Human Liver Microsomal Cytochrome P450 3A Enzymes Involved in Thalidomide 5-Hydroxylation and Formation of a Glutathione Conjugate
Human Liver Microsomal Cytochrome P450 3A Enzymes Involved in Thalidomide 5-Hydroxylation and Formation of a Glutathione Conjugate
复制标题
DOI：
10.1021/tx900367p
复制
发表时间：
2010-06-01
影响因子：
4.1
通讯作者：
Yamazaki, Hiroshi
中科院分区：
文献类型：
--
作者：
Chowdhury, Goutam;Murayama, Norie;Yamazaki, Hiroshi
NADPH强化的人和猴肝微粒体将（R）-沙利度胺氧化为5-羟基沙利度胺和5 '-羟基沙利度胺。（R）-沙利度胺比（S）-沙利度胺更有效地羟基化。重组人P450 3A 4、3A 5和3A 7以及猴P450 3A 8和3A 5（与细菌膜中的NADPH-P450还原酶共表达）也催化（R）-沙利度胺5-羟基化。纯化的人P450 2C 19、3A 4和3A 5在重构系统中以相似速率介导（R）-沙利度胺5-羟基化。P450 2C 19显示出相当不饱和的底物-速度曲线;然而，P450 3A 4和3A 5显示出S形曲线。P450还将5-羟基沙利度胺氧化成环氧化物或二羟基化合物。液相色谱质谱分析显示，在谷胱甘肽存在下，肝微粒体P450 3A 4和3A 5催化（R）-和（S）-5-羟基沙利度胺形成谷胱甘肽结合物（指定为苯环上形成的5-羟基沙利度胺结合物）。这些结果表明，人P450 3A 4和3A 5介导沙利度胺5-羟基化和进一步氧化，导致谷胱甘肽缀合物，这可能与沙利度胺的药理学和毒理学作用有关。
(R)-Thalidomide was oxidized to 5-hydroxythalidomide and 5'-hydroxythalidomide by NADPH-fortified liver microsomes from humans and monkeys. (R)-Thalidomide was hydroxylated more efficiently than (S)-thalidomide. Recombinant human P450s 3A4, 3A5, and 3A7 and monkey P450s 3A8 and 3A5 (coexpressed with NADPH-P450 reductase in bacterial membranes) also catalyzed (R)-thalidomide 5-hydroxylation. Purified human P450s 2C19, 3A4, and 3A5 mediated (R)-thalidomide 5-hydroxylation at similar rates in reconstituted systems. P450 2C19 showed a rather nonsaturable substrate-velocity curve; however, P450s 3A4 and 3A5 showed sigmoidal curves. P450 also oxidized 5-hydroxythalidomide to an epoxide or dihydroxy compound. Liquid chromatography mass spectrometry analysis revealed the formation of a glutathione conjugate from (R)- and (S)-5-hydroxythalidomide, catalyzed by liver microsomal P450s 3A4 and 3A5 in the presence of glutathione (assigned as a conjugate of 5-hydroxythalidomide formed on the phenyl ring). These results indicate that human P450s 3A4 and 3A5 mediate thalidomide 5-hydroxylation and further oxidation leading to a glutathione conjugate, which may he of relevance in the pharmacological and toxicological actions of thalidomide.