During the early part of the 1900s by using creatine as a supplement allowed for a boost in creatine in animals. Later on, phosphocreatine (creatine phosphate or phosphorylated creatine) was discovered in the year of 1927. Then in 1934, the creatine kinase (the enzyme that “catalyzes” phosphocreatine was found). Finally, in 1968, phosphocreatine was found in the process of recuperating from exercise.
In foods, creatine is found primarily in red meat and fish. Eaten creatine is then eventually sent to the bloodstream. Creatine is also synthesized within the body by the liver, kidney and pancreas, although this primarily takes place in the liver. This is done in two steps: the first step is when an amidine group from arginine goes to glycine to make guanidinoacetic acid. Then in step two, a methyl group goes to a guanidinoacetic acid from S-adenoslymthionine forming creatine. In the synthesis of creatine, there are some controls on it so that when there is less creatine in one’s diet, there will be more synthesis of creatine in the body. In opposition, if there is a lot of creatine present in one’s diet, then there will be less creatine synthesis in the body.
The storage of creatine in the body occurs in two forms; in the form of phosphocreatine or simply creatine. In the average adult male weighing 70kg, there is 120g of creatine of which 95% is found in the skeletal muscle. Some of the creatine goes to other various parts of the body such as the heart and brain. Of all the creatine in the skeletal muscles, 60-70% of that creatine is phosphocreatine. And because it is phosphocreatine, it cannot leave the membranes.