The breakdown of glycogen, known as glycogenolysis, involves the enzyme glycogen phosphorylase, which cleaves glucose units from the glycogen molecule as glucose-1-phosphate. This is subsequently converted to glucose-6-phosphate. In the liver, glucose-6-phosphate can be dephosphorylated to free glucose and released into the bloodstream, whereas in muscle, it enters the glycolytic pathway to provide energy for muscle contractions.
