Separation and characterization of four different amylases of Entamoeba histolytica. I. Purification and properties

Cell homogenate of Entamoeba histolytica trophozoites was investigated for amylolytic activity against various biogenic and synthetic substrates. After gel filtration of the cell homogenate on Sephadex G-150, six partly separated amylases (I to VI) differing in their substrate specificities were detected using maltose, amylose, amylopectin, 4-nitrophenyl alpha-glucoside and 4-nitrophenyl alpha-maltotetraoside. All enzymes are able to degrade amylose, amylopectin, glycogen and biogenic malto-oligosaccharides. Since amylase I and II, which accepted maltose as substrate, were found in fresh (cell-free) medium containing calf serum, the possibility cannot be excluded that these enzymes originate from the medium and therefore are not associated with E. histolytica trophozoites. Amylases III to VI, which were not found in fresh medium, were further purified by isoelectric focusing and chromatographic procedures using DEAE, CM ion exchange materials and Con A Sepharose 4B. pH, temperature optima and relative molecular masses were determined.