phosphorylating

Phosphorylating is the process of introducing a phosphate group, or phosphoryl group, into another molecule. In practice, the term covers both chemical phosphorylation in synthetic chemistry and biological phosphorylation in living systems, where a phosphate moiety is transferred to substrates to form esters, or to regulate activity.

In organic synthesis, phosphorylation typically forms phosphate esters by reacting a hydroxyl-containing substrate with a phosphorylating agent such as phosphoryl chloride (POCl3) or related reagents, followed by hydrolysis. Other approaches use phosphoric acid derivatives, dialkyl phosphorochloridates, or coupling reagents to install the phosphate group. The resulting phosphate esters can be monoesters or, in some routes, more highly substituted phosphates.

In biology, phosphorylation is a reversible post-translational modification in which a phosphate group is transferred to a substrate, typically from ATP, mediated by kinases. Common targets are proteins on serine, threonine, or tyrosine residues; sugar phosphates in metabolism; and phospholipids in membranes. The process often changes the activity, interactions, or localization of the substrate.

Dephosphorylation, carried out by phosphatases, reverses the modification. Phosphorylation cycles regulate signaling pathways, enzyme activity, and metabolism, and are a central feature of cellular regulation. In research, phosphoproteomics and related methods map phosphorylation sites to understand cellular responses and disease processes.