Phosphorolysis


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phosphorolysis

[‚fäs·fə′räl·ə·səs]
(biochemistry)
A reaction by which elements of phosphoric acid are incorporated into the molecule of a compound.

Phosphorolysis

 

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.

A. D. VINOGRADOV

References in periodicals archive ?
It catalyzes the first step of glycogenolysis, in which glycogen is converted to glucose 1-phosphate by phosphorolysis in the presence of inorganic phosphate, and through mobilization of glycogen, it is primarily associated with provision of an emergency glucose supply during periods of hypoxia and hypoglycemia.
GP is an allosteric enzyme that catalyzes the degradative phosphorolysis of glycogen to glucose 1-phosphate.
GPb activity in the direction of phosphorolysis of glycogen was measured using the auxiliary assay system as described by Helmreich and Cori (24) with some modifications.