The Occurrence of Adenosine Diphosphate Glucose: Glycogen Transglucosylase in Bacteria.

There are many reports of glycogen accumulation in various species of bacteria (58). However, the enzymatic synthesis of glycogen in bacteria has received little attention. Madsen has reported the presence of a UDP-glucose:glycogen transferase in Agrobacterium tumefaciens (A6) (9). Recently the occurrence of an ADP-glucose : glycogen transglucosylase in cell-free extracts of Arthrobacter was reported (10). This enzyme was specific for the adenine sugar nucleotide; UDPglucose, TDP-glucose, GDP-glucose, CDP-glucose, and IDPglucose could not replace ADP-glucose as the glucosyl donor. Because of the specificity of the Arthrobacter glycogen transglucosylase, cell-free extracts of other bacteria were examined. Aerobacter aerogenes were grown on tryptone-glucose media (6); Agrobacterium tumefaciens were grown according to Madsen (11); Arthrobacter species NRRL B1973 were grown on glucosesynthetic media (12); Escherichia coli B were grown according to Holme and Palmistierna (5); Rhodospirillum rubrum were grown according to Cohen-Bazire, Sistrom, and Stanier (13), and dried cells of Micrococcus lysodeiktikus were obtained from the Sigma Chemical Company. After the cells were harvested, they were suspended in 4 volumes of 0.05 M Tris-HCl buffer, pH 7.9, containing 0.005 M reduced glutathione and 0.01 M MgC12. They then were ruptured in a French press at 20,000 p.s.i.r Cell-free extracts were obtained by centrifugation at 1,200 x g for 15 minutes. The cell-free extracts were then fractionated by centrifugation to give a 30,000 x g particulate fraction, a 105,000 x g particulate fraction, and a 105,000 x g supernatant fluid. The particulate fractions were washed once with the above buffer and then suspended in the same buffer. Table I shows that of the three sugar nucleotides tested, ADP-glucose was by far the best glucosyl donor. The omission of glycogen from the reaction mixture during the incubation period or the addition of 15 pg of cu-amylase to the reaction mixture decreased the 14C-glucose transfer to glycogen from