Localization and identification of denatured antigenic sites of glycinin A3 subunit after using two processing technologies.

Glycinin is an important allergen in soybeans. In this study, molecular cloning and recombinant phage construction were performed to explore the antigenic sites of the glycinin A3 subunit that were denatured during processing. Next, the A-1-a fragment was located as the denatured antigenic sites by indirect ELISA. The combined UHP heat treatment showed better denaturation of this subunit than the single heat treatment assay. In addition, identification of the synthetic peptide showed that the A-1-a fragment was an amino acid sequence containing a conformational and linear IgE site, in which the first synthetic peptide (P1) being both an antigenic and allergenic site. The results of alanine-scanning showed that the key amino acids affecting antigenicity and allergenicity of A3 subunit were S, K, E, L and N. Our results could provide the basis for further development of more efficient methods to reduce the allergenicity of soybeans.