title: Characterization of pirenzepine interaction with cytochrome P-450.
abstract: Pirenzepine interacts with the haem iron of cytochrome P-450 from rat-and pig-liver microsomes, to give absorption spectra with max. at 424-429 nm, and min. at 391-399 nm. Binding to cytochrome P-450 was not detected with human-liver microsomes. Inhibition of 7-ethoxycoumarin dealkylation by pirenzepine using rat-liver microsomes gave values of I50 = 5 mM and Kis = 0.53 mM. E.p.r. spectra showed that pirenzepine probably interacts with the haem iron through the pirenzepine N-4(1) tertiary amine group.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000293:Adolescent; D000818:Animals; D001570:Benzodiazepinones / Q000378:metabolism* / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D006418:Heme / Q000378:metabolism; D006801:Humans; D008024:Ligands / Q000378:metabolism; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D010105:Oxygenases / Q000037:antagonists & inhibitors; D010634:Phenobarbital / Q000494:pharmacology; D010890:Pirenzepine; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013379:Substrate Specificity; D013552:Swine
chemical_list: D001570:Benzodiazepinones; D008024:Ligands; D010890:Pirenzepine; D006418:Heme; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; D010634:Phenobarbital