Glycogen synthase regulating glycogen/glucose levels and is activated by dephosphorylation. In humans, there are two paralogous isozymes of glycogen synthase: The liver enzyme expression is restricted to the liver, whereas the muscle enzyme is widely expressed. Liver glycogen serves as a storage pool to maintain the blood glucose level during fasting, whereas muscle glycogen synthesis accounts for disposal of up to 90% of ingested glucose. The role of muscle glycogen is as a reserve to provide energy during bursts of activity. Meanwhile, the muscle isozyme plays a major role in the cellular response to long-term adaptation to hypoxia. Notably, hypoxia only induces
(glycogen-synthase-D) phosphatase (glycogen-synthase-D) phosphatase In enzymology, a [glycogen-synthase-D] phosphatase () is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are glycogen-synthase D and HO, whereas its two products are glycogen-synthase I and phosphate. This enzyme belongs to the family of hydrolases, specifically those acting on phosphoric monoester bonds. The systematic name of this enzyme class is [UDP-glucose:glycogen 4-alpha-D-glucosyltransferase-D] phosphohydrolase. Other names in common use include uridine diphosphoglucose-glycogen glucosyltransferase phosphatase, UDP-glycogen glucosyltransferase phosphatase, UDPglucose-glycogen glucosyltransferase phosphatase, glycogen glucosyltransferase phosphatase, glycogen synthetase phosphatase, glycogen synthase phosphatase, glycogen synthase D phosphatase, Mg dependent glycogen synthase phosphatase, and phosphatase type