Glycogen, a branched polymer of glucose, is a storage molecule whose accumulation is under rigorous control in many cells. In Saccharomyces cerevisiae, glycogen biosynthesis involves three processes: nucleation, elongation, and branching (also known as ramification). The formation of glycogen begins when either Glg1p or Glg2p uses UDP-glucose to self-glucosylate to produce a short alpha (1,4)-glucosyl chain covalently attached to one of their internal tyrosine residues. After the self-glucosylation of Glg1p or Glg2p, glycogen synthase is able to extend the linear alpha (1,4)-glucosyl chains of glycogen by catalyzing the formation of alpha (1,4)-glucosidic bonds from UDP- glucose at the non-reducing ends. Branches can be added into the glycogen molecule by Glc3p, which is the glycogen branching enzyme (EC:2.4.1.18) in S. cerevisiae.
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afc
a2e
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R = a glycogenin
R = a glycogenin
glycogen biosynthetic pathway
PW:0000532
Pathway Ontology
glucose utilization pathway
PW:0000555
Pathway Ontology
glucose conversion pathway
PW:0000558
Pathway Ontology
1908457
PubMed
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