title: Properties of aryl hydrocarbon (benzo[a]pyrene) hydroxylase in the liver from C3H/He and DBA/2 strains of mice.
abstract: Aryl hydrocarbon hydroxylase activity in liver from the C3H/He strain of mice is apparently increased by the administration of 3-methylcholanthrene, but the enzyme activity from the DBA/2 strain of mice is not. The enzyme activity from female mice is higher than that from male mice, even 72 hr after a single application of 3-methylcholanthrene into the mice. The control enzyme in the liver from both strains of mice has a pH optimum at 7.9 and the induced enzyme from C3H/He mice, at 8.2. There are approximately the same levels of the apparent Km for benzo[a]pyrene, NADPH, or NADH in the liver enzyme from both strains of mice even after treatment with 3-methylcholanthrene. The induced enzyme is inhibited by 7,8- or 5,6-benzoflavone non-competitively, and nicotinamide inhibits both the constitutive and induced enzyme uncompetiviely. Cyclohexene oxide and 1,1,1-trichloropropane oxide, known to be inhbitors of epoxide hydrase, inhibit the activity of the constitutive enzyme, but enhance the induced enzyme in the liver. The difference in the properties between the constitutive and induced enzymes from mouse liver is discussed briefly.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001580:Benzopyrenes / Q000378:metabolism; D003510:Cyclohexanes / Q000494:pharmacology; D053138:Cyclohexenes; D004790:Enzyme Induction; D004851:Epoxide Hydrolases / Q000037:antagonists & inhibitors; D004852:Epoxy Compounds / Q000494:pharmacology; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D006843:Hydrocarbons, Chlorinated / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D008862:Microsomes, Liver / Q000201:enzymology; D009243:NAD / Q000378:metabolism; D009536:Niacinamide / Q000494:pharmacology; D012737:Sex Factors; D013045:Species Specificity
chemical_list: D001580:Benzopyrenes; D003510:Cyclohexanes; D053138:Cyclohexenes; D004852:Epoxy Compounds; D005419:Flavonoids; D006843:Hydrocarbons, Chlorinated; D009243:NAD; C007193:cyclohexene oxide; D009536:Niacinamide; D008748:Methylcholanthrene; D001189:Aryl Hydrocarbon Hydroxylases; D004851:Epoxide Hydrolases