The identity of α-amylase inhibitors from Toramame (Phaseolus vulgaris L.) and Uzuramame(Phaseolus vulgaris L.)

The identity of α-amylase inhibitors (TAI and UAI) from Toramame (Phaseolus vulgaris L.) and Uzuramame (Phaseolus vulgaris L.) was examined by comparing peptide maps and sugar chain compositions of both inhibitors. The amino acid compositions of α and β subunits of UAI were very similar to those of TAI, respectively. The peptide maps in the Staphylococcus protease digestion of α-subunit and in the lysylendopeptidase digestion of β-subunit of UAI were identical with those of TAI, respectively. These results showed that both inhibitors had the same amino acid sequence. The comparison of sugar chain compositions of both inhibitors suggested that the major glycoforms of UAI and TAI were the same and even glycoform compositions of UAI and TAI were very similar