Purification and Characterization of α-glucosidase from Rice Bran and Production of Ethyl-α-D-glucoside

Abstract

　In this study, α-glucosidase from rice bran was purified by chromatography and electrophoresis. This enzyme has a molecular weight of 310 kDa and consists of 4 subunits with a molecular weight of 76 kDa or 36 kDa. The N-terminal amino acid sequence of the 76-kDa protein was found to be similar to that previously reported for a rice glycosidase. However, the molecular weight of the enzyme differed from that reported for any rice glycosidase. The enzymatic properties of this enzyme were almost similar to those of most rice α-glucosidases. However, 2 properties, that is, the pH activity and thermostability, were a little different from those reported for polished rice. This enzyme was stable in ethanol up to a concentration of 10% ethanol. In addition, its activity in ethanol did not decrease up to a concentration of 20% ethanol. Ethyl-α-D-glucoside was optimally produced at pH4.0 and 40°C.

　These results show that α-glucosidase from rice bran can be used in the production of ethyl-α-D-glucoside.