PT  - JOURNAL ARTICLE
AU  - Tamihide Matsunaga
AU  - Nobuyuki Kishi
AU  - Hiroyuki Tanaka
AU  - Kazuhito Watanabe
AU  - Hidetoshi Yoshimura
AU  - Ikuo Yamamoto
TI  - Major Cytochrome P450 Enzyme Responsible for Oxidation of Secondary Alcohols to the Corresponding Ketones in Mouse Hepatic Microsomes
DP  - 1998 Oct 01
TA  - Drug Metabolism and Disposition
PG  - 1045--1047
VI  - 26
IP  - 10
4099  - http://dmd.aspetjournals.org/content/26/10/1045.short
4100  - http://dmd.aspetjournals.org/content/26/10/1045.full
SO  - Drug Metab Dispos1998 Oct 01; 26
AB  - The oxidative activities of 7α- and 7β-hydroxy-Δ8-tetrahydrocannabinol (7α- and 7β-hydroxy-Δ8-THC) to 7-oxo-Δ8-THC in hepatic microsomes of mice were significantly increased by the treatment of mice with dexamethasone or phenobarbital. A cytochrome P450 enzyme, named P450MDX-B, was purified from hepatic microsomes of dexamethasone-treated mice, and its apparent molecular mass was estimated to be 51,000. The NH2-terminal amino acid sequence of P450MDX-B was the same as that of CYP3A11. The oxidative activities of 7α- and 7β-hydroxy-Δ8-THC were 2.55 and 4.92 nmol/min/nmol P450, respectively. The antibody against P450MDX-B almost completely inhibited the oxidative activities of 7α- and 7β-hydroxy-Δ8-THC in mice. These results indicate that P450MDX-B (CYP3A11) is a major enzyme responsible for the oxidation of 7α- and 7β-hydroxy-Δ8-THC to 7-oxo-Δ8-THC in mouse liver. The American Society for Pharmacology and Experimental Therapeutics