Polymorphic variants (CYP2C9*3 and CYP2C9*5) and the F114L active site mutation of CYP2C9: Effect on atypical, kinetic metabolism profiles
Polymorphic variants (CYP2C9*3 and CYP2C9*5) and the F114L active site mutation of CYP2C9: Effect on atypical, kinetic metabolism profiles
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DOI：
10.1124/dmd.30.4.385
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发表时间：
2002-04-01
影响因子：
3.9
通讯作者：
Dickman, LJ
中科院分区：
文献类型：
--
作者：
Tracy, TS;Hutzler, JM;Dickman, LJ
CYP 2C 9野生型蛋白已显示出非典型代谢动力学特征，可能影响药物开发过程中的体外-体内预测。先前的工作表明CYP 2C 9多态性变体对代谢速率的底物依赖性影响;然而，假设这些活性位点氨基酸变化也会影响药物代谢的动力学特征。为此，使用纯化的CYP 2C 9 *1（野生型）和涉及活性位点氨基酸变化的变体（包括天然存在的变体CYP 2C 9 *3（Leu 359）和CYP 2C 9 *5（Glu 360）以及人造突变体CYP 2C 9 F114 L）研究了三种模型CYP 2C 9底物（氟比洛芬、萘普生和吡罗昔康）的动力学特征。CYP 2C 9 *1（野生型）代谢三种化合物中的每一种，其特征反映了典型的双曲线（氟比洛芬）、双相（萘普生）和底物抑制（吡罗昔康）动力学。氟比洛芬的CYP 2C 9 *3代谢再次呈双曲线，萘普生呈线性形式（未观察到饱和），吡罗昔康表现出底物抑制。CYP 2C 9 *6介导的氟比洛芬和吡罗昔康代谢呈双曲线，但与萘普生代谢呈线性。F114 L突变体表现出双曲线动力学曲线的氟比洛芬代谢，线性曲线的萘普生代谢，和底物抑制动力学曲线的吡罗昔康代谢。在所有情况下，除了F114 L介导的吡罗昔康代谢，营业额下降，Km一般增加每个等位基因的变体相比，野生型酶。CYP 2C 9介导代谢的动力学特征似乎依赖于底物和CYP 2C 9等位基因变体，因此对开发过程中进行的药物分布预测具有潜在影响。
CYP2C9 wild-type protein has been shown to exhibit atypical kinetic profiles of metabolism that may affect in vitro-in vivo predictions made during the drug development process. Previous work suggests a substrate-dependent effect of polymorphic variants of CYP2C9 on the rate of metabolism; however, it is hypothesized that these active site amino acid changes will affect the kinetic profile of a drug's metabolism as well. To this end, the kinetic profiles of three model CYP2C9 substrates (flurbiprofen, naproxen, and piroxicam) were studied using purified CYP2C9*1 (wild-type) and variants involving active site amino acid changes, including the naturally occurring variants CYP2C9*3 (Leu359) and CYP2C9*5 (Glu360) and the man-made mutant CYP2C9 F114L. CYP2C9*1 (wild-type) metabolized each of the three compounds with a distinctive profile reflective of typical hyperbolic (flurbiprofen), biphasic (naproxen), and substrate inhibition (piroxicam) kinetics. CYP2C9*3 metabolism was again hyperbolic for flurbiprofen, of a linear form for naproxen (no saturation noted), and exhibited substrate inhibition with piroxicam. CYP2C9*6-mediated metabolism was hyperbolic for flurbiprofen and piroxicam but linear with respect to naproxen turnover. The F114L mutant exhibited a hyperbolic kinetic profile for flurbiprofen metabolism, a linear profile for naproxen metabolism, and a substrate inhibition kinetic profile for piroxicam metabolism. In all cases except F114L-mediated piroxicam metabolism, turnover decreased and the Km generally increased for each allelic variant compared with wild-type enzyme. It seems that the kinetic profile of CYP2C9-mediated metabolism is dependent on both substrate and the CYP2C9 allelic variant, thus having potential ramifications on drug disposition predictions made during the development process.