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PREDICTION OF DRUG DISPOSITION BY HUMAN DRUG METABOLIZING ENZYMES

通过人体药物代谢酶预测药物分布

基本信息

批准号：
11557191
负责人：
YAMAZAKI Hiroshi
金额：
$ 3.01万
依托单位：
KANAZAWA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11557191/
关键词：
P450 human liver microsomes phenytoin tegafur Individual difference P450 contents coexpressing system drug Interaction チトクロムP450 CYP3A4 組換えヒトP450 NADPH-P450還元酵素チトクロームb5 大腸菌テストステロン

项目摘要

Drug oxidation activities of twelve recombinant human cytochrome P450 (P450) coexpressed with human NADPH-P450 reductase (NPR) in bacterial membranes (P450/NPR membranes) were determined and compared with those of other recombinant systems and of human liver microsomes. Addition of exogenous membrane-bound NPR to the P450/NPR membranes enhanced the catalytic activities of CYP2C8, CYP2C9, CYP2C19, CYP3A4, and CYP3A5 ; however, enhancement of activities of CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, CYP2D6, and CYP2E1 in membranes was not observed after the addition of NPR in 4-molar excess to each P450. Exogenous purified human cytochrome b_5 (b_5) further enhanced catalytic activities of CYP2A6, CYP2B6, CYP2C8, CYP2E1, CYP3A4, and CYP3A5/NPR membranes. Catalytic activities of CYP2C9 and CYP2C19 were enhanced by addition of b_5 in reconstitution systems but not in the P450/NPR membranes. Apo b_5 (devoid of heme) enhanced catalytic activities when added to the both systems, except for CYP2E1/NPR membranes and the reconstituted systems containing purified CYP2C8 or CYP2E1 in comparison with b_5. Catalytic activities in P450/NPR membranes plus b_5 systems were roughly similar to those measured with microsomes of insect cells coexpressing P450 with NPR (and b_5) and/or of human liver microsomes, based on equivalent P450 contents. These results suggest that interactions of P450 and NPR coexpressed in membranes and reconstituted systems appear to be different in some human CYP2 family enzymes, possibly due to a conformational role of b_5. P450/NPR membrane systems containing b_5 are useful models for prediction of the rates for liver microsomal P450-dependent drug oxidations.

测定了12种与人NADPH-P450还原酶（NPR）共表达的重组人细胞色素P450 （P450）在细菌膜（P450/NPR膜）中的药物氧化活性，并与其他重组系统和人肝微粒体的药物氧化活性进行了比较。在P450/NPR膜上加入外源性膜结合NPR增强了CYP2C8、CYP2C9、CYP2C19、CYP3A4和CYP3A5的催化活性；然而，在每个P450中加入4摩尔过量的NPR后，没有观察到膜中CYP1A1、CYP1A2、CYP1B1、CYP2A6、CYP2B6、CYP2D6和CYP2E1的活性增强。外源性纯化的人细胞色素b_5 （b_5）进一步增强了CYP2A6、CYP2B6、CYP2C8、CYP2E1、CYP3A4和CYP3A5/NPR膜的催化活性。在重构体系中添加b_5可增强CYP2C9和CYP2C19的催化活性，而在P450/NPR膜中则无此作用。除了CYP2E1/NPR膜和含有纯化CYP2C8或CYP2E1的重组体系与b_5相比，两种体系中添加Apo b_5（不含血红素）均增强了催化活性。P450/NPR膜加b_5系统的催化活性与共表达P450与NPR（和b_5）的昆虫细胞微粒体和/或人肝微粒体的催化活性大致相似，基于等效的P450含量。这些结果表明，在一些人类CYP2家族酶中，P450和NPR在膜和重组系统中共表达的相互作用似乎是不同的，可能是由于b_5的构象作用。含有b_5的P450/NPR膜系统是预测肝微粒体P450依赖性药物氧化率的有用模型。