Abstract: 　Objective To explore the invading mechanism of amebae in lamina porpria and observe the interaction between the cysteine proteinase (CP) of Entamoeba histolytica and laminin. Methods CP was identified by laminin-sepharose affinity chromatography, followed by isolation, purification and inhibitor experiment. The hydrolytic activity was measured by gelatin electrophoresis. Results Purified CP of E.histolytica showed a strong affinity with laminin. The molecular weight of CP is 27 kDa. It can be inhibited by EC-64 and exhibited a protein hydrolytic activity. Conclusion The specific affinity and hydrolytic activity of CP might play an important role in its invasion to the basement membrane of intestinal mucosa.

Key words: Entamoeba histolytica, cysteine proteinase, hydrolytic activity