Creatine

A compound the body synthesizes (makes) and then utilizes to store energy. The storage of energy occurs when phosphate molecules are attached to creatine to create creatine phosphate. Creatine phosphate is capable of donating phosphate to ADP in order to make ATP. ATP can then be converted into ADP with release of energy. Creatine is sold as a dietary supplement and is used by athletes as a "legal steroid" to increase muscle bulk. There has been some concern about the long-term safety of creatine, particularly as to whether it may cause digestive, muscular and cardiovascular problems and possibly raise the risk of cancer.

* * *

N-(Aminoiminomethyl)-N-methylglycine; occurs in urine, sometimes as such, but generally as creatinine, and in muscle, generally as phosphocreatine. Elevated in urine in individuals with muscular dystrophy.

- c. kinase (CK) an enzyme catalyzing the reversible transfer of phosphate from phosphocreatine to ADP, forming c. and ATP; of importance in muscle contraction. Certain isozymes are elevated in plasma following myocardial infarctions. SYN: c. phosphokinase.

- c. phosphate SYN: phosphocreatine.

- c. phosphokinase (CPK) SYN: c. kinase.

* * *

cre·atine 'krē-ə-.tēn, -ət-ən n a white crystalline nitrogenous substance C₄H₉N₃O₂ found esp. in vertebrate muscle either free or as phosphocreatine

* * *

n.

a product of protein metabolism found in muscle. Its phosphate, creatine phosphate (phosphocreatine, phosphagen), acts as a store of high-energy phosphate in muscle and serves to maintain adequate amounts of ATP (the source of energy for muscular contraction).

* * *

cre·a·tine (kreґə-tin) [Gr. kreas flesh] an amino acid formed by methylation of guanidinoacetic acid, found in vertebrate tissues, particularly in muscle. Phosphorylated creatine (see phosphocreatine) is an important storage form of high energy phosphate, the energy source for muscle contraction.