Activity Staining of Pacific Whiting ( Merluccius products ) Protease

An activity staining method using SDS‐substrate gel was used to determine Pacific whiting proteolytic activity. The most active protease band was resolved at an apparent M, of 39,500 corresponding to the activity of cathepsin L. The activity was more pronounced for ocean‐caught Pacific whiting than Puget Sound Pacific whiting or ocean‐caught arrowtooth flounder. Gel electrophoresis activity staining of proteolytic enzymes in Pacific whiting was not as sensitive as the TCA‐azocasein assay but provided information on the molecular properties of the enzyme and a semi‐quantitative estimation of activity.