title: [Determination of phenathrene-9,10-epoxidase in the liver microsomes of rats. The effect of induction on the activity of the enzyme].
abstract: A new method for determination of the activity of phenanthrene-9,10-epoxidase, one of the monoxygenases of the system of drug metabolism, in rat liver microsomes was developed. The method includes the use of phenanthrene as substrate. The rate of the substrate epoxidation is measured with the help of HPLC reverse phase in accordance with the method of the internal standard (1-naphthol) by 9,10-dihydroxy-9,10-dihydrophenanthrene, a product of the intermediate epoxide hydrolysis. For rapid quantitative conversion of the formed 9,10-epoxy-9,10-dihydrophenanthrene endogenic epoxide hydrolase is used after selective termination of the monoxygenase reaction. The time of the assay by HPLC is 4.5 minutes. Phenobarbital is a more strong and selective inductor of this form of cytochrome P-450 than 3-methylcholanthrene. The simultaneous use of the two inductors does not result in additive increasing of the enzyme activity.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D002851:Chromatography, High Pressure Liquid; D003902:Detergents / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D010088:Oxidoreductases / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D010616:Phenanthrenes / Q000032:analysis* / Q000378:metabolism; D010634:Phenobarbital / Q000494:pharmacology; D000077423:Polidocanol; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D003902:Detergents; D010616:Phenanthrenes; D000077423:Polidocanol; D011092:Polyethylene Glycols; D008748:Methylcholanthrene; D010088:Oxidoreductases; C023111:epoxidase; D001189:Aryl Hydrocarbon Hydroxylases; C049008:phenanthrene-9,10-epoxidase; D010634:Phenobarbital
vernacular_title: Opredelenie aktivnosti fenatren-9,10-époksidazy v mikrosomakh pecheni krys. Vliianie induktsii na aktivnost' fermenta.