Chiral sulfonimidoyl fluorides display potent stereoselective inhibition of chymotrypsin

Herein, we present chiral sulfonimidoyl fluorides as enantioselective inhibitors of α-chymotrypsin. After screening a library of 16 racemic sulfonimidoyl fluorides for their inhibitory potential for this well-studied model serine protease, we enantiomerically separated the five best-performing inhibitors and determined the IC 50 values of the enantiomers. We not only find enantioselective inhibition but also that the most potent derivatives are >25 times more active than the established serine protease inhibitor, PMSF. Furthermore, tryptic digestion and mass spectrometry (MS) analysis reveal covalent modification of the active site serine, and molecular docking simulations corroborate the determined IC 50 values. In view of the crucial role of serine proteases in the regulation of many biological processes, we expect that this class of inhibitors can occupy an important place in future endeavors to fight diseases.