Creatine kinase (CK) is an enzyme expressed by various tissues and cell types. CK catalyses the conversion of creatine and consumes adenosine triphosphate (ATP) to create phosphocreatine and adenosine diphosphate (ADP). This CK enzyme reaction is reversible, such that also ATP can be generated from PCr and ADP. . Description: Human brain. Alternative Names: Creatine Kinase-BB Isoenzyme Protein, CKBB Protein