Phosphorylase is an enzyme that breaks down glycogen into glucose-1-phosphate. This process is known as glycogenolysis.

Specifically, phosphorylase acts on the α-1,4 glycosidic bonds within the glycogen molecule, breaking them down to release glucose-1-phosphate.

There are two main types of phosphorylase:

* Glycogen phosphorylase: This is the main form of phosphorylase found in the liver and muscles. It is responsible for breaking down glycogen for energy production.

* Starch phosphorylase: This enzyme is found in plants and breaks down starch into glucose-1-phosphate.

Both types of phosphorylase use inorganic phosphate (Pi) as a cofactor in their enzymatic reactions.