Abstract

Beta amylase has been partially purified from fresh potato homogenate, by acetate buffer extraction, dialysis, ammonium sulfate fractionation, chromatography on Sephadex G75 and on CM-cellulose. After dialysis it appeared that some inhibitor was removed, since total activity increased 2.2 folds. This preparation was found to be contaminated with maltase. Approximate molecular weight calculated by Sephadex G150 was 122,000. The optimum pH was 5.1-5.5 and the optimum temperature 55°C. Activation energy calculated from 26°-42° was 6,700 cal., and the Km 4.35x10^-3 g/ml for modified soluble starch.