Activity-Based Protein Profiling Reveals Broad Reactivity of the Nerve Agent Sarin

Elucidation of noncholinesterase protein targets of organophosphates, and nerve agents in particular, may reveal additional mechanisms for their high toxicity as well as clues for novel therapeutic approaches toward intoxications with these agents. Within this framework, we here describe the synthesis of the activity-based probe 3, which contains a phosphonofluoridate moiety, a P-Me moiety, and a biotinylated O-alkyl group, and its use in activity-based protein profiling with two relevant biological samples, that is, rhesus monkey liver and cultured human A549 lung cells. In this way, we have unearthed eight serine hydrolases (fatty acid synthase, acylpeptide hydrolase, dipeptidyl peptidase 9, prolyl oligopeptidase, carboxylesterase, long-chain acyl coenzyme A thioesterase, PAF acetylhydrolase 1b, and esterase D/S-formyl glutathione hydrolase) as targets that are modified by the nerve agent sarin. It is also shown that the newly developed probe 3 might find its way into the development of alternative, less laborious purification protocols for human butyrylcholinesterase, a potent bioscavenger currently under clinical investigation as a prophylactic/therapeutic for nerve agent intoxications.