ATP hydrolysis

Catabolic reactions synthesize ATP and anabolic reactions utilize it. For example, in the mechanical work of muscle contraction, ATP supplies the energy to move the contractile muscle proteins.

When used, ATP is hydrolysed to produce ADP, an inorganic phosphate ion (P_i), and the release of free energy. The process of hydrolysis breaks complex macromolecules apart using water molecules. In the process, a water molecule is split into a hydrogen atom (H+) and a hydroxyl group (OH-), which are added to the larger molecule.

ATP + H₂O → ADP + energy + P_i + OH^- + H⁺

To carry out life processes, ATP is continuously broken down into ADP, and like a rechargeable battery, ADP is continuously regenerated into ATP by the reattachment of a third phosphate group.

It is estimated that we consume more than 50 kg of ATP per day.