The Fine Structure of Glycogen from Type IV Glycogen‐Storage Disease

Abstract

The structure of glycogen isolated from a male child suffering from type IV glycogenosis (amylopectinosis) has been examined. It is confirmed that the polysaccharide is superficially similar to plant amylopectin. However, a more searching analysis involving the examination and comparison of the pullulanase‐debranched polysaccharides, revealed marked differences between the profiles of unit chains that make up the macromolecules. The type IV glycogen contains a significant proportion of short branches. The occurrence of these branches is consistent with a recent hypothesis advanced to explain why a branched polysaccharide should be synthesized in the absence of branching enzyme, this being the enzyme deletion that characterizes this type of glycogenosis.