PURIFICATION AND PHYSICO-CHEMICAL PROPERTIES OF 11S GLOBULIN IN SOYBEAN SEEDS

11S globulin, the major storage protein of soybean seeds, was isolated to be homogeneous in ultracentrifugation, disc electrophoresis and isoelectric focusing by a comparatively simple method using gel filtration on Sephadex G-100 and G-200 columns with a good yield. The protein had the molecular weights of 309,000–322,000 by three separate methods based on different principles. Subsequently, some physico-chemical properties of the protein were determined. For example, sedimentation coefficient, isoelectric point, intrinsic viscosity and absorptivity constant were 12.2S, pH 4.64, 0.0485 dl/g and 8.04, respectively. Optical rotatory dispersion studies of the protein gave the values of a0 = —246 and b0 = —33. The contents of α-helix and β structure calculated from these parameters were estimated to be 5.2% and 34.8%, respectively.