Phosphorylated form of creatine, q.v. Occurs primarily in skeletal muscle; also found in heart and brain. Involved in the transfer of high energy phosphate to ADP. Isoln from frog muscle: Eggleton, Biochem. J. 21, 190 (1927); from cat muscle: Fiske, Subbarow, J. Biol. Chem. 81, 629 (1929). Synthesis by phosphorylation of creatine: Zeile, Fawaz, Z. Physiol. Chem. 256, 193 (1938); Ennor, Stocken, Biochem. J. 43, 190 (1948). Enzymic determn in skeletal muscle: K. Yoshikawa et al., Anal. Biochem. 159, 303 (1986). HPLC determn in cardiac muscle: T. Teerlink et al., Anal. Biochem. 214, 278 (1993). Clinical trial as cardioprotective: M. L. Semenovsky et al., J. Thorac. Cardiovasc. Surg. 94, 762 (1987); as antiarrhythmic: M. Y. Ruda et al., Am. Heart J. 116, 393 (1988). Review of role in energy metabolism: S. P. Bessman, C. L. Carpenter, Annu. Rev. Biochem. 54, 831-862 (1985).
Cardioprotective.