The complete amino acid sequence of the A3 subunit of the glycinin seed storage protein of the soybean (Glycine max (L.) Merrill).

The amino acid sequence of the A3 subunit, an acidic subunit of the glycinin seed storage protein of the soybean (Glycine max (L.) Merrill), has been determined by sequence analysis of the peptides obtained by cyanogen bromide cleavage followed by enzymatic digestion and partial acid hydrolysis. The A3 subunit is composed of 410 amino acids (Mr approximately 46,000). It has been confirmed that there are conserved, repeated domains within the subunit. A comparison of the NH2-terminal sequence of the A4 subunit with the sequence of the A3 subunit reveals that a sequence highly homologous to the NH2-terminal sequence of the A4 subunit exists in internal regions of the A3 subunit. This suggests that the genes coding for the acidic subunits of glycinin are strongly related, and have the same evolutionary origin.