Proteinase in Pacific Whiting Surimi Wash Water: Identification and Characterization

Abstract

ABSTRACTA proteinase in Pacific whiting surimi wash water (SWW) was characterized to be cathepsin L based on molecular mass (Mr), substrate specificity, and SDS‐substrate gel electrophoresis. The proteinase was highly active on Z‐Phe‐Arg‐NMec, and the native Mr was 27,400 based on size exclusion (SEC)‐HPLC. Acidification of the SEC‐HPLC fractions showed a two‐fold increase in activity on Z‐Phe‐Arg‐NMec. SWW proteolytic activity was found at Mr 54,200 on SDS‐substrate gel. However, acidification shifted the activity zone to Mr 39,500 corresponding to cathepsin L. No evidence of activity by calpain or cathepsin B or H was found in Pacific whiting SWW.