The function of GYG2 (glycogenin 2, Ensembl gene identifier ENSG00000056998) is as follows. Glycogenin participates in the glycogen biosynthetic process along with glycogen synthase and glycogen branching enzyme. It catalyzes the formation of a short alpha (1,4)-glucosyl chain covalently attached via a glucose 1-O-tyrosyl linkage to internal tyrosine residues and these chains act as primers for the elongation reaction catalyzed by glycogen synthase. {ECO:0000269|PubMed:9346895, ECO:0000269|PubMed:9857012}.