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Metabolic
Animals, fungi
Glycogen Metabolism
Synthesis and degradation of glycogen for glucose storage and release.
Overview
Glycogen metabolism involves two opposing processes: glycogenesis (synthesis) and glycogenolysis (breakdown). Glycogen synthase catalyzes the addition of glucose units to glycogen chains, while glycogen phosphorylase cleaves glucose-1-phosphate from glycogen. These processes are reciprocally regulated by hormones (insulin, glucagon, epinephrine) through covalent modification and allosteric control.
Cellular Location
Cytoplasm (liver, skeletal muscle)
Clinical Significance
Primary short-term glucose storage; glycogen storage diseases (McArdle, Von Gierke) result from enzyme deficiencies; key to exercise physiology.