The occurrence of beta-amylase in Entamoeba histolytica.

A beta-amylase like activity isolated from a cell homogenate of Entamoeba histolytica, and separated from other glucohydrolytic activities by gel filtration and isoelectric focusing, hydrolyzed amylose, amylopectin and glycogen, yielding maltose as reaction product. From the non-reducing ends of the 4-nitrophenyl-alpha-D-glycosides of maltotriose, maltotetraose, maltopentaose and maltohexaose the enzyme removed maltose units. The pH optimum for hydrolyzing the poly- and oligosaccharides was pH 6.5, and the temperature optimum was 29 degrees C. Estimation of relative molecular mass by gel filtration on Sephadex G 75 gave values around Mr = 32 000. The isoelectric point was found to be 5.7.