Sucrose-Uridine Diphosphate Glucosyltransferase from Jerusalem Artichoke Tubers

Purine and pyrimidine nucleotides were purchased from Pabst Laboratories, Milwaukee, and from Schwarz BioResearch, Inc., Orangeburg, New York.Crystalline hexokinase,l phosphoglucomutase, and glucose 6-phosphate dehydrogenase were obtained from Boehringer and Soehne GmbH, Mannheim, Germany.Uridine diphosphoglucose dehydrogenase, type III, was obtained from Sigma Chemical Company, St. Louis, but in later stages of work it was prepared from calf liver according to a described procedure (14).Sucrose phosphorylase was partially purified from Pseudomonas saccharophila according to Doudoroff (15).* Supported by Research Grant FG-IS-141 from the United States Department of Agriculture.1 The crystalline hexokinase samples used were found to contain an appreciable amount of phosphoglucose isomerase.W-Labeled sugars were obtained from the Radiochemical Centre, Amersham, England, and Celite and Sephadex through L. Light and Company, Colnbrook, England.Acid-washed Darco G-60 charcoal (Atlas Powder Company, New York) was washed with 0.2 M sodium citrate, pH 7.0, then with water, ethanol, and water again, and finally was dried at 60".Other substrates and materials used were analytical grade, commercially available reagents.Tris buffer was always used in the chloride form.Jerusalem artichoke tubers in the dormant condition, grown in Jerusalem by the Department of Botany of The Hebrew University, were obtained during February, March, and April 1963.Tubers which started to sprout in late April were found unsuita ble for the present studies because invertase activity appears to be present in the developing buds.Tubers were kept in the dark at 4" and for about 2 weeks were found suitable for enzymatic studies.A longer period of storage resulted in wilting and a marked decrease in the yield of enzyme activity which could be found in the extracts.