Based on comparisons of amino acid sequences and the ability to hydrolyse chymotrypsin substrates, we identified a serine protease isolated from P. californiensis as a chymotrypsin. Compared to bovine chymotrypsin, shrimp chymotrypsin is more stable at
higher temperatures (50 C); sensitive to low pH, possesses an acidic pI and, is activated by calcium. The mature enzyme is a single polypeptide chain, activated in a single step. These characteristics match the primary structure and have implications for
post-harvest properties and biotechnological uses, including food processing. Structural features and broad substrate specificity,including chymotryptic and collagenolytic activity, of the P. californiensis protease, have been demonstrated and linked to its primary
structure.