Catalytic Activities of Crude Enzyme Fractions from Monterey Sardine

Catalytic activities in sarcoplasmic fluid of Monterey sardine ( Sardinops sagax caerulea ) were identified. Hydrolysis at pH 7.6 on hippuryl‐L‐phenylalanine and hippuryl‐L‐arginine suggested the presence of carboxypeptidase A and B. Proteolysis on glutaryl‐L‐phenylalanine‐p‐nitroanilide, and inhibition by CuSO 4 , phenylmethylsulfonyl fluoride and N‐p‐tosyl‐L‐lysil chloromethyl ketone, confirmed presence of a chymotrypsin‐like proteinase and other serine enzymes. No hydrolysis on α‐N‐benzoyl‐D,L‐arginine‐p‐nitroanilide occurred. Leucine aminopeptidase was detected by hydrolysis on L‐leucyl‐β‐naplithylamide‐HCl. Activity at pH 3 proved the presence of an acid proteinase but a slight inhibition by EDTA suggested the involvement of a cathepsin D‐like enzyme. Cathepsins A and B and collagenase were not detected.