グアー豆タンパク質の分画と大豆タンパク質との性質の比較

Abstract

The proteins of the guar (Cyamopsis tetragonoloba) meal left after the extraction of gum were exam-ined with reference to soy bean proteins. 1) The total protein of the guar meal was obtained by extracting the meal with a 2% SDS solution, and analyzed by SDS-polyacrylamide gel electrophoresis. The molecular weights of guar meal proteins ranged from 8 kDa to 74 kDa and those of soy bean proteins obtained by the same method 15 kDa to 96 kDa. 2) The guar meal was treated successively with five different solvents, i.e, water, 1 M NaCI, 70% ethanol, 0.025% NaOH, and 1% SDS. The extracted protein fraction in each treatment was analyzed by SDS-polyacrylamide gel electrophoresis and the amount of the proteins was quantified. Most proteins were recovered in the water fraction and the NaCI fraction with yields of 29% and 43% of the total protein, respectively. The water fraction contains proteins with lower molecular weights (8 kDa to 12 kDa) whereas the NaCI fraction those with higher molecular weights (20 kDa to 74 kDa). 3) The amino acid compositions of both the water and NaCI fractions were characterized by high contents of Ser, Glu, and Gly. The amino acid scores of the water and NaCI fractions were calculated to be 48 and 50, respectively, which were comparable with those of ordinary grains and lower than those of soy bean proteins.