Studies on the biosynthesis of starch: I. Isolation and properties of the soluble adenosine diphosphate glucose: Starch glucosyltransferase of Solanum tuberosum

Abstract

A soluble glucan synthetase (starch synthetase) has been isolated from potato tubers. This enzyme catalyzes the transfer of glucose from adenosine diphosphate glucose, deoxyadenosine diphosphate glucose, and to a lesser extent, from β-adenosine diphosphate glucose to phytoglycogen, amylopectin, and malto-oligosaccharides. β-Limit dextrins, dextran, and isomalto-oligosaccharides were inactive as primers. The freshly prepared enzyme also catalyzes the transfer of glucose from the sugar nucleotide to the intact starch granules, but this activity disappears with storage. The properties of the enzyme which acts on the soluble primers were studied.