Comparative Electrophoretic Studies of Trypsin Inhibitors in Seed of the Genus Glycine

Seed protein extracts from collections representing seven wild species of Glycine were analyzed for trypsin inhibitor bands by polyacrylamide gel electrophoresis. The presence and activity of trypsin inhibitors in bands were determined by the standard trypsin inhibitor assay method and by a new procedure which we name the "trypsin inhibitor-trypsin complexing" method. Trypsin inhibitor activity was found in seed protein of all species of Glycine tested. The species in the subgenus Soja: G. soja, G. gracilis, and the soybean G. max were indistinguishable when analyzed electrophoretically. There was an unusual amount of variation in trypsin inhibitor banding patterns among accessions in the species G. wightii; however, they could be separated into two basic types. In the subgenus Glycine, the species G. clandestina, G. tabacina, and G. tomentella were very similar, while the one accession of G. falcata appeared completely different.