Abstract
Guanosine diphosphate d-glucose:d-glucose-6-phosphate 1-glucosyl-transferase was purified approximately 100-fold from extracts of Streptomyces hygroscopicus. The purified enzyme catalyzed the transfer of glucose from guanosine diphosphate-d-glucose to glucose-6-phosphate to form trehalose phosphate and guanosine diphosphate. The enzyme was specific for these two substrates and was stimulated by the addition of magnesium ions. The product was characterized as alpha-alpha-trehalose-6-phosphate by its physical and chemical properties. The enzyme was present in a large number of Streptomyces species, suggesting that this group of organisms synthesized trehalose phosphate in a unique manner. This enzyme was not detected in fungi, since these organisms utilized uridine diphosphate-d-glucose as the glucosyl donor.