Comparison of catalytical activity and stereoselectivity CYP2D6.pdf

ORIGINAL ARTICLES College of Pharmaceutical Sciences1, Zhejiang University; Institute of Quality Standards for Agricultural Products2, Zhejiang Academy of Agricultural Sciences, Hangzhou, PR China Comparison of catalytical activity and stereoselectivity between the recombinant human cytochrome P450 2D6.1 and 2D6.10 L.M. Kong1,*, M.R. Qian1,2,*, H. H. Hu1, S. Y. Xu1, L. S. Yu1, H. D. Jiang1, S. Q. Chen1, S. Zeng1 Received August 29, 2011, accepted October 4, 2011 Prof. Zeng Su, Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmacy, Zhejiang University, Hangzhou 310058, China zengsu@ ? These authors contributed equally to this work. Pharmazie 67: 1–8 (2012) doi: 10.1691/ph.2012.1128 Polymorphisms of the cytochrome P450 2D6 (CYP2D6) gene play a major role in pharmacoki- netic variability in human, while CYP2D6*10 is an important subtype in Asian people. In this study, the co-expression enzyme of human recombinant CYPOR, CYPb5 and CYP2D6.1 or CYP2D6.10 with the Bac-to-BacTM system in baculovirus-infected insect cells was used to study the catalytical activity to imipramine metabolism and stereoselective metabolism of propranolol. The metabolites of imipramine were identified of hydroxyl imipramine and desipramine by LC-MS/MS. There are some dif- ferences between CYP2D6.1 and CYP2D6.10 activity. The kinetics parameters Km, Vmax, and CLint are 11.77±0.91 mol/L, 0.4235±0.05 nmol/nmol CYP2D6.1/min and 3.60×10?5 ml/min/nmol CYP2D6.1 (n = 3) for CYP2D6*1, respectively, and 9.05±0.87 mol/L, 0.42±0.03 nmol/nmol CYP2D6.10/min, and 4.60×10?5 ml/min/nmol CYP2D6.10 (n = 3) for CYP2D6.10. For propranolol, two metabolites were identi- fied to be hydroxyl and N-desisopropylation propranolol by LC-MS/MS. When the substrate concentration was 0.20 mol/L, CYP2D6.1 and CYP2D6.10 exhibited significant stereoseletivity. Furthermore, enan- tioselective formation has been detected. Both of CYP2D6.1 and CYP2D6.10 produced more hydroxyl propranolol from the R-(+)-isom