gammafosfato

Gamma phosphate refers to the terminal phosphate group of ATP, the third phosphate in the triphosphate chain. In ATP, the three phosphates are named alpha, beta, and gamma, with gamma being the outermost group attached to the beta phosphate. The phosphates are linked by high-energy phosphoanhydride bonds, and the gamma phosphate is the one most commonly involved in energy release and transfer.

In cellular metabolism, hydrolysis of ATP often occurs at the gamma phosphate. ATPases catalyze the reaction ATP + H2O → ADP + inorganic phosphate (Pi), releasing energy that powers many biological processes such as muscle contraction, transport across membranes, and synthesis of macromolecules. The energy yield is influenced by factors including magnesium ions and cellular conditions.

Gamma phosphate also participates in phosphorylation reactions. Kinases transfer the gamma phosphate from ATP to specific substrates, such as proteins, lipids, or sugars, altering their activity, localization, or interactions. This gamma phosphate transfer is a central mechanism in signal transduction and metabolic regulation.

In laboratory settings, gamma-32P-labeled ATP is used to study phosphorylation events, enabling detection and quantification of phosphate transfer during enzymatic reactions.

The gamma phosphate's role as the primary energy- and phosphate-donor in many biological processes makes it a key element in bioenergetics and cellular signaling.