Glycogen structure: an Evolutionary View

摘要

Muscle glycogen is the fuel for anaerobic glycolysis, a metabolic process to obtain ATP quickly and to support rapid "explosive" movement. The polymer structure of the glycogen molecule is a very efficient way of having a large amount of stored cytoplasmic glucose without a significant increase in osmolarity. Thus, the total amount of fuel stored in liver cells as glycogen (around 10percent by weight) is equivalent to 200-400 mM glucose, whereas the concentration of glycogen is only 3.6-7.2 mu M. In skeletal muscle of a trained runner the concentration of glycogen is about 2 mu M, equivalent to 110 mM glucose (around 1-2percent by weight). The branching structure of glycogen supplies many points for phosphorylase attack, allowing the release of more glucose at the same time.