Rapid Identification of Potent Nonpeptidic Serine Protease Inhibitors

Substrate activity screening was used to rapidly identify a novel and potent (kinact/Ki=59 000 M−1 s−1) nonpeptidic chymotrypsin inhibitor with MW<500. The inhibitor is more potent than the best reported tetrapeptidyl phosphonate chymotrypsin inhibitor and demonstrated selectivity over a panel of other serine proteases, including the closely related enzyme cathepsin G.