Physical characterization of α-amylase inhibitors from wheat

Abstract

Six albumins from the kernels of hexaploid wheat, designated 0.19, 0.28, 0.32, 0.35, 0.39 and 0.48 according to their electrophoretic mobilities, were characterized according to their molecular weights, circular dichroism spectra, fluorescence spectra, amino acid compositions, and their specificities in inhibiting α-amylases from human saliva, chick pancreas, yellow mealworm, Aspergillus oryzae, and Bacillus subtilis. The 0.19 and 0.28 proteins have been related to other proteins described in the recent literature for which, however, characterization had been inadequate for the evaluation of possible identities. The 0.28, 0.32, 0.35, 0.39 and 0.48 proteins have been shown to belong to a family of closely related proteins. For example, they had identical circular dichroism spectra in the near ultraviolet that differed considerably from that of 0.19 protein, and they were all strong inhibitors of the α-amylase from the yellow mealworm ( Tenebrio molitor L.) but were inactive against several other α-amylases, whereas the 0.19 protein was a strong inhibitor of α-amylases from human saliva and chick pancreas as well as that from the yellow mealworm.