Abstract:

A preparation of starch grains from potato tubers was found to catalyze the incorporation of d-glucosyl residues from adenosine diphosphate d-glucose or from uridine diphosphate d-glucose into starch. The newly synthesized linkages were of the α-1,4 configuration. Oligosaccharides of the maltose series also served as d-glucosyl acceptors. d-Glucose was transferred to either acceptor at a greater rate from adenosine diphosphate d-glucose than from the uridine diphosphate derivative. Starch grains from potato sprouts and from seeds of wrinkled peas, red and white corn, and waxy maize were also shown to catalyze the incorporation of glucosyl units into starch. In each case, adenosine (or dcoxyadenosine) diphosphate d-glucose was a better glucosyl donor than uridine diphosphate d-glucose. Starch grains from seeds of waxy maize catalyzed the synthesis of starch at a relatively low rate; however, the formation of maltooligosaccharides was much more rapid. Transfer of glucose from the sugar nucleotides to starch and to oligosaccharides was markedly inhibited by phenols and phenolic glucosides. © 1963.