Reactive metabolites (RM) formed from bioactivation of drugs can covalently modify liver proteins and cause mechanism-based inactivation of major cytochrome P450 (CYP450) enzymes. Risk of bioactivation of a test compound is routinely examined as part of lead optimization efforts in drug discovery. Here we described a chemoproteomic platform to assess in vitro and in vivo bioactivation potential of drugs. This platform enabled us to determine reactivity of thousands of proteomic cysteines toward RMs of diclofenac formed in human liver microsomes and living animals. We pinpointed numerous reactive cysteines as the targets of RMs of diclofenac, including the active (heme-binding) sites on several key CYP450 isoforms (1A2, 2E1 and 3A4 for human, 2C39 and 3A11 for mouse). This general platform should be applied to other drugs, drug candidates, and xenobiotics with potential hepatoxicity, including environmental organic substances, bioactive natural products, and traditional Chinese medicine.

中文翻译：

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一个化学计量学平台，以评估药物的生物激活潜力

由药物的生物激活形成的反应性代谢产物（RM）可以共价修饰肝蛋白并引起主要细胞色素P450（CYP450）酶的基于机制的失活。作为药物发现中铅优化工作的一部分，常规检查了受试化合物生物活化的风险。在这里，我们描述了一种在体外和体内评估的化学旋转平台药物的生物激活潜力。该平台使我们能够确定数千种蛋白质组半胱氨酸对人肝微粒体和活体动物中形成的双氯芬酸RM的反应性。我们确定了许多反应性半胱氨酸作为双氯芬酸RM的靶标，包括几个关键CYP450同工型（人为1A2、2E1和3A4，小鼠为2C39和3A11）上的活性（血红素结合）位点。该通用平台应适用于其他具有潜在肝毒性的药物，候选药物和异生物素，包括环境有机物质，生物活性天然产物和中药。