Carbohydrate Metabolism in Streptomyces hygroscopicus

An enzyme system has been isolated from Streptomyces hygroscopicus that catalyzes the transfer of glucose from guanosine diphosphate d-glucose-14C to glucose 6-phosphate to form trehalose phosphate. The reaction appears to be specific for GDP-glucose; relatively little activity was found in trehalose phosphate when other 14C-glucose nucleotides were used in place of GDP-d-glucose. Glucose-6-P, mannose-6-P, and fructose-6-P all served as acceptors because of the presence of phosphohexose isomerase, but other phosphorylated sugars were inactive. The product formed in the presence of GDP-d-glucose-14C and glucose-6-P was characterized as trehalose phosphate by chemical, enzymatic, and chromatographic methods.