Glycogen synthase

Glycogen synthase (UDP-glucose-glycogen glucosyltransferase') is a glycosyltransferase enzyme (EC number 2.4.1) that catalyses the reaction of UDP-glucose and (1,4- &alpha; -D-glucosyl)n to yield UDP and (1,4- &alpha; -D-glucosyl)n+1.

In other words, this enzyme converts excess glucose residues one by one into a polymeric chain for storage as glycogen.

Regulation
The reaction is highly regulated by allosteric effectors such as glucose-6-phosphate, by phosphorylation reactions, and indirectly triggered by the hormone insulin, which is secreted by the pancreas. Phosphorylation of glycogen synthase decreases its activity.

Pathology
A deficiency is associated with glycogen storage disease type 0.