Effect of iced-storage on the activity of cathepsin L and trypsin-like protease in carp dorsal muscle

• Cathepsin L and trypsin-like remained in carp meat despite intensive leaching.
• Activity of cathepsin L was affected slightly by the iced storage of 4 days.
• Activity of trypsin-like might be activated during the short term storage in ice.

Carps were stored in ice for 0, 2 and 4 days. The actomyosin was extracted from the ice-stored fish and the enzymatic activity of cathepsin L and trypsin-like protease in the extract was assayed. The two enzymes remained in the carp actomyosin despite intensive leaching during the extraction procedure. The activity of cathepsin L decreased slightly after 2 days of storage and remained relative constant thereafter, suggesting the enzyme was only slightly affected by the short term iced-storage. However the activity of the trypsin-like protease increased rapidly with iced-storage time, indicating that it might have been activated during the short term storage in ice.