Myophosphorylase
Myophosphorylase is an enzyme that plays a crucial role in the glycogenolysis process, specifically in the breakdown of glycogen to glucose-1-phosphate. This enzyme is predominantly found in muscle tissues, hence the name "myo", which is derived from the Greek word for muscle.
Function[edit | edit source]
Myophosphorylase catalyzes the rate-limiting step in glycogenolysis, which is the conversion of glycogen to glucose-1-phosphate. This process is essential for providing energy to the muscles during periods of high-intensity exercise.
Structure[edit | edit source]
The enzyme is a homodimer, meaning it is composed of two identical subunits. Each subunit contains a pyridoxal phosphate (PLP) molecule, which is essential for the enzyme's catalytic activity.
Clinical Significance[edit | edit source]
Deficiency in myophosphorylase leads to a condition known as McArdle's disease, also known as glycogen storage disease type V (GSD V). This is a rare genetic disorder characterized by muscle weakness and fatigue, particularly during strenuous exercise. The condition is caused by mutations in the PYGM gene, which provides instructions for making myophosphorylase.
Treatment[edit | edit source]
There is currently no cure for McArdle's disease. Treatment is focused on managing symptoms and includes a combination of physical therapy, dietary modifications, and in some cases, surgery.
See Also[edit | edit source]
References[edit | edit source]
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Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.Contributors: Prab R. Tumpati, MD