Creatine kinase (CK) (CK)

Creatine kinase (CK) is a vital enzyme that maintains cellular energy homeostasis by catalyzing the reversible transfer of a high-energy phosphate group between adenosine triphosphate (ATP) and creatine to form phosphocreatine (PCr) and adenosine diphosphate (ADP) [7, 21]. This enzymatic activity powers the phosphocreatine-ATP shuttle, a metabolic circuit that facilitates the rapid transport of high-energy phosphates from sites of production in the mitochondria to sites of utilization at various cellular ATPases [6, 9]. CK exists in several tissue-specific isoforms, including CK-MM in skeletal muscle, CK-MB in cardiac muscle, and CK-BB in the brain, as well as mitochondrial forms (Mt-CK) that are functionally coupled to oxidative phosphorylation [1, 13]. Clinically, CK is a cornerstone biomarker for detecting tissue damage, particularly in the diagnosis of myocardial infarction and rhabdomyolysis [10, 18]. From a therapeutic perspective, the CK system is a target for metabolic modulation; creatine supplementation is used to enhance energy resilience in neurodegenerative and cardiovascular diseases, while CK inhibitors are being investigated for their potential to disrupt the hypermetabolic state of certain cancers [3, 14]. The system's role as a temporal and spatial energy buffer is especially critical in tissues with high and fluctuating energy demands, such as the heart and brain [12, 13]. Therapeutic challenges include the need for tissue-specific modulation to avoid off-target effects in other CK-rich organs [14, 15].

Other names

Creatine phosphokinaseCPKPhosphocreatine kinaseCK/PCr shuttleCreatine kinase system

ATP regeneration, phosphocreatine synthesis, energy buffering, and substrate channeling.