8 UDP-glucose + glycogenin dimer => 8 UDP + {(1,4)-alpha-D-glucosyl}4 glycogenin dimer EC Number: 2.4.1.186 Glycogenin catalyzes its own reaction with UDP-glucose to synthesize an oligo (1,4)-alpha-D-glucosyl chain attached to itself (Mu et al. 1997; Mu and Roach 1998). The oligosaccharide is annotated here as containing four glucose residues. Glycogenin occurs as a homodimer associated with glycogen granules in the cytosol (Wilson et al. 2007).<p>Glycogenin proteins are encoded by two human genes, GYG1 and GYG2. Multiple isoforms of each protein due to alternative splicing have been described, but none of these isoforms has yet been associated with a distinctive function. GYG1 protein is abundant in skeletal muscle while GYG2 is abundant in liver. Human GYG2 has been characterized biochemically (Mu et al. 1997; Mu and Roach 1998) but while the role of human GYG1 in muscle glycogen metabolism during exercise has been studied (Wilson et al. 2007), details of its structure and catalytic activities are inferred from those of its rabbit homologue (e.g., Gibbons et al. 2002). Pubmed12051921 Pubmed17311895 Pubmed9346895 Pubmed9857012 Reactome Database ID Release 4370290 Reactome, http://www.reactome.org ReactomeREACT_1902 has a Stoichiometric coefficient of 8 oligo((1,4)-alpha-glucosyl) glycogenin dimer GYG1, GYG2