Description
Creatine kinase (CK) s an enzyme that consists of two subunits, which can be either B (brain type) or M (muscle type). Three different isoenzymes exist: CKBB, CKMM, and CKMB. This enzyme expressed by various tissues and cell types. Heart muscle expresses CKMM at 70%, CKMB at 25-30%. CK catalyses the conversion of creatine and consumes adenosine triphosphate (ATP) to create phosphocreatine (PCr) and adenosine diphosphate (ADP). This CK enzyme reaction is reversible, so that also ATP can be generated from PCr and ADP. Creatine kinase's clinical significance: detection of heart disease, liver disease, diseases of the central nervous system and thyroid disease