an enzyme-catalyzed reaction for the cleavage of chemical bonds in certain biologically important compounds. The reaction involves phosphoric acid, and the phosphoryl group (—H₂PO₃) is incorporated into the reaction products. The enzymes catalyzing the reaction are known as phosphorylases. Phosphorolysis is common in the metabolic processes of animals, plants, and microorganisms.

The bonds that can be broken through phosphorolysis include glycoside (in glycogen), thioether (in the enzyme-substrate complex formed during the oxidation of 3-phosphoglyceraldehyde), carbon-carbon (in xylulose-5-phosphate and pyruvic acid), phosphoester (in nucleic acids), and carbon-nitrogen (in citrulline) bonds. Phosphorolysis is important in the energy balance of organisms because the phosphoryl group introduced into the reaction products is ultimately, under the effect of various enzymes, transferred to adenosine diphosphate to form adenosine triphosphate—the principal energy source of the cell.