Glycogen synthase expression of the muscle isozyme and not the liver isozyme. However, muscle-specific glycogen synthase activation may lead to excessive accumulation of glycogen, leading to damage in the heart and central nervous system following ischemic insults. The reaction is highly regulated by allosteric effectors such as glucose-6-phosphate (activator) and by phosphorylation reactions (deactivating). Glucose-6-phosphate allosteric activating action allows glycogen synthase to operate as a glucose-6-phosphate sensor. The inactivating phosphorylation is triggered by the hormone glucagon, which is secreted by the pancreas in response to decreased blood glucose levels. The enzyme also cleaves the ester bond between the C1 position of glucose
(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