Several analytical techniques based upon the use of substrate-polyacrylamid
e gel electrophoresis were evaluated to achieve characterization of asparta
te proteases in fish stomach. Since aspartate proteases of fish are more st
able at high pH than mammalian pepsins, the most accurate technique for act
ivity assessment is electrophoresis at neutral pH and revealing of such act
ivity at low pH with hemoglobin as substrate. The technique is suitable for
characterization of proteases and in comparative assessment of acid protea
se activity in different sparids. (C) 1998 Elsevier Science Inc. All rights
reserved.