Abstract
The relationship between the amylases in rice and the mechanism of degradation of starch in cooking of rice remains to be clarified. In this paper, α-amylase [EC 3.2.1.1] I and II were purified from polished rice granules by ammonium sulfate and acetone fractionation, DEAE-cellulose column and Sephadex G-75 gel chromatographies. The molecular weights of the purified a-amylase I and II were estimated to be 46, 000 and 61, 000 by Sephadex G-75 gel chromatography and their Km values for soluble starch were 3.5 and 2.3 mg/ml, respectively. And α-amylase II was more stable than a-amylase I against temperature.
