Protease activity in brook trout (Salvelinus fontinalis) follicle walls demonstrated by substrate-polyacrylamide gel electrophoresis

Proteolytic activity was demonstrated in the follicle wall surrounding oocytes of brook trout (Salvelinus fontinalis) by an assay system that incorporated protein substrates into sodium dodecyl sulfate-polyacrylamide gel electrophoresis (substrate-SDS-PAGE). At least six proteolytic enzymes (78, 70, 67, 59, 22 and 20 kDa) were present when follicle wall extracts were electrophoresed and incubated in gels containing gelatin. Of these six enzymes, only two enzymes (20 and 22 kDa) were present when follicle wall extracts were resolved and incubated in gels containing casein. The activities of the 78 and 70 kDa enzymes were completely inhibited with metallo- and collagenolytic protease inhibitors and partially inhibited with serine protease inhibitors. The activities of the 67 and 59 kDa enzymes were completely blocked with metallo- and collagenolytic protease inhibitors. The activities of the 22 and 20 kDa enzymes were only slightly decreased with a serine protease inhibitor.