title: [Catalytic activity of cytochrome P-448 in native and reconstituted microsomal membranes].
abstract: The dependence of oxidative activity of a microsomal monooxygenase system on the ratio of its constituent enzymes--cytochrome P-448 and NADPH-cytochrome P-450 reductase--was investigated. Two approaches for preparation of microsomal membranes with different contents of cytochrome P-448 were used, i. e., time-dependent induction by 3-methylcholanthrene and reconstitution of microsomal membranes by self-assembly from a mixture of solubilized microsomes of intact and methylcholanthrene-induced rats. Using antibodies against cytochrome P-448, the cytochrome P-448 content in native and reconstituted microsomal membranes and its participation in hydroxylation of benz(a)pyrene was determined. It was shown that benz(a)pyrene is hydroxylated in a membrane microsomal monooxygenase system more effectively, when the ratio of NADPH-cytochrome P-450 reductase to cytochrome P-448 is 1: 3 to 1: 6.
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000378:metabolism; D002384:Catalysis; D019388:Cytochrome P-450 CYP1A2; D003580:Cytochromes / Q000378:metabolism*; D006900:Hydroxylation; D007425:Intracellular Membranes / Q000201:enzymology; D008748:Methylcholanthrene / Q000494:pharmacology; D008862:Microsomes, Liver / Q000201:enzymology*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D003580:Cytochromes; D001564:Benzo(a)pyrene; D008748:Methylcholanthrene; C017170:Cyp1a2 protein, rat; D019388:Cytochrome P-450 CYP1A2; D009251:NADPH-Ferrihemoprotein Reductase
vernacular_title: Kataliticheskaia aktivnost' tsitokhroma P-448 v nativnykh i rekonstruirovannykh mikrosomnykh membranakh.