Abstract
Kidney beans contain a water-soluble substance which strongly inhibits the larval growth of azuki bean weevil. The substance has been purified by fractionation methods involving dialysis, precipitation with ammonium sulfate, and chromatographies with DEAE-Sephacel and Con A-Sepharose. The inhibitory activity was bioassyed using the artificial beans incorporating the fractionated materials after lyophilizing into the azuki bean meal. The purified substance, which is one of glycoproteins having the molecular weight of about 100, 000, showed inhibitory activity on α-amylase. When the α-amylase inhibitor was incorporated at 0.2-0.5% into the artificial beans, the larvae of the weevil could not develop by feeding them and died. The results obtained here show that the α-amylase inhibitor is responsible for the protection of kidney beans against the attack of azuki bean weevil.
