Title: Identification and Functional Assessment of a New CYP2C9 Allelic Variant CYP2C9*59. | Journal: Drug metabolism and disposition: the biological fate of chemicals. 2015 Aug;43(8):1246-9 | Authors: Dai DP, Wang SH, Li CB, Geng PW, Cai J, Wang H, Hu GX, Cai JP. | Abstract: CYP2C9, one of the most important drug-metabolizing enzymes, is responsible for metabolizing approximately 15% of clinically important drugs, including warfarin, diclofenac, and losartan. Similar to other CYP members, human CYP2C9 exhibits marked genetic polymorphisms among individuals of different ethnicities. In this study, a novel missense mutation (1300A>T) was identified in a warfarin-sensitive patient after a genetic screen of three candidate genes related to high variability in response to warfarin doses. This base transversion leads to an Ile-to-Phe amino acid substitution at codon 434 within the CYP2C9 protein, and this new variant has been named a novel allele, CYP2C9*59, by the Human CYP Allele Nomenclature Committee (http://www.cypalleles.ki.se/cyp2c9.htm). The exogenous expression of CYP2C9.59 in insect cell microsomes revealed that, despite a similar protein expression level as wild-type CYP2C9, variant CYP2C9.59 exhibited significantly reduced maximal velocity, Vmax, and/or increased Michaelis constant, Km, values toward three CYP2C9-specific substrates. Our data suggest that the 1300A>T mutation can greatly decrease the enzymatic activity of the CYP2C9 protein both in vitro and in vivo. | See full PubMed entry: http://www.ncbi.nlm.nih.gov/pubmed/25994031 |
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