Glycogen storage disease type 0 Glycogen storage disease type 0 Glycogen storage disease type 0 is a disease characterized by a deficiency in the glycogen synthase enzyme (GSY). Although glycogen synthase deficiency does not result in storage of extra glycogen in the liver, it is often classified as a glycogen storage disease because it is another defect of glycogen storage and can cause similar problems. There are two isoforms (types) of glycogen synthase enzyme; GSY1 in muscle and GSY2 in liver, each with a corresponding form of the disease. Mutations in the liver isoform (GSY2), causes fasting hypoglycemia, high blood ketones, increased free fatty acids
Glycogen synthase Glycogen synthase Glycogen synthase (UDP-glucose-glycogen glucosyltransferase) is a key enzyme in glycogenesis, the conversion of glucose into glycogen. It is a glycosyltransferase () that catalyses the reaction of UDP-glucose and (1,4-α-D-glucosyl) to yield UDP and (1,4-α-D-glucosyl). Much research has been done on glycogen degradation through studying the structure and function of glycogen phosphorylase, the key regulatory enzyme of glycogen degradation. On the other hand, much less is known about the structure of glycogen synthase, the key regulatory enzyme of glycogen synthesis. The crystal structure of glycogen synthase from "Agrobacterium tumefaciens", however, has been determined at 2.3 A resolution. In its