Soybean 11S globulin polypeptides have an antigenic homology with 11S globulins from various plants.

Rabbit serum antibodies (AB) against glycinin acidic polypeptides were separated by cross exhausting, and the antibody fractions for each of the two subfamilies of glycinin subunits (A1 and A3) were obtained. The antibodies were used in the immuno blot assay with seed protein of various plant classes. Polypeptides homologous to soybean glycinin were detected. Homology with A1 polypeptide was revealed in more cases than with A3. Total seed protein preparations were subjected to centrifugation in sucrose density gradient, and the polypeptides, imunochemically related to glycinin, occurred only in fractions with sedimentation constant about 11S. The nativity of conservative antigenic determinants of 11S globulins is discussed.