Recovery and Characterization of a Serine Collagenolytic Extract from Snow Crab (<Emphasis Type="Italic">Chionoecetes opilio</Emphasis>) By-products

Sequential acidic precipitation followed by a single chromatographic step (gel filtration) allowed the recovery of a collagenolytic fraction containing several proteases from by-products of snow crab (Chionoecetes opilio). The partial purification was particularly efficient to recover tryptic (purification fold = 1,352.5; yield = 110%) but also chymotryptic, elastolytic, and collagenolytic activities. A temperature of 40 °C and pH 8.0–8.5 were optimal for enzyme activity, which was stable for 2 h under these conditions. Calcium was not required for stability and thus activity. The isoelectric points of the protein components ranged from 3.7 to 4.6. Zymography revealed 29 and 48 kDa major components and others from 22 to 56 kDa. Enzymes were inhibited by PMSF and TLCK but were insensitive to TPCK. In view of these properties, the proteases likely belong to the serine collagenase group. Inhibition by EDTA could be due to a mechanism other than Ca²⁺ chelation. Using a food system (ground fish), the fraction was more proteolytic than a commercial bacterial protease, suggesting potential applications in enzymatic hydrolysis processes.