Creatine kinase M-type (CKM)

Creatine kinase M-type (CKM) is a cytosolic enzyme primarily found in skeletal and cardiac muscle that plays a critical role in cellular energy homeostasis by reversibly transferring phosphate groups between ATP and creatine to generate phosphocreatine and ADP[1][2][3][4][5]. This reaction is central to buffering and rapidly regenerating ATP in tissues with high and fluctuating energy demands. CKM functions as a homodimer (MM-CK) in striated muscle and can act as a heterodimer (MB-CK) in cardiac muscle alongside the brain isoform. Clinically, CKM serves as a general marker of muscle damage and has been used as a serum biomarker for myocardial infarction (though now largely supplanted by more specific markers like troponin), rhabdomyolysis, and other myopathies. CKM is part of the ATP:guanido phosphotransferase family and, while critical to muscle physiology, its diagnostic use is challenged by the lack of tissue specificity and confounding by physiological and iatrogenic factors[1][2][3][4][5].

Other names

Creatine kinase M-typeCKMCKMMCPK-MCreatine kinase M chainCreatine phosphokinase M-typeM-CKMCK

Modulation of high-energy phosphate transfer (e.g., creatine and phosphocreatine supplementation enhances CKM-mediated ATP buffering); Substrate or product for antiviral nucleoside/tide analogs (as with certain antivirals, CKM acts as an enzymatic substrate influencing their metabolism)