Glycogenin 1 (GYG1)

Glycogenin is a self-glucosylating protein involved in the initiation reactions of glycogen synthesis. During initiation, the covalent attachment of a glucose residue to glycogenin is followed by elongation to form an oligosaccharide chain. Recombinant mammalian glycogenin was enzymatically active and capable of self-glucosylation. After incubation with UDP-glucose, the recombinant protein was able to serve as a substrate for glycogen synthase, leading to the production of high M(r) polysaccharide.The predicted 333-amino acid human protein shares 93% identity with rabbit muscle glycogenin. Northern blot analysis revealed that the 2.4-kb glycogenin mRNA was expressed prominently in human skeletal muscle and heart, and to a lesser extent in several other tissues.