Creatine kinase, mitochondrial 1 (ubiquitous form) (CKMT1A or uMtCK)

Mitochondrial creatine kinase 1 (CKMT1A) is an octameric enzyme located in the mitochondrial intermembrane space that catalyzes the reversible phosphorylation of creatine to phosphocreatine using mitochondrial ATP. The enzyme functions as a critical component of cellular energy metabolism, particularly in tissues with high and fluctuating energy demands such as skeletal muscle, cardiac muscle, and brain. Through the phosphocreatine/creatine shuttle system, mitochondrial creatine kinase 1 enables rapid and efficient energy transfer from mitochondrial ATP production sites to cytosolic sites of ATP consumption, supporting muscle contraction and neural activity. The protein's X-ray crystal structure, solved in 2000 at 2.7 Å resolution, reveals a cuboidal octamer with 422 point group symmetry containing a central channel and membrane-binding motifs essential for its physiological function. While not a traditional pharmaceutical drug target, mitochondrial creatine kinase 1 serves as an important clinical biomarker for detecting tissue damage in conditions including myocardial infarction, rhabdomyolysis, and muscular dystrophy.

Other names

Ubiquitous mitochondrial creatine kinase (uMtCK)Mitochondrial creatine kinase ubiquitous formCKMT1ACKMT1B (alternative isoform)Creatine phosphokinase, mitochondrial

The enzyme catalyzes a reversible phosphoryl transfer reaction: ATP + Creatine ∣ Phosphocreatine + ADP. The ubiquitous mitochondrial form contains structural features including a central channel of approximately 20 Å diameter that extends through the octamer and putative membrane binding motifs.