Europium‐Labeled Activity‐Based Probe through Click Chemistry: Absolute Serine Protease Quantification Using ¹⁵³Eu Isotope Dilution ICP/MS

Abstract

Click and analyze: the titled probe was synthesized by conjugating a sulfonyl fluoride and azido unit using click chemistry to give SF-Eu, which can react specifically with serine (Ser) in the active site of serine protease (SP). Combination of the method with (153)Eu-isotope dilution ICP/MS enables absolute protein quantification of active SPs in biological samples using only one (153)Eu(NO(3))(3) isotopic standard.