Effect of an α-amylase inhibitor from barley kernels on the formation of products during the hydrolysis of amylose and starch granules by α-amylase II from malted barley

Abstract

High performance thin layer chromatography was used to analyze the products formed during degradation of amylose and starch granules by α-amylase II from malted barley in the presence and absence of an α-amylase inhibitor from barley kernels. A 40-fold molar excess of inhibitor reduced significantly the rate of α-amylolysis of amylose, but the composition of the dextrin mixture formed was not altered by the inhibitor. Significant inhibition of starch granule hydrolysis by α-amylase II was obtained in the presence of a 6-fold molar excess of inhibitor over enzyme. The composition of the low molecular weight products obtained during α-amylolysis of starch granules appeared to be slightly altered by the inhibitor. It appears unlikely that the inhibitor decreases the rate of starch granule hydrolysis by preventing adsorption of α-amylase II to the starch granules.