title: New and specific nucleoside diphosphate glucose substrates for glycogenin.
abstract: Glycogenin, the autocatalytic, self-glucosylating primer for glycogen synthesis by glycogen synthase, is presumed, in vivo, to use UDP-glucose as the source of the glucose residues it adds to itself. When we tested its ability to utilize other nucleoside diphosphate glucoses, it emerged that purine nucleotides are not utilized but two pyrimidine nucleotides are used, in addition to UDP-glucose. These are CDP-glucose and TDP-glucose. CDP-glucose is utilized at 70% of the rate of UDP-glucose. While there is no evidence that CDP-glucose is a natural substrate for glycogenin, it has the advantage over UDP-glucose in that it can be used specifically to detect and assay glycogenin in the presence of glycogen synthase because CDP-glucose, unlike UDP-glucose, is not a substrate for the synthase.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, FL 33101.
authors.forename: M D
authors.initials: MD
authors.lastname: Alonso
authors.forename: E J
authors.initials: EJ
authors.lastname: Lagzdins
authors.forename: J
authors.initials: J
authors.lastname: Lomako
authors.forename: W M
authors.initials: WM
authors.lastname: Lomako
authors.forename: W J
authors.initials: WJ
authors.lastname: Whelan
mesh_terms: D005947:Glucose / Q000031:analogs & derivatives* / Q000378:metabolism; D005964:Glucosyltransferases; D006006:Glycogen Synthase / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D006023:Glycoproteins; D009702:Nucleoside Diphosphate Sugars; C073881:cytidine diphosphate-glucose; C051887:glycogenin; C100183:thymidine diphosphate sugars; D005964:Glucosyltransferases; D006006:Glycogen Synthase; D005947:Glucose