Degradation of stored glycogen, termed glycogenolysis , occurs through one of two pathways, cytosolic and lysosomal. The cytosolic pathway involves the actions of glycogen phosphorylase (GP; often referred to simply as phosphorylase) and the glycogen debranching enzyme (GDE). Glycogenolysis is the breakdown of glycogen to glucose-1-phosphate and glycogen in muscle and liver cells. Learn about the mechanism, function, regulation and clinical significance of this process, as well as the enzymes and pathways involved. In the previous section, you learned that glucagon signaling down-regulates glycogen synthesis. Now, let's look at glycogen breakdown, called glycogenolysis , and its control by two hormones, glucagon and epinephrine. Only two enzymes are required for the breakdown of glycogen: the glycogen phosphorylase enzyme and the glycogen debranching enzyme. Glycogenolysis Glycogenolysis is the process of breaking down glycogen into glucose. It occurs when blood glucose levels fall, ensuring that normal blood sugar levels are maintained. 1.0 Introduction and Structure of Glycogen
