Proteoltyic activities in the digestive tract of anchovy ( Engraulis encrasicholus)

Abstract

1. 1. A survey was made of the distribution of protease activities in the digestive tract of anchovy and its role in protein digestion. 2. 2. A major proteolytic activity in the alkaline range, with a maximum at pH 9.5, and a minor in the acid range, with a maximum at pH 3.0, was detected. 3. 3. High levels of trypsin, chymotrypsin, elastase and aminopeptidase activities were present in pyloric caeca and intestine of anchovies. The levels of carboxypeptidase A and B activities were very low. 4. 4. Serine proteases, mainly trypsin and chymotrypsin, seemed to play a decisive role in protein digestion. 5. 5. Myofibrillar proteins were efficiently degraded by trypsin and the contribution of other proteases to the degradation of myofibrillar protein strongly depended on the presence of trypsin.