Phosphocreatine

Phosphocreatine, also known as creatine phosphate or Pcr, is a phosphorylated creatine molecule that is an important energy store in skeletal muscle. It is used to anaerobically generate ATP from ADP, forming creatine for the 2 to 7 seconds following an intense effort. It does that by donating a phosphate group and this reaction is catalyzed by creatine kinase (presence of creatine kinase in plasma is indicative of tissue damage and is used in the diagnosis of myocardial infarction). This reaction is reversible and it therefore acts as a spatial and temporal buffer of ATP concentration. In other words, Phosphocreatine is part of a coupled reaction; the energy given off from one reaction is used to regenerate the other compound - be it ATP or PC. Phosphocreatine plays a particularly important role in tissues that have high, fluctuating energy demands such as muscle and brain.

Creatine phosphate is synthesized in the liver, and transported to the muscle cells, via the bloodstream, for storage.

History
Phosphocreatine was discovered by David Nachmansohn.