Design, synthesis, and evaluation of cell permeable probes for protein kinases

We have explored a novel molecular framework with a lysine core to prepare a probe library for protein kinases. Active site-directed probes, identified through screening of the library, displayed desirable labelling properties, including target specificity, good linear response to the corresponding enzymatic activity and cell permeability. Finally, a two-stage protocol utilizing the newly developed probe with an immunoprecipitation step was successfully established to monitor intracellular Src kinase activity in RK3E-v-Src cells.