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)

Bernofsky, Carl (The University of Kansas, Kansas City), and Russell C. Mills. Diaphorases from Aerobacter aerogenes. J. Bacteriol. 92:1404-1414. 1966.-Five enzymes which catalyze the reduction of 2,6-dichlorophenol-indophenol by reduced nicotinamide adenine dinucleotide (NADH(2)) have been separated from sonic extracts of Aerobacter aerogenes B199 by diethylaminoethyl (DEAE) cellulose chromatography. Three major chromatographic fractions (enzymes I, II, and III) account for most of the activity in the extract. Of the two minor fractions, one is associated with cytochrome b(1). The other is extremely labile, and was not studied further. The chromatographed diaphorases appear to have a specific requirement for flavin mononucleotide. They are also readily inactivated by dilution; however, this can be prevented by a combination of phosphate buffer, bovine serum albumin, and flavin mononucleotide. The different enzymes are clearly distinguishable by their activities with NADH(2) and reduced nicotinamide adenine dinucleotide phosphate (NADPH(2)) in the presence of various electron acceptors (2,6-dichlorophenol-indophenol, ferricyanide, menadione, and cytochrome c), and by their responses to inhibitors (amobarbital, antimycin A, Atabrine, p-chloromercuribenzenesulfonate, dicumarol, and 2,4-dinitrophenol). With 2,6-dichlorophenol-indophenol as acceptor, enzymes I, II, and III have comparable activities with either NADH(2) or NADPH(2). With menadione and ferricyanide as acceptors, enzymes II and III exhibit very high, NADH(2)-specific activities. When cytochrome c is the acceptor, however, enzyme III shows greater activity with NADPH(2) as the electron donor. Ferricyanide is the most active acceptor for the cytochrome b(1)-containing fraction. Coenzyme Q(6) does not appear to serve as an acceptor. All the diaphorases, with the exception of that in the cytochrome b(1)-containing fraction, are inhibited by p-chloromercuribenzenesulfonate. Amobarbital is relatively ineffective and inhibits only the indophenol reductase activity of enzyme I. The menadione reductase activity of enzymes I, and II, and the diaphorases in the cytochrome b(1)-containing fraction are strongly inhibited by antimycin A, 2,4-dinitrophenol, dicumarol, and Atabrine. However, the menadione reductase activity of enzyme III is affected only by the last three of these inhibitors. The diaphorases in sonic-treated extracts do not appear to be associated with a particulate fraction.
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PMID:Diaphorases from Aerobacter aerogenes. 592 71

VanDemark, P. J. (University of South Dakota, Vermillion), and P. F. Smith. Respiratory pathways in the Mycoplasma. II. Pathway of electron transport during oxidation of reduced nicotinamide adenine dinucleotide by Mycoplasma hominis. J. Bacteriol. 88:122-129. 1964.-Unlike the flavin-terminated respiratory pathway of the fermentative Mycoplasma, the respiratory chain of the nonfermentative M. hominis strain 07 appears to be more complex, involving quinones and cytochromes in addition to flavins. In addition to reduction by reduced nicotine adenine dinucleotide (NADH) and reduced nicotine adenine dinucleotide phosphate, nonpyridine nucleotide-linked reduction of the respiratory chain of this organism occurred with succinate, lactate, and short-chained acyl coenzyme A derivatives as electron donors. Enzymes catalyzing the oxidation of NADH included an NADH oxidase, a diaphorase, a quinone reductase, and a cytochrome c reductase. The oxidation of NADH was sensitive to a variety of inhibitors, including 10(-4)m Atabrine, 10(-3)m sodium amytal, 10(-5)mp-chloromercuribenzoate, 10(-4)m antimycin A, and 10(-4)m potassium cyanide. The oxidase was resolved by the addition of 5% trichloroacetic acid and reactivated by the addition of flavin adenine dinucleotide but not flavin mononucleotide. The M. hominis sonic extract contained an NADH-coenzyme Q reductase. The oxidation of NADH was stimulated by the addition of either menadione or vitamin K(2) (C(35)). The oxidase was inactivated by extraction with ether or irradiation at 360 mmu. The ether-inactivated enzyme was partially reactivated by the addition of "lipid" extract of the enzyme and coenzyme Q(6). Difference spectra of the cell extracts revealed the presence of "b" and "a" type cytochromes. These cell extracts were found to contain a cyanide-and azide-sensitive cytochrome oxidase and catalase.
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PMID:RESPIRATORY PATHWAYS IN THE MYCOPLASMA. II. PATHWAY OF ELECTRON TRANSPORT DURING OXIDATION OF REDUCED NICOTINAMIDE ADENINE DINUCLEOTIDE BY MYCOPLASMA HOMINIS. 1419 76