アミラーゼの基質としてのエルシナンとその酵素分解生成物'

抄録

Elsinan, a new α-D-glucan consisting of maltotriose and a small amount of maltotetraose units joined by α-(1→3)-D-glucosidic linkages, was degraded by several a-amylases, e, g., salivary, hog pancreas, Aspergillus oryzae, and Bacillus subtilis saccharif ying a-amylases. The action of human salivary α-amylase on elsinan resulted in release of O-α-D-glucopyranosyl-(13)-O-α-D-glucopyranosyl-(14)-D-glucopyranose as a major product together with maltose and O-α-D-glucopyranosyl-(14)-O-α-D-glucopyranosyl-(13)-O-α-D-glucopyranosyl-(14)-Dglucopyranose. It is proposed that α-D-glucosidic linkage involving the hydroxyl group at the C-4 position of glucose unit whose C-1 position is joined to the adjacent α-(1→3)-linked glucose unit is preferentially attacked by human salivary α-amylase. A. oryzae a-amylase hydrolyzed elsinan to form a tetrasaccharide, which was characterised as O-α-D-glucopyranosyl-(1→3)-O-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4) -D-glucopyranose, and a heptasaccharide. B. subtilis liquefying a-amylase, a thermostable bacterial aamylase, β-amylase, and glucoamylase are not able to hydrolyze elsinan.