What does phosphorylase mean?
Phosphorylase is a biochemical enzyme that breaks a chemical bond by a process called phosphorolysis. Rather than using water, as many bond-breaking enzymes do, it uses inorganic phosphate to split the substrate. Its best-known form is glycogen phosphorylase, which acts on stored glycogen and releases glucose-1-phosphate. This reaction is important in muscle and liver metabolism, helping make stored carbohydrate available for energy. Phosphorylase activity is tightly regulated, particularly through phosphorylation and through the enzyme phosphorylase kinase. The term is primarily used in biochemistry, physiology, and medical research. Although “phosphorylase” can refer to the broad class of phosphate-dependent cleaving enzymes, it most often denotes glycogen phosphorylase when no substrate is specified. It should not be confused with phosphatase, which acts on phosphate groups and hydrolyzes phosphate-containing compounds using water.
nounAn enzyme that catalyzes phosphorolysis, a reaction in which phosphate is used to cleave a chemical bond. The best-known example is glycogen phosphorylase, which releases glucose-1-phosphate from glycogen.
- Any enzyme that catalyzes phosphorolysis, a cleavage reaction involving inorganic phosphate.
"Glycogen phosphorylase was activated as the muscles began to consume stored glycogen during exercise."
"The liver increased phosphorylase activity in response to glucagon."
"Mutations affecting the enzyme's regulation can impair the breakdown of glycogen in muscle."
Used when referring to more than one enzyme in the phosphorylase class or to different forms of the enzyme.
"Several phosphorylases have been identified in plant tissues."
Phosphorylase does not merely add phosphate to a molecule: it uses phosphate as a tool to cut one apart.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of phosphorylase
The word is formed from “phosphoryl” and the enzyme suffix “-ase.” Both elements ultimately connect with Greek phōs, meaning “light,” and phoros, meaning “bearing,” through the element phosphorus. The suffix “-ase” was adopted in the nineteenth century to denote enzymes, following conventions established for digestive enzymes such as pepsin and trypsin.
How phosphorylase is actually used
This is a specialist biochemical term used chiefly in scientific and medical contexts. In the best-known sense, it refers to enzymes involved in carbohydrate metabolism, especially glycogen phosphorylase.
Easily confused with phosphorylase
A phosphorylase uses inorganic phosphate to break a chemical bond, whereas a phosphatase hydrolyzes a phosphate-containing compound by using water.