Abstract
To examine the relationship between α-glucosidase and the accumulation of starch in developing rice endosperm, we measured the activities of α-glucosidase, α-amylase, granule bound starch synthase (GBSS), and pullulanase, as well as the a content of amylose and amylopectin in Oryza sativa cv. Nipponbare (ordinary variety) and Yamadanishiki (for a sake making variety) after their flowering. α-Glucosidase activity showed a positive correlation with fresh weight, GBSS activity, and amylose content. From the analytical results of the enzyme contents in several grades of polished rice, the distributionof α-glucosidase was the same as that of GBSS and pullulanase. Moreover, the purified α-glucosidase from Yamadanishiki reacted with the raw starch treated with alkali solution and produced glucose. Through these results, it can be speculated that α-glucosidase has some relationship with starch accumulation in developing rice grains.
