Introduction to phosphocreatine

A high-energy phosphate compound in muscles or other excitatory tissues, such as the brain and nerves, that is a temporary storage form of high-energy phosphate groups. When phosphocreatine is hydrolyzed, 10.3 kcal of free energy is released per mole of compounds, which is more than the energy released by ATP (7.3 kcal per mole). Phosphocreatine can transfer its phosphate group to the ADP molecule catalyzed by creatine kinase. ADP is produced when some ATP is used for muscle contraction. At this point, phosphocreatine rapidly provides a phosphate group to ADP through the action of creatine kinase, thereby restoring normal high levels of ATP. Since the content of phosphocreatine in muscle cells is 3~4 times that of ATP, the former can store enough phosphate groups for short-term activities. During the recovery period after activity, the accumulated creatine can be phosphorylated again by ATP to regenerate phosphocreatine, which is an opposite reaction catalyzed by the same enzyme. Since there are no other metabolic pathways within the cell to synthesize and break down phosphocreatine, this compound is well suited to perform this temporary storage function. In many invertebrates, phosphoarginine replaces phosphocreatine as a form of energy storage. The role of phosphocreatine can be illustrated by using human sprints as an example. The amount of phosphocreatine in the muscles is 17 micromol/g. A full-throttle sprint can burn 13 micromoles/g of phosphocreatine, so it can only be used as an energy source for the first 4 seconds, but it can provide time to regulate the activity of glycolytic enzymes and allow muscles to get energy through fermentation.

In vertebrates, creatine reversibly produces phosphocreatine by reacting with ATP, which is catalyzed by creatine kinase.

Phosphocreatine

Medical use: Heart problems.

Athletic uses: Creatine is an amino acid that can improve muscle strength. It can be used in combination with protein synthesis hormones for best results.