University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

52

Pages:

6
Author:

Sheha A.

Glycogenesis Glycogen is an animal storage polysaccharide. It is synthesized during fed condition (excess sugar) and broken down during fasting condition. Definition: Formation of glycogen from glucose is called glycogenesis. Site: Liver and muscles Subcellular Site: Cytosol Building Compound: Glucose Glycogen Synthesis 1) Activation of Glucose: UDP-glucose is the activated form of glucose in glycogen synthesis. Glucose + ATP → Glucose-1-phosphate → UDP-glucose UDP-glucose is the carrier of glucose in glycogen synthesis. 2) Lengthening of Chain & Formation of Glycogen: Glycogen Synthase: The enzyme that catalyzes the addition of glucose units to the growing glycogen chain. Glycogen Primer: A pre-existing short chain of glycogen that acts as a starting point for the addition of glucose units. Branching Enzyme: An enzyme that introduces branches into the glycogen molecule, increasing its solubility and storage capacity. Glycogen Synthesis 3) Change the chain of 11 glucose length: To a minimum of 11 glucose length, a second enzyme, a branching enzyme, adds a new α (1→6) linkage point. 4) Branching: This a branching enzyme adds (1→6) linked glucosyl residues to the non-reducing ends of the growing chain. Significance: Glycogen is an animal storage polysaccharide. It is stored in the liver and muscles. Muscles When the blood glucose increases, glucose is converted into glycogen Regulation of Glycogen Synthesis Glycogen synthase is the regulated enzyme of glycogenesis. The phosphorylated form of glycogen synthase is inactive, whereas the dephosphorylated form of glycogen synthase is active. Glycogen synthase activity is decreased by adrenaline and enhanced by insulin.