Synthesis and evaluation of chloromethyl sulfoxides as a new class of selective irreversible cysteine protease inhibitors

The synthesis and biological evaluation of a new class of selective irreversible cysteine protease inhibitors is described. A set of amino acid based chloromethyl sulfoxides was prepared and they were found to inhibit irreversibly the cysteine protease papain. They were selective for cysteine proteases since no inhibition was found for the serine protease chymotrypsin.