Phosphorolyze

Phosphorolyze is the act of cleaving a chemical bond by the addition of a phosphate group. In biochemistry, the term is most often used in reference to phosphorolysis, the enzymatic cleavage of glycosidic bonds by inorganic phosphate to produce a sugar phosphate and a shortened sugar. The concept can also apply to other bond types, including the cleavage of nucleosides by phosphate to give a base and a sugar phosphate.

Most phosphorolysis reactions are catalyzed by phosphorylases. The mechanism involves nucleophilic attack by phosphate on the target bond, displacing the remaining fragment as a free molecule, typically yielding a sugar phosphate such as glucose-1-phosphate. Many phosphorolysis reactions are reversible; the forward direction depends on concentrations of phosphate and product sugar phosphate.

Example enzymes and pathways include glycogen phosphorylase, which cleaves α-1,4-glycosidic bonds in glycogen to form glucose-1-phosphate, and starch phosphorylase in plants, which degrades starch to glucose-1-phosphate. In nucleotide metabolism, nucleoside phosphorylases catalyze phosphorolysis of nucleosides to give a base and ribose-1-phosphate or deoxyribose-1-phosphate. These reactions integrate with central metabolism by providing sugar phosphates for glycolysis and related pathways.

Phosphorolysis differs from hydrolysis in that water is not required for bond cleavage; instead, inorganic phosphate serves as the nucleophile. This pathway enables direct production of metabolic intermediates and has applications in biotechnology for producing sugar phosphates and in metabolic studies.