Cereal Chem 63:493-496   |  VIEW ARTICLE
Quantitative Analysis of Soybean Proteins by Densitometry on Gel Electrophoresis.

K. Sato, T. Yamagishi, and F. Yamauchi. Copyright 1986 by the American Association of Cereal Chemists, Inc. 

Quantitative analyses of soybean globulins were made by densitometry in a sodium dodecyl sulfate (SDS)- polyacrylamide slab gel using lysozyme as an internal standard protein and Coomassie Brilliant Blue as a staining reagent. The slopes of standard curves for soybean globulins showed a considerable difference, depending on their proteins. The densitometric intensity for the 7S globulins of gamma-conglycinin, basic- 7S globulin, and beta-conglycinin was higher than for glycinin and Kunitz trypsin inhibitor. Proteins extracted with both water and 0.5M sodium chloride contained glycinin (36.5%), beta-conglycinin (27.8%), gamma-conglycinin (6.2%), Kunitz trypsin inhibitor (2.9%), basic-7S globulin (3.0%), and other proteins (23.6%) that included whey protein. The relative concentrations of the major components (glycinin and beta-conglycinin) were evaluated to accuracies better than +/-15%, and other minor components were evaluated to +/-20%.