The overall reaction for the breakdown of glycogen to glucose-1-phosphate is: : 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 α1→4 linkage. Glucose-1-phosphate is converted to glucose-6-phosphate (which often ends up in glycolysis) by the enzyme phosphoglucomutase. Glucose residues are phosphorolysed from branches of glycogen until four residues before a glucose that is branched with a α1→6 linkage. Glycogen debranching enzyme then transfers three of the remaining four glucose units to the end of another glycogen branch. This exposes the α1→6 branching point,α1→6 glucosidase, removing the final glucose residue of the branch as a molecule of glucose and eliminating the branch. This is the only case in which a glycogen metabolite is not glucose-1-phosphate. The glucose is subsequently phosphorylated to glucose-6-phosphate by hexokinase.
Glycogenolysis
Gluconeogenesis
Glyceroneogenesis
Glucose uptake
Proteolysis
Ethanol metabolism
Purine metabolism
Fatty acid metabolism