Glycogenolysis is the breakdown of glycogen (n) to and glycogen (n-1). Glycogen branches are catabolized by the sequential removal of glucose monomers via phosphorolysis, by the enzyme glycogen phosphorylase.

glycogen(n residues) + Pi ⇌ glycogen(n-1 residues) + glucose-1-phosphate

Here, glycogen phosphorylase cleaves the bond linking a terminal glucose residue to a glycogen branch by substitution of a phosphoryl group for the α[1→4] linkage. Glucose-1-phosphate is converted to (which often ends up in glycolysis) by the enzyme phosphoglucomutase.

Yeast glycogen phosphorylase dimer with pyridoxal-5-phosphate and phosphate (PDB entry 1ygp)

Drag the structure with the mouse to rotate

ReferencesReferences

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

Alexander Berchansky