title: Rat liver cytosolic azoreductase. Purification and characterization.
abstract: An azoreductase has been purified to apparent homogeneity from the hepatic 105,000 x g supernatant fraction of 3-methylcholanthrene-treated rats. In the presence of sodium dodecyl sulfate, the purified enzyme preparation electrophoreses on polyacrylamide gels as a single protein band with a molecular weight of 30,000. In the absence of detergent, chromatography of the azoreductase on Sephadex G-100 gives a molecular weight of about 52,000 suggesting that the native enzyme may exist as a dimer. The purified azoreductase has a typical flavoprotein absorption spectrum and contains 2 mol of FAD/mol of enzyme. The enzyme catalyzes the reductive fission of methyl red (2'-carboxy-4-N,N-dimethylaminoazobenzene) and a structure-activity study indicates that the 2'-carboxyl group of methyl red is essential for catalysis since other structurally related analogs are totally inactive.
mesh_terms: D000818:Animals; D001391:Azo Compounds; D003600:Cytosol / Q000201:enzymology; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008970:Molecular Weight; D009247:NADH, NADPH Oxidoreductases; D051381:Rats; D013379:Substrate Specificity; D004124:p-Dimethylaminoazobenzene / Q000031:analogs & derivatives
chemical_list: D001391:Azo Compounds; D005182:Flavin-Adenine Dinucleotide; D004124:p-Dimethylaminoazobenzene; D009247:NADH, NADPH Oxidoreductases