Synthetic analogues of the proteinase inhibitor: chymostatin.

Putative proteinase inhibitors with the general structure Z. Arg. X.Phe.H (where X = Leu, Ile or Val) were prepared by solution synthesis using semicarbazone protection for the aldehyde function. These inhibitors showed strong activity towards chymotrypsin whereas the semicarbazones and dipeptides aldehydes showed considerably reduced activity. The structural requirements for inhibition would seem to mimic those of the natural chymotrypsin inhibitor chymostatin.