title: Regio- and stereoselective oxidation of propranolol enantiomers by human CYP2D6, cynomolgus monkey CYP2D17 and marmoset CYP2D19.
abstract: Toxic and pharmacokinetic profiles of drug candidates are evaluated in vivo often using monkeys as experimental animals, and the data obtained are extrapolated to humans. Well understanding physiological properties, including drug-metabolizing enzymes, of monkeys should increase the accuracy of the extrapolation. The present study was performed to compare regio- and stereoselectivity in the oxidation of propranolol (PL), a chiral substrate, by cytochrome P450 2D (CYP2D) enzymes among humans, cynomolgus monkeys and marmosets. Complimentary DNAs encoding human CYP2D6, cynomolgus monkey CYP2D17 and marmoset CYP2D19 were cloned, and their proteins expressed in a yeast cell expression system. The regio- and stereoselective oxidation of PL enantiomers by yeast cell microsomal fractions were compared. In terms of efficiency of expression in the system, the holo-proteins ranked CYP2D6=CYP2D17>>CYP2D19. This may be caused by the bulky side chain of the amino acid residue at position 119 (leucine for CYP2D19 vs. valine for CYP2D6 and CYP2D17), which can disturb the incorporation of the heme moiety into the active-site cavity. PL enantiomers were oxidized by all of the enzymes mainly into 4-hydroxyproranolol (4-OH-PL), followed by 5-OH-PL and N-desisopropylpropranolol (NDP). In the kinetic analysis, apparent K(m) values were commonly in the μM range and substrate enantioselectivity of R-PL<S-PL was observed in both K(m) and V(max) values for the formation of the three metabolites from PL enantiomers. The activity to produce NDP tended to be higher for the monkey enzymes, particularly CYP2D17, than for the human enzyme. These results indicate that in the oxidation of PL enantiomers by CYP2D enzymes, stereoselectivity is similar but regioselectivity is different between humans and monkeys.
authors.affiliation: Okayama University, Kita-ku, Japan. shizuo@pharm.okayama-u.ac.jp
authors.forename: Shizuo
authors.initials: S
authors.lastname: Narimatsu
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Nakata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimizudani
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Nagaoka
authors.forename: Hironori
authors.initials: H
authors.lastname: Nakura
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Masuda
authors.forename: Takashi
authors.initials: T
authors.lastname: Katsu
authors.forename: Akiko
authors.initials: A
authors.lastname: Koeda
authors.forename: Shinsaku
authors.initials: S
authors.lastname: Naito
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yamano
authors.forename: Atsuro
authors.initials: A
authors.lastname: Miyata
authors.forename: Nobumitsu
authors.initials: N
authors.lastname: Hanioka
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism*; D002144:Callithrix; D020134:Catalytic Domain; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D007930:Leucine / Q000737:chemistry / Q000378:metabolism; D008252:Macaca fascicularis; D008862:Microsomes, Liver / Q000201:enzymology; D010084:Oxidation-Reduction; D011433:Propranolol / Q000031:analogs & derivatives / Q000737:chemistry* / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity; D014633:Valine / Q000737:chemistry / Q000378:metabolism
chemical_list: D011433:Propranolol; D001189:Aryl Hydrocarbon Hydroxylases; D019389:Cytochrome P-450 CYP2D6; C105144:cytochrome P-450 CYP2D19 (marmoset); D007930:Leucine; D014633:Valine