A soybean G2 glycinin allergen - 1. Identification and characterization

Background: Multiple allergens have been documented in soybean extracts. Ig E from individuals allergic to soybeans, but not to peanut, was shown by im munoblot analysis to bind to proteins with a molecular weight of approximat ely 21 kD. These findings suggested that unique proteins in soybeans might be responsible for soybean allergic reactivity. The objective of the presen t study was to identify unique proteins in soybean extracts that bind to sp ecific IgE from soybean-sensitive individuals, and to characterize the alle rgen using physicochemical methods and IgE binding. Methods: Two-dimensiona l and preparative SDS-PAGE/IgE immunoblot analysis was used to identify a 2 2-kD soybean-specific allergen from crude soybean extracts. N-terminal sequ ence analysis was used to determine the identification of the protein bindi ng IgE from soybean-sensitive individuals. Results: IgE immunoblot and amin o acid sequence analysis identified the 22-kD protein as a member of the G2 glycinin soybean protein family. Further investigation revealed that the I gEs reacted with basic chains from each member of the glycinin family of so ybean storage proteins. Conclusions: Each of the subunits from glycinin, th e storage protein that is the most prevalent component of soybean, are majo r allergens. Copyright (C) 2000 S. Karger AG, Basel.