Extraction and Electrophoretic Characterization of Rice Proteins

Rice proteins were extracted from brown and milled rice of five varieties: Kwanganbyeo, Daeanbyeo, Daejinbyeo, Surabyeo, Hwaseongbyeo; and their electrophoretic patterns were analyzed by SDS-PAGE. Albumin was extracted with water, globulin with 5% NaCl, prolamin with 70% ethanol, and glutelin with 0.2 M sodium borate buffer (pH 10.0) containing 0.5% SDS, 0.6% β-mercaptoethanol. The ratios of albumin : globulin : prolamin : glutelin in the brown rice were 10.8~14.1 : 12.4~16.4 : 3.6~5.3 : 68.6~72.8, and in milled rice were 4.4~5.6 : 10.6~12.0 : 3.9~5.4 : 75.7~79.8. In albumin seven major bands were observed with molecular weights ranging from 14.9~96.8 kDa, in globulin four bands with molecular weights in the range of 14.4~56.9 kDa, prolamin had only one band with a molecular weight of 14.4 kDa, and glutelin had four bands with molecular weights of 14.4~57.4 kDa. There were no differences in electrophoretic patterns between rice varieties or between brown and milled rice.