Insulin Insulin Insulin (from Latin "insula", island) is a peptide hormone produced by beta cells of the pancreatic islets; it is considered to be the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of carbohydrates, especially glucose from the blood into liver, fat and skeletal muscle cells. In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats (triglycerides) via lipogenesis, or, in the case of the liver, into both. Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in
Glycogen synthase binding site suggest that the mechanism for synthesis is similar in glycogen synthase and glycogen phosphorylase. Glycogen synthase catalyzes the conversion of the glucosyl (Glc) moiety of uridine diphosphate glucose (UDP-Glc) into glucose to be incorporated into glycogen via an α(1→4) glycosidic bond. However, since glycogen synthase requires an oligosaccharide primer as a glucose acceptor, it relies on glycogenin to initiate "de novo" glycogen synthesis. In a recent study of transgenic mice, an overexpression of glycogen synthase and an overexpression of phosphatase both resulted in excess glycogen storage levels. This suggests that glycogen synthase plays an important biological role in