IsoTOP ABPP Experiments

Mino cells were incubated for 2 h with 1 μM compound or DMSO. The cells were lysed and incubated with iodoacetamide-alkyne probe, followed by CuAAC reaction with an isotopically labeled desthiobiotin–valine–azidolysine peptide. Heavy and light probe samples were pooled, precipitated with methanol/chloroform, bound to streptavidin beads, and digested with trypsin, and the streptavidin-bound peptides were analyzed by LC-MSMS. Peptide identification and quantitation were performed using MaxQuant. A detailed description of the experimental procedure and data analysis methods is given in the Supporting Information.