Glycogenin-1 is an enzyme that is involved in the biosynthesis of glycogen. It is capable of self-glucosylation, forming an oligosaccharide primer that serves as a substrate for glycogen synthase. This is done through an inter-subunit mechanism. It also plays a role in glycogen metabolism regulation. Recombinant human glycogenin-1 was expressed in E. coli and purified using conventional chromatography techniques.