PROTEIN INHIBITORS OF PROTEOLYTIC-ENZYMES

New data on the mechanism of interaction between proteolytic enzymes a nd protein inhibitors are presented. Most of known serine proteinase i nhibitors bind to proteolytic enzymes through a substrate-like mechani sm. A different mechanism is observed in the case of the inhibition of thrombin by hirudin and of papain by cystatin (from egg white) and st ephin b. Protopeptides released during activation of some proteinase z ymogens may act as efficient enzyme inhibitors. Such zymogens can be c onsidered as covalently bound enzyme-inhibitor complexes.