Biochemistry in Tables, Schemes, and Graphs - S.D. Zhamsaranova 2009

Metabolism and Functions of Carbohydrates
Glycogen Breakdown – Glycogenolysis

Glycogen breakdown—Glycogenolysis—occurs during the fasting state between meals.

The release of glucose as glucose-1-phosphate results from phosphorolysis catalyzed by phosphorylase. The enzyme removes terminal residues one by one, thereby shortening the glycogen chains. However, this enzyme only cleaves a-1,4-glycosidic bonds. The bonds at the branch points are hydrolyzed by the enzyme amylo-a-1,6-glucosidase, which releases a free glucose monomer.

Class="center">

FEATURES OF GLYCOGEN MOBILIZATION IN The Liver and Muscles

The physiological significance of glycogenolysis differs between the liver and skeletal muscles. Muscle glycogen serves as a local energy source for the muscle Cell itself, whereas liver glycogen is primarily utilized to maintain physiological Blood glucose levels. These differences stem from the fact that hepatocytes contain the enzyme glucose-6-phosphatase, which catalyzes the removal of the phosphate group to yield free glucose, which then enters the bloodstream. Muscle Cells lack this enzyme; consequently, glycogen breakdown proceeds only as far as glucose-6-phosphate, which is subsequently metabolized within The Cell.

SELECTED FORMS OF Glycogen Storage Diseases

Type of glycogen storage disease

Deficient enzyme

Localization of the deficient enzyme

Von Gierke disease

Glucose-6-phosphatase

Liver, Kidneys

Pompe disease

a-1,4-glucosidase (lysosomal)

All Organs

Cori disease

amylo-a-1,6-glucosidase

Liver, cardiac and skeletal muscles, leukocytes

Andersen disease

Branching enzyme

Liver, muscles, kidneys

Hers disease

Phosphorylase (hepatic)

Liver


Last update: 06/08/2026

Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.

What was processed:

  • elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
  • editorial organization of content;
  • standardization of terminology in accordance with academic sources;
  • verification of factual statements against the original source text.

All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.