SEMIQUANTITATIVE PURIFICATION AND ASSESSMENT OF PURITY OF 3 SOYBEAN PROTEINS, GLYCININ, BETA-CONGLYCININ AND ALPHA-CONGLYCININ, BY SDS-PAGEELECTROPHORESIS, DENSITOMETRY AND IMMUNOBLOTTING

Semi-quantitative purification of the three most antigenic proteins of soybean seeds, e.g., glycinin, beta-conglycinin and alpha-conglycinin , was studied. In first step,fractions were pre-purified by successive precipitations of respective proteins at an appropriate isoelectric p oint and/or ionic strength. Then, glycinin, beta-conglycinin and alpha -conglycinin fractions were isolated by gel filtration. The procedure was carried out on a semi-preparative scale, and used to purify about 2 g glycinin and 1 g each of beta-conglycinin and alpha-conglycinin, f rom 1 kg of defatted soybean flour. purity of glycinin, beta-conglycin in and alpha-conglycinin fractions was checked by sodium dodecylsulpha te polyacrylamide gel electrophoresis and immunoblots. Contaminants de tected in both glycinin (9%) and alpha-conglycinin (4%) fractions, but the beta-conglycinin obtained was pure.