Digestive proteases in juvenile Mexican green abalone, Haliotis fulgens

In this study, proteolytic and specific substrate activities were measured in viscera (VIS) and hepatopancreas (HP) extracts from juvenile green abalo ne, Haliotis fulgens. The soluble protein was more abundant in the hepatopa ncreas than viscera. The HP proteolytic activity was higher than VIS. Prote olytic activity assayed with 1% azocasein and 2% haemoglobin at different p Hs showed that juvenile digestive enzymes have activity peaks at acid pH. I n alkaline pH, both activities decreased. Regardless of the size of the org anism and diet, extracts from hepatopancreas and viscera hydrolysed trypsin , chymotrypsin, and acid phosphatase-specific substrates, but not carboxype ptidase A and B substrates. Specific substrate activities in HP were higher than VIS activity in all groups, except in juveniles fed diatoms in which the VIS trypsin and chymotrypsin activity was higher than the HP activity. (C) 2000 Elsevier Science B.V. All rights reserved.