Protease activity in walleye pollock muscle which has been infested by parasites

Abstract

Inspections of the skeletal muscle of walleye pollock Theragra chalcogramma caught in Alaska revealed the presence of cysts of an unidentified microsporian and multi-nucleate bodies of lchthyophonus hoferi. This is the first study of the effects of lchthyophonus infestation on the quality of walleye pollock. The infested muscle contained protease, which has the ability to degrade walleye pollock myofibriliar proteins, mainly the myosin heavy chain at temperatures around 50 to 60°C, in vitro. Cysteine protease inhibitors were able to reduce the enzyme activity whereas specific inhibitors of serine proteases and aspartic proteases were ineffective.