Measuring and quantifying the binding of a drug to a protein target inside living cells and thereby correlating biochemical or biophysical activity with target engagement in cells or tissue represents a key step in target validation and drug development. A prototypic target engagement assay should allow for unbiased determination of small molecule-protein interactions in order to confirm cellular mechanism-of-action (MoA) while avoiding major artificial perturbations of cellular homeostasis and integrity. Recently, several new additions to the chemical biology toolbox have expanded our ability to study drug action in intact cells and enabled surveying of intracellular residence time and binding kinetics, which are particularly important for potent receptor ligands and therapeutic moieties with limited therapeutic index.

中文翻译：

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量化细胞中药物靶标参与度的重要性。

测量和定量药物与活细胞内蛋白质靶标的结合，从而使生物化学或生物物理活性与靶标在细胞或组织中的结合相关联，是靶标验证和药物开发中的关键步骤。原型靶标参与试验应允许小分子-蛋白质相互作用的无偏确定，以便确认细胞作用机制（MoA），同时避免细胞稳态和完整性的主要人为干扰。最近，化学生物学工具箱中的几个新功能扩展了我们研究完整细胞中药物作用的能力，并使我们能够研究细胞内停留时间和结合动力学，这对于有限的治疗指数的有效受体配体和治疗部分尤其重要。