Cereal Chem 45:192 - 200.  |  VIEW ARTICLE
Starch-Gel Electrophoresis of Soybean Globulins.

G. Puski and P. Melnychyn. Copyright 1968 by the American Association of Cereal Chemists, Inc. 

Soybean globulins, isolated fractions (7S, 11S, and cold-insoluble fraction), and alkylated derivatives of soybean globulins were examined by starch-gel electrophoresis in alkaline and acidic buffer systems. The alkaline gel was made with 0.0825M tris-chloride solution, pH 8.7, and contained 5M urea and 0.1M mercaptoethanol. A 0.05 tris-0.35M glycine-3M urea 0.05M mercaptoethanol buffer, pH 8.4, was used as the bridge solution. The acid gel was prepared in 1N acetic acid-5M urea buffer, pH 3.5, and 1N acetic acid was used as the bridge solution. Protein samples were dissolved in the tris-glycine or acetate buffers which contained 6M urea and 0.1M mercaptoethanol. Soybean globulins manifested 14 and 15 readily discernible bands in the alkaline and acidic media, respectively, as well as some poorly resolved bands. The electropherograms were unaffected by phytates. Electrophoretically, 7S and 11S fractions were heterogeneous and were not comprised of the same proteins. The cold-insoluble fraction had all the 11S components, but also contained other proteins. At least three constituents of the 11S and CI fraction possess strong basic character, since they migrated toward the cathode at pH 8.7. Reaction of soybean globulins with iodoacetate, N-ethylmaleimide, and acrylonitrile was enhanced by the presence of urea. Derivatives did not give identical electrophoretic patterns.