Relationship between the accumulation of starch and alpha-glucosidase in rice endosperm
2003
Iwata, H. (National Research Inst. of Brewing, Tokyo (Japan)) | Isogai, A. | Utsunomiya, H. | Itani, T. | Nishio, N.
To examine the relationship between a-glucosidase and the accumulation of starch in developing rice endosperm, we measured the activities of a-glucosidase, a-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. a-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 a-glucosidase was the same as that of GBSS and pullulanase. Moreover, the purified a-glucosidase from Yamadanishiki reacted with the raw starch treated with alkali solution and produced glucose. Through these results, it can be speculated that a-glucosidase has some relationship with starch accumulation in developing rice grains.
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