Phosphocreatine

Adenosine triphosphate (ATP) is the primary source of chemical energy that body muscles use to perform contractions. During such contraction processes, ATP molecules are depleted as they undergo hydrolysis reactions and become adenosine diphosphate (ADP). To maintain homeostasis in muscle activity, the ATP supply of muscles must be regenerated regularly.

Phosphocreatine occurs naturally within the body and is capable of regenerating ATP by transferring a high-energy phosphate from itself to ADP, resulting in the formation of ATP and creatine. This kind of regeneration of ATP with phosphocreatine typically occurs within seconds of intense muscular or neuronal effort, acting as a quickly accessible reserve of high-energy phosphates for the recycling of ATP in body muscle tissues. ATP recycling from phosphocreatine is in fact known as the quickest form of ATP regeneration.