Description
General description
Research area: Cell Signaling
Creatine phosphokinase (CPK) is an intracellular enzyme found predominantly in skeletal muscle, brain, and myocardium. CPK consists of two polypeptide subunits, namely M (muscle type) and B (brain type). The lighter subunit is present in larger amounts. The genes encoding these subunits are on distinct chromosomes, with B on 14q32 and M on 19q13. These subunits facilitate the development of three tissue-specific isoenzymes: CPK-MB (cardiac muscle), CPK-MM (skeletal muscle), and CPK-BB (brain).
Application
Creatine phosphokinase from bovine heart has been used to investigate whether endothelial cell growth is stimulated by ischemic hearts. Creatine phosphokinase from bovine heart has also been used to evaluate the effect of high but nontoxic dietary intake of copper and selenium on metabolism in calves.
Creatine Phosphokinase from bovine heart has been used:
in the reaction mix for the import of in vitro synthesized wild-type FLAG/MYC-tagged LYR Motif Containing 7 (LYRM7-F/M) or the LFK tripeptide replaced with alanine (LFK-AAA) mutant into isolated mitochondria
in autoubiquitination assay
in the preparation of premix buffer for adenylyl cyclase activity
in the preparation of E-mix for in vitro nuclear assembly and isolation
in in vitro vesicular fusion assay.
in ATP regeneration system, to facilitate the reactivation of nonmotile axonemes.
in subcellular in vitro fusion assay of autophagosome with lysosome.
in in vitro protein translation assay.
for tATPase assay of myofibrillar protein isolated from rabbit. This assay evaluated the kinetic influence of bound creatine kinase (CK) on Ca²⁺-activated myosin ATPase.
for the enzymatic hydrolysis of protein samples during tryptophan estimation by pyrolysis gas chromatography.
Biochem/physiol Actions
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. The molecular mass of the protein is found to be approximately 80,000 Da. It is made up of 2 subunits, each having a molecular weight of 40,000 ± 2000. The lighter subunit is present in larger amounts.CPK is released from the cellular cytosol into the systemic circulation due to disruption of cell membranes caused by hypoxia or other injuries. Furthermore, it serves as a diagnostic indicator for rhabdomyolysis and acute myocardial infarction (AMI), along with other medical disorders such as acute muscle injury, arrhythmias, and congestive cardiac failure.
Analysis Note
Protein determined by biuret.
Other Notes
One unit will transfer 1.0 μmole of phosphate from phosphocreatine to ADP per min at pH 7.4 at 30 °C.
Disclaimer
The use of 0.1% albumin in the reaction buffer is recommended to avoid inactivation due to dilution.
