was observed at 5 min and 3 hr, respectively. These findings suggest the possibility that menadione-catalyzed luminol chemiluminescent assay is applicable to rapid antimicrobial assay because LC is sensitive to the change in growth and cytotoxic events caused by antimicrobial agents.
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PMID:Menadione-catalyzed O2- production by Escherichia coli cells: application of rapid chemiluminescent assay to antimicrobial susceptibility testing. 1147 20