Cysteine Protease

Cysteine Protease

Cysteine proteases also known as thiol proteases are enzymes that degrade polypeptides. These proteases share a common catalytic mechanism that involves a nucleophilic cysteine thiol in a catalytic dyad.

Cysteine proteases are commonly encountered in fruits including papaya, pineapple, fig and kiwifruit. The proportion of protease tends to be higher when the fruit is unripe. In fact, dozens of latices of different plant families are known to contain cysteine proteases. Cysteine proteases are used as an ingredient in meat tenderizers.