The Key laboratory of Geriatrics, Beijing Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, National Health Commission, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P. R. China.
Cardiovascular Department, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, P. R. China.
Pharmacol Res Perspect. 2021 Feb;9(1):e00718. doi: 10.1002/prp2.718.
Cytochrome P450 2C9 (CYP2C9) is one of the most important drugs metabolizing enzymes and accounts for the metabolism of about 13%-17% of clinical drugs. Like other members in CYP2 family, CYP2C9 gene exhibits great genetic polymorphism among different races and individuals. CYP2C918 is one CYP2C9 allelic variant identified in a Southeast Asian population and is estimated to cause the amino acid substitutions of I359L and D397A in CYP2C9 enzyme simultaneously. Limited by the low expression level in bacteria and COS-7 cells, no valuable enzyme kinetics have been reported on this CYP2C9 variant. In this study, the baculovirus-based system was used for the high expression of recombinant CYP2C9 s in insect cells. As a result, together with I359L substitution, D397A could significantly decrease the protein expression of CYP2C9.18 in insect cells, although substitution of D397A alone had no effect on the expression of CYP2C9 in vitro. As compared with that of wild-type enzyme, both CYP2C9.18 variant and D397A variant could decrease more than 80% of the catalytic activity of CYP2C9 enzyme toward three probe substrates, suggesting that caution should be exercised when patients carrying CYP2C918 taking medicines metabolized by CYP2C9 enzyme with a narrow therapeutic window.
细胞色素 P450 2C9（CYP2C9）是最重要的药物代谢酶之一，约占临床药物代谢的 13%-17%。与 CYP2 家族的其他成员一样，CYP2C9 基因在不同种族和个体之间表现出很大的遗传多态性。CYP2C918 是在东南亚人群中发现的一种 CYP2C9 等位基因变异体，据估计会导致 CYP2C9 酶中同时发生 I359L 和 D397A 的氨基酸取代。由于在细菌和 COS-7 细胞中的低表达水平，目前尚未报道关于该 CYP2C9 变异体的有价值的酶动力学数据。在本研究中，使用杆状病毒系统在昆虫细胞中高表达重组 CYP2C9 s。结果表明，与 I359L 取代一起，D397A 可显著降低昆虫细胞中 CYP2C9.18 的蛋白表达，尽管单独取代 D397A 对体外 CYP2C9 的表达没有影响。与野生型酶相比，CYP2C9.18 变异体和 D397A 变异体均可使 CYP2C9 酶对三种探针底物的催化活性降低 80%以上，提示携带 CYP2C918 的患者在使用 CYP2C9 酶代谢的治疗窗较窄的药物时应谨慎。
