PROTEIN INHIBITORS OF PROTEOLYTIC-ENZYMES

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