Abstract: 　Objective To identify the proteinases in intestinal contents of Schistosoma japonicum (S.japonicum) adult worms. Methods Proteinases were fractionated through gelatin SDS PAGE, and gelatin was degraded by proteinases when the gel was incubated in buffer with optimal pH. Metalloproteinase which degrades gelatin was identified by incubating gel in optional buffer containing different enzyme inhibitors. Metalloproteinase was isolated through SDS PAGE. Results A metalloproteinase was identified in intestinal contents of S.japonicum adult worms. The optimal pH of metalloproteinase is pH 7-9. The activity of the metalloproteinase was inhibited by EDTA. The metalloproteinase showed enzymatic activity after being fractionated through SDS PAGE and weakly reacted with sera of rabbits infected with S.japonicum . Conclusion A metalloproteinase is present in intestinal contents of S.japonicum adult worms.

Key words: Schistosoma japonicum, adult worm, intestinal contents, gelatin, electrophoresis, inhibitor, metalloproteinase