Stereoselective sulfoxidation of sulindac sulfide by flavin-containing monooxygenases - Comparison of human liver and kidney microsomes and mammalian enzymes
Stereoselective sulfoxidation of sulindac sulfide by flavin-containing monooxygenases - Comparison of human liver and kidney microsomes and mammalian enzymes
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DOI：
10.1016/s0006-2952(00)00301-4
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发表时间：
2000-07-01
影响因子：
5.8
通讯作者：
Hall, SD
中科院分区：
文献类型：
--
作者：
Hamman, MA;Haehner-Daniels, BD;Hall, SD
在人肝脏、肾脏和cDNA表达的酶中表征了舒林酸的代谢活性代谢产物舒林酸硫化物的立体选择性磺基氧化。R-和S-舒林酸亚砜在人肝微粒体（N = 4）中形成舒林酸亚砜的动力学参数估计值（pH = 7.4）分别为V-max = 1.5 +/- 0.50 nmol/min/mg，K-m = 15 +/- 5.1 μ M; V-max = 1.1 +/- 0.36 nmol/min/mg，K-m = 16 +/- 6.1 μ M。肾微粒体（N = 3）产生的R-和S-舒林酸亚砜的参数估计值（pH = 7.4）分别为V-max = 0.9 +/- 0.29 nmol/min/mg，K-m = 15 +/- 2.9 μ M; V-max = 0.5 =/- 0.21 nmol/min/mg，K-m = 22 +/- 1.9 μ M。在人肝脏和含黄素的单加氧酶3（FMO 3）中，R-舒林酸亚砜的V-max在pH = 8.5时增加60-70%，但S-舒林酸亚砜的V-max不变。在14份肝微粒体制备物中，R-舒林酸亚砜形成与免疫定量FMO或尼古丁N-氧化之间存在显著相关性（r = 0.88和0.83; P < 0.01）。R-和S-舒林酸亚砜形成率也与13个肾微粒体样品中免疫定量FMO显著相关（r = 0.85和0.75; P < 0.01）。微粒体的轻度热失活使活性降低30- 60%，并且观察到立体选择性的损失。甲巯咪唑是一种有效的非立体选择性的肝、肾微粒体硫氧化抑制剂。正辛胺和lubrol的膜增溶作用是S-舒林酸亚砜形成的有效和选择性抑制剂，cDNA表达的CYP未能明显地使舒林酸硫化物亚砜化，并且抑制剂在抑制催化活性方面无效。纯化的小型猪肝FMO 1、兔肺FMO 2和人cDNA表达的FMO 3有效地氧化舒林酸硫化物，对R-异构体具有高度的立体选择性，但FMO 5缺乏催化活性。硫化物的亚砜的生物转化主要是由FMO催化，并可能被证明是有用的，在表征FMO活性。生物化学制药60;1：7-17，2000年。(C)2000 Elsevier Science Inc.
The stereoselective sulfoxidation of the pharmacologically active metabolite of sulindac, sulindac sulfide, was characterized in human liver, kidney, and cDNA-expressed enzymes. Kinetic parameter estimates (pH = 7.4) for sulindac sulfoxide formation in human liver microsomes (N = 4) for R- and S-sulindac sulfoxide were V-max = 1.5 +/- 0.50 nmol/min/mg, K-m = 15 +/- 5.1 mu M; and V-max = 1.1 +/- 0.36 nmol/min/mg, K-m = 16 +/- 6.1 mu M, respectively. Kidney microsomes (N = 3) produced parameter estimates (pH = 7.4) of V-max = 0.9 +/- 0.29 nmol/min/mg, K-m = 15 +/- 2.9 mu M; V-max = 0.5 =/- 0.21 nmol/min/mg, K-m = 22 +/- 1.9 mu M for R- and S-sulindac sulfoxide, respectively. In human liver and flavin-containing monooxygenase 3 (FMO3) the V-max for R-sulindac sulfoxide increased 60-70% at pH = 8.5, but for S-sulindac sulfoxide was unchanged. In fourteen liver microsomal preparations, significant correlations occurred between R-sulindac sulfoxide formation and either immunoquantified FMO or nicotine N-oxidation (r = 0.88 and 0.83; P < 0.01). The R- and S-sulindac sulfoxide formation rate also correlated significantly (r = 0.85 and 0.75; P < 0.01) with immunoquantified FMO in thirteen kidney microsomal samples. Mild heat deactivation of microsomes reduced activity by 30-60%, and a loss in stereoselectivity was observed. Methimazore was a potent and nonstereoselective inhibitor of sulfoxidation in liver and kidney microsomes. n-Octylamine and membrane solubilization with lubrol were potent and selective inhibitors of S-sulindac sulfoxide formation, cDNA-expressed CYPs failed to appreciably sulfoxidate sulindac sulfide, and CYP inhibitors were ineffective in suppressing catalytic activity. Purified mini-pig liver FMO1, rabbit lung FMO2, and human cDNA-expressed FMO3 efficiently oxidized sulindac sulfide with a high degree of stereoselectivity towards the R-isomer, but FMO5 lacked catalytic activity. The biotransformation of the sulfide to the sulfoxide is catalyzed predominately by FMOs and may prove to be useful in characterizing FMO activity. BIOCHEM PHARMACOL 60;1:7-17, 2000. (C) 2000 Elsevier Science Inc.