Isolation and Identification of a New Type of β-Conglycinin in Soybean Globulins

A new type of β-conglycinin was found in precipitates of a crude glycinin fraction at pH 6.4 and low ionic strength. The protein was purified by ammonium sulfate fractionation, Con A-Sepharose 4B affinity chromatography and ion-exchange chromatography on DEAE-Sepharose CL-6B. The purity check and identification of the protein were performed by gel electrophoresis, gel filtration, N-terminal amino acid analysis, immunochemical analysis and ultra-centrifugal analysis. This protein (designated as B0-conglycinin) was composed of three identical subunits which were identical with the β-subunit in β-conglycinins at 0.5 ionic strength, but differed from the other β-conglycinins in that B0-conglycinin formed an insoluble aggregate at ionic strengths less than 0.2.