Enzyme on amylose

Figure 4-19 Schematic Representation of the Action of Starch-Degrading Enzymes. (A) Amylose and amylopectin, (B) action of a-amylase on amylose and amylopectin, (C) action of a debranching enzyme on amylose and amylopectin, (D) action of amyloglucosidase and debranching enzyme on amylose and amylopectin. Source Reprinted from H.S. Olsen, Enzymic Production of Glucose Syrups, in Handbook of Starch Hydrolysis Products and Their Derivatives, M.W. Kearsley and S.Z. Dziedzic, eds., p. 36, 1995, Aspen Publishers, Inc.

However, evidence in favor of a true structural feature that resists the action of fcefa-amylase has come from studies of the action of debranching enzymes on amylose and its hefa-limit dextrin. Thus, by treatment with yeast isoamylase, the befa-amylolysis limit of a sample of amylose was increased from 76 to 90 , and that of amylose 6e a-limit dextrin from 6 to 77 . Treatment of amylose with pullulanase also increases the conversion of the substrate into maltose by befa-amylase to an almost quantitative value. " On the basis of these results, the anomalous linkages in amylose that resist beto-amylase action are considered to be a very small proportion of (l->6)-a-D-glucosidic linkages. 

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