A dimeric inhibitor or insect α‐amylase from barley

A cDNA clone, designated pUP-44, whose longest open reading frame codes for a protein that is homologous to the wheat alpha-amylase inhibitors, has been isolated from a library obtained from developing barley endosperm. The deduced sequence for the mature protein, which is 122 residues long, is preceded by a sequence of 30 residues which has the typical features of a signal peptide. A closely corresponding protein, designated BDAI-1, has been isolated from mature endosperm. BDAI-1 behaves as a dimer and inhibits the alpha-amylase from the insect Tenebrio molitor at concentrations that have no effect on salivary or pancreatic alpha-amylases.