Glycogen

Branched polysaccharide composed of glucose monomers Glycogen is a white tasteless powder that swells with water to a colloidal solution. The molar mass of glycogen is about 106 to 107 daltons.

Glycogen is present in all animal cells, especially in the liver (liver starch, its mass fraction can be up to 20% in the liver), in muscles (0.5-2.0%) and in blood serum (3.0-70mg/100ml).

Glycogen is used for the short- to medium-term storage and provision of the energy carrier glucose in the human and animal organism. The cells of yeasts and other fungi also use glycogen for energy storage. Plants, on the other hand, use starch as a carbohydrate store.

The process of building up glycogen is called glycogen synthesis, and the breakdown of glycogen is called glycogenolysis (glycolysis). The Embden-Meyerhof-Parnas pathway is the most important anaerobic carbohydrate degradation pathway.

The glycogen stored in the organs is broken down again into glucose as required and made available to the whole organism via the blood.

Structure of glycogen: Glycogen consists of up to 50,000 alpha-1,4-glycosidically linked glucose building blocks. In addition to the alpha-1,4-glycosidic bond, an alpha-1,6-glycosidic bond is formed at certain intervals (every 8-12 molecules). This allows the molecule to branch in a tree-like manner. Amylopectin, a component of plant starch, is structured in the same way as glycogen. Amylopectin has a lower degree of branching (alpha-1,6-glycosidic linkage only with every 25th glucose molecule).