The protein with endogenous α-amylase inhibitor activity was extracted and purified from wheat (Triticum aestivum) grains through 70% ammonium sulphate fractionation, ion-exchange chromatography on DEAE-Sephacel and gel-chromatography on Toyapearl HW-50. The molecular weight and isoelectric point of protein were estimated about 21 kD and 7.0 respectively. The inhibitor repressed of high pI wheat α-amylase isozymes, but had no effect on amylases of microbial and animal origin. The inhibitor also exhibited activity towards serine protease subtilisin. The inhibitor was the most active at pH 7.8 to pH 8.0 and was stable up to 90° C for 10 minutes. The protein is localized in the peripheral parts of the seed, and in the starchy endosperm.