Abstract Disc electrophoresis of soybean storage globulins indicated four major components with molecular weights in excess of 300 000. Treatment with sodium dodecylsulphate (SDS) resulted in an increased number of components with an overall lower MW spectrum. Polypeptides, produced by the performic acid oxidation of the globulins, gave 8 bands when solubilized in 2.5 % NACl, but only 4 when solubilized in 0. 1 % SDS. Reasons for this reduction of subunit number are suggested. Preparative fractionation of the SDS-polypeptides on Sephadex G75 columns gave the same number of components, having a similar distribution and proportion.