Glycogen synthesis and Breakdown Pathway Introduction Glycogen is a polysaccharide that consists of glucose molecules linked together by glycosidic linkage. In animals and humans; glucose is stored in the form of glycogen in the liver (~10%) and muscles (~2%). These stored glycogen molecules can readily be degraded into glucose molecules and enter into the glycolytic pathway for energy. Liver glycogen can also contribute to the maintenance of normal blood glucose. The glycogen synthesis and breakdown pathway are highly regulated and, the synthesis and breakdown do not occur at the same time. Glycogenesis F igure 1: Overview of Glycogen synthesis (Glycogenesis) Synthesis of Glycogen The addition of glucose to form glycogen requires a primer molecule where the glucose can be added to the non-reducing ends. During de novo synthesis, glucose molecules are added to tyrosine residues of primer protein glycogen. The enzyme Glycogen synthase ...