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-α-D-glucosyl)_n to yield UDP and (1,4-α-D-glucosyl)_n+1.

In other words, this enzyme converts excess glucose residues one by one into a polymeric chain for storage as glycogen. Its presence in the bloodstream is highest in the 30 to 60 minutes following intense exercise. It is a key enzyme in glycogenesis.

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.

References

• Glycogen synthetase. Retrieved on 2007-11-05..