Specificity of uridine diphosphate glucose-glycogen glucosyltransferase

New and specific nucleoside diphosphate glucose substrates for glycogenin

“…We do not therefore suggest that either of these glucose donors is a native substrate for mammalian glycogenin. The importance of the finding that CDP-glucose is an effective alternative to UDPglucose is because CDP-glucose is not utilized by muscle glycogen synthase [20]. (TDP-glucose is used by synthase, at 5% of the rate of UDP-glucose [21].)…”

Synthesis of branched polysaccharides with tunable degree of branching

“…2). It was already reported in literature that muscle phosphorylases act more on branched acceptors than on linear ones (Cori & Cori, 1936;Goldemberg, 1962) which explains this higher conversion for the tandem polymerization. The reaction mixture containing only Dg GBE was used as a blank reaction showing that DgGBE alone does not produce any linear or Fig.…”

“…This is due to GPbs affinity towards branched polysaccharides (Goldemberg, 1962;Cori & Cori, 1936). The linear polymerization catalyzed by GPb is faster than the branching catalyzed by Dg GBE which means that time is the best mean to tune the degree of polymerization.…”

Allosteric Regulation of Enzyme Activity

“…It will be of interest to determine if the differences in effector specificities of the ADP-pyrophosphorylases from the two groups of organisms are correlated with differences in their pathways of carbohydrate metabolism. Noteworthy is the fact that although UDP-glucose and ADP-glucose will serve as glucosyl donors far the biosynthesis of glycogen in a number of organisms, the former compound is the preferred donor in animals (259,260) whereas the latter is the preferred donor in some bacteria (106,261) and plants (261)(262)(263)(264). Oliver (265) showed that the UDP-glucose pyrophosphorylase from rat liver and guinea pig brain is competitively inhibited by galactose-l-P and is noncompetitively inhibited by orthophosphate.…”