The glycogen is the main reserve polysaccharide in animals, as well as the starch is the plant. It is a polymer formed by glucose residues joined by glycosidic bonds. It is estimated that a glycogen molecule contains about 60,000 glucose residues.
→ Where is glycogen found?
Glycogen is present in all cells of an animal, being more abundant in liver cells and skeletal striated muscles. In the liver, the amount of glycogen after a carbohydrate-rich meal amounts to 6% of the organ’s weight. In the muscles, this reserve can present 0.7% of the tissue weight.
→ What are the functions of glycogen?
Glycogen acts as a form of sugar storage. In the liver, the production and degradation of glycogen are essential to supply the body’s needs, ensuring the maintenance of blood glucose between meals. The glycogen in the liver acts as a glucose reserve, which, when necessary, is used and also taken to other organs.
In muscle, the processes of synthesis and degradation are performed only to supply the needs of this tissue. The muscle uses this reserve when it is used a lot, such as during a run.
→ Glycogen synthesis and degradation
The gluconeogenesis is the process name in which it forms a glycogen molecule from simpler molecules. It occurs when energy levels and glucose supplies are high.
In glycogenesis, the transfer of glucose residues occurs, which bind to free hydroxyl groups present in the glucose residues that are found in the most peripheral portions. The regulation of glycogenesis occurs essentially by glycogen synthase.
The glycogenolysis is the process in which degradation of glycogen and happens when the energy levels and glucose supplies are low. The process consists of removing terminal glucose residues. The regulation of glycogenolysis occurs essentially by glycogen phosphorylase.