Proteomic Profiling of Protein Kinase Inhibitor Targets by Mass Spectrometry.

Identifying cellular targets of bioactive small molecules from large-scale screening campaigns can be a significant bottleneck in developing novel therapeutics. Our rapid small-molecule target profiling protocol combines affinity enrichment and SILAC for proteomic identification of small molecule-protein interactions. Selective interactions are easily discernable from nonspecific protein binding by quantitative ratios. Using kinase inhibitors as an example, we provide an optimized protocol featuring on-bead protein digestion and single nano-flow liquid chromatographic-mass spectrometric (LC-MS) analyses, consequently increasing analytical throughput and sensitivity over gel-based sample preparation methods for rapid profiling of kinase inhibitor targets.