title: Aminopyrine-N-demethylase. II. Characterization of a unique monooxygenase isoform P-450ap.
abstract: A previously unidentified cytochrome P-450ap possessing the highest aminopyrine-N-demethylase activity has been isolated from liver microsomes of 4-isopropylaminoantipyrine-induced rats, using affinity chromatography in combination with ion-exchange chromatography with subsequent separation on a hydroxyapatite column. The isolated cytochrome P-450ap has the following characteristics: Mr = 49 kD, CO-peak maximum at 450.5 nm, rate of demethylation in a reconstituted system for aminopyrine of 25.5 nmoles of HCHO/min per nmole of P-450, and for benzphetamine a rate of 17.0 nmoles of HCHO/min per nmole of P-450. The hemoprotein synthesis is paralleled by the synthesis of a protein with Mr of 51 kD. Immunochemical analysis permitted the identification of the latter protein as cytochrome P-450b. It was, demonstrated that cytochrome P-450ap does not interact with the antibodies to the major phenobarbital induced form, i.e. with cytochrome P-450b.
authors.affiliation: Laboratory of Xenobiochemistry, Academy of Medical Sciences, Siberian Division, Novosibirsk, USSR.
authors.forename: I B
authors.initials: IB
authors.lastname: Tsyrlov
authors.forename: K E
authors.initials: KE
authors.lastname: Gerasimov
mesh_terms: D000632:Aminopyrine / Q000378:metabolism; D000633:Aminopyrine N-Demethylase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002852:Chromatography, Ion Exchange; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005779:Immunodiffusion; D008297:Male; D008745:Methylation; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology; D008970:Molecular Weight; D051381:Rats; D011919:Rats, Inbred Strains; D012521:Sarcosine / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000632:Aminopyrine; C025231:sarkosyl; D003577:Cytochrome P-450 Enzyme System; D000633:Aminopyrine N-Demethylase; D012521:Sarcosine