Cereal Chem 57:155 - 158.  |  VIEW ARTICLE
Analysis of Soy Protein Disc Gel Electropherograms.

R. L. Anderson. Copyright 1980 by the American Association of Cereal Chemists, Inc. 

Water-extractable, acid-precipitable, and whey proteins from soybeans were examined by disc gel electrophoresis in pH 8.9 tris-glycine buffer at gel concentrations (%T) ranging from 4 to 13. Densitometer tracings of the stained gels were used to construct Ferguson plots (log relative protein mobility [RM] vs %T), thereby yielding relative free mobilities (Yo) and retardation coefficients (KR). Among gels of various %T, 28 protein bands were distinguished in the water-extractable fraction; plots were made for 18. On a single 8.5%T gel, 20 water-extracted proteins were discernible. Acid-precipitable soy proteins differed only slightly from those that were water-extractable. Ferguson plots for these fractions could be conveniently placed into seven groups based upon Yo. The whey proteins produced five major and 11 minor bands. Twelve of the 16 whey bands produced data for Ferguson plots, which comprised three groups on the basis of KR. The KR and Yo for three of the major whey bands matched those determined for water-extractable soy protein components. The remaining major whey proteins appeared to be charge isomers that were obscured by other proteins in the water-extractable fraction. A band having the KR and Yo of soybean trypsin inhibitor was found in all three fractions. The approach used here extends the usefulness of disc gel electrophoresis for comparing various soy protein preparations and for interpreting the effects of different treatments given soy protein.