N-terminal sequence of soybean beta-amylase.

The blocked N-terminus and N-terminal sequence of soybean beta-amylase were determined by analyzing the acidic peptides derived on peptic digestion of the enzyme. The acidic peptides were separated from the digest on a Dowex 50 X 2 column and purified by reversed phase-high performance liquid chromatography (RP-HPLC). The major acidic peptide, Pep-4, was a heptapeptide with a molecular weight of 766. Forty-eight hundredths mol acetyl group and 0.61 mol acetyl-Ala per mol of Pep-4 were detected on RP-HPLC analysis. The N-terminal 9 amino acid sequence of soybean beta-amylase was deduced to be acetyl-Ala-Thr-Ser-Asp-Ser-Asn-Met-(Gly-Leu) from the results of sequence analysis of Pep-4 and amino acid analysis of other acidic peptides.