ATP- 18 O 4 (disodium salt) is the 18 O labeled ATP disodium salt. ATP disodium salt (Adenosine 5'-triphosphate disodium salt) is a central component of energy storage and metabolism in vivo, provides the metabolic energy to drive metabolic pumps and serves as a coenzyme in cells. ATP disodium salt is an important endogenous signaling molecule in immunity and inflammation.