Creatine kinase plays a key role in the energy metabolism of cells with intermittently high and fluctuating energy requirements. Examples of such cells include cardiac or skeletal muscle cells and neural tissues of brain and retina. The enzyme catalyzes the reversible transfer of the phosphoryl group from phosphorylcreatine to ADP, in order to generate ATP.1 The molecular mass of the protein is found to be approximately 80 kDa Da. It is made up of 2 subunits, each having a molecular weight of 40 kDa ± 2000. The lighter subunit is present in larger amounts.
CK; CPK; MM-CK; MB-CK; BB-CK
Molecular Weight: ~81 kDa Creatine Phosphokinase is a dimer composed predominantly of the skeletal muscle derived homodimer (MM). CK also exists as a heterodimer (MB) particularly in the myocardium. CK derived from brain tissue consists mainly of the brain source homodimer (BB). The amino acid sequences of the M chain and B chains are about 80% homologous. From the sequence, the molecular weight of the M chain is 43,112.
Protein determined by biuret.
salt-free, lyophilized powder.
Enzyme Commission Number
> 150 units/mg protein
One unit will transfer 1.0 μmole of phosphate from phosphocreatine to ADP per min at pH 7.4 at 30°C.
pH 8.8-9.0 for the forward reaction and pH 6.0-7.0 for the reverse reaction.
0.25 M glycyl-glycine, pH 7.4: soluble 5.0 mg/mL, clear, colorless to slightly yellow
ADP is a strong inhibitor of the forward reaction competing with ATP. Divalent cations such as Ca2+ (Ki=4.5 mM), Zn2+ and Cu2+ inhibit CK by competing with Mg2+. Other inhibitors include acetate, acetylsalicylic acid, adenosine, p-aminosalicylic acid, AMP, benzoic acid, bicarbonate, bromide, chloride, p-Chloromercuribenzoic acid, ethylene oxide, 2,4-fluorodinitrobenzene, iodide, malonic acid, NAD, nitrate, phosphate, pyrophosphate, salicylic acid, sulfate, sulfite, thyroxine, trichloroacetate, L-triiodothyroxine, L-triiodothyronine, and tripolyphosphate.
EC 184.108.40.206; ATP:creatine phosphotransferase; CK; CPK; MM-CK; MB-CK; BB-CK; creatine phosphokinase; creatine phosphotransferase; phosphocreatine kinase; adenosine triphosphate-creatine transphosphorylase; Mi-CK; CK-BB; CK-MM; CK-MB; CKMiMi; MiMi-CK; 9001-15-4