Polyacrylamide gel electrophoresis has been used to study the Ti and Sp1 seed proteins of the soybean. The Ti protein has been identified as the Kunitz soybean trypsin inhibitor or SBTI-A2 (Kunitz, 1945; Rackis et al., 1962; Singh, Wilson and Hadley, 1969). The three fonns of SBTI-A2 designated as Ti1, Ti2 and Ti3 are electrophoretically distinguishable from one another by their different Rf values of 0.79, 0.75 and 0.83 (Rf= mobility relative to the dye front in a 10% polyacrylamide gel anodic system using a pH 8.3 Tris-glycine buffer) respectively.