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. 2018 Sep 21;46(5):1119–1127. doi: 10.1042/BST20170504

Figure 1. Creatine biosynthesis and the myocardial creatine kinase system.

Figure 1.

Creatine is a β-amino acid obtained in the diet from animal products or by de novo synthesis (∼50%). Arginine-glycine amidinotransferase (AGAT, EC 2.1.4.1) located predominantly in the kidney combines glycine and arginine to form the creatine precursor guanidinoacetate (GAA). GAA is carried in the bloodstream to the liver and pancreas, where it is methylated by guanidinoacetate N-methyl transferase (GAMT, EC 2.1.1.2) to form creatine, which is released back into the bloodstream. Uptake into cardiomyocytes is via the specific plasma membrane creatine transporter (SLC6A8), where Mt-CK catalyses the transfer of a phosphoryl group from ATP to form ADP and PCr. PCr accumulates to high levels and is available for the regeneration of ATP at times of high demand catalysed by cytosolic isoforms such as MM-CK. Liberated creatine diffuses back to mitochondria to stimulate further oxidative phosphorylation. Created using Servier Medical Art by Servier which is licensed under a Creative Commons Attribution 3.0 Unported License (http://www.servier.com/slidekit).