A liquid chromatography/mass spectrometry-based method for the selection of ATP competitive kinase inhibitors.

The currently approved kinase inhibitors for therapeutic uses and a number of kinase inhibitors that are undergoing clinical trials are directed toward the adenosine triphosphate (ATP) binding site of protein kinases. The 5'-fluorosulfonylbenzoyl 5'-adenosine (FSBA) is an ATP-affinity reagent that covalently modifies a conserved lysine present in the nucleotide-binding site of most kinases. The authors have developed a liquid chromatography/mass spectrometry-based method to monitor binding of ATP competitive protein kinase inhibitors using FSBA as a nonselective activity-based probe for protein kinases. Their method provides a general, rapid, and reproducible means to screen and validate selective ATP competitive inhibitors of protein kinases.