Creatine(redirected from creatine kinase (CK))
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N-methylguanidoacetic acid. Molecular weight, 131.14; melting point, 315°C (with dissociation):
Creatine is soluble in hot water, slightly soluble in alcohol, and insoluble in ether. The interaction of mineral acids and creatine produces the lactam creatinine. This reaction is the basis of one of the methods used to determine creatine content. Creatine dissociates into urea and methylglycine in an alkaline medium.
Creatine was discovered in 1835 by the French scientist M. Chevreul in extracts from skeletal muscles. It is found in the muscle tissue of all vertebrates (approximately 0.5 percent of the muscle weight) in the form of the unstable creatinephosphoric acid, which takes part in supplying the energy required for muscle contraction. Smaller quantities are present in nerve tissue, blood, liver, and kidneys. Creatine biosynthesis in an organism is achieved in the kidneys from the amino acids glycine and arginine, forming glycocyamine. The glycocyamine undergoes subsequent methylation in the liver in the presence of the amino acid methionine to yield creatine.
N. P. MESHKOVA