Glycogen-branching enzyme participates in the glycogen biosynthetic process along with glycogenin and glycogen synthase. Generates alpha-1,6-glucosidic branches from alpha-1,4-linked glucose chains, to increase solubility of the glycogen polymer (PubMed:26199317, PubMed:8463281, PubMed:8613547). {ECO:0000269|PubMed:26199317, ECO:0000269|PubMed:8463281, ECO:0000269|PubMed:8613547}. This is the function of Ensembl gene identifier ENSG00000114480 (GBE1, 1,4-alpha-glucan branching enzyme 1).