label: glycogenin glucosyltransferase activity
label_lc: glycogenin glucosyltransferase activity
description: "Catalysis of the reaction: UDP-glucose + glycogenin = UDP + glucosylglycogenin. This first reaction is a self glucosylation. Further UDP-glucose goups are added to the [1,4-alpha-D-glucosyl](n) group of glycogenin until a length of about 5-13 residues."