The primary structures of the A4 and A5 subunits are highly homologous to that of the A3 subunit in the glycinin seed storage protein of soybean

The A5 subunit of the glycinin seed storage protein of soybean was purified by ion‐exchange chromatography followed by preparative SDS‐gel electrophoresis and the complete amino acid sequence was determined. The A5 subunit is composed of 97 amino acids which correspond to an M r of ~10600. Approx. 86% of the sequence of the A5 subunit was found to be identical to that of the NH2‐terminal region of the A3 subunit of the glycinin determined previously. Also, the A4 subunit of the glycinin was purified and the partial sequence was determined. The sequence of the A4 subunit was estimated to be highly homologous to that of the COOH‐terminal region of the A3 subunit.