CKMBITI Human

Creatine kinase (CK) is an enzyme that plays a crucial role in cellular energy homeostasis. It catalyzes the reversible transfer of a phosphate group from adenosine triphosphate (ATP) to creatine, forming phosphocreatine and adenosine diphosphate (ADP). This reaction is vital for the rapid regeneration of ATP, especially in tissues with high and fluctuating energy demands such as skeletal muscle, cardiac muscle, and the brain.

Creatine kinase exists in three isoenzymatic forms:

1. CK-MM: Predominantly found in skeletal muscle.
2. CK-BB: Mainly present in the brain.
3. CK-MB: Primarily located in cardiac muscle but also found in smaller amounts in skeletal muscle.

The CK-MB isoenzyme is of particular clinical interest because it serves as a biomarker for myocardial injury, such as that occurring during a heart attack.

Recombinant human creatine kinase MB isoenzyme (r-hCK-MB) is produced using recombinant DNA technology. This involves the insertion of cDNAs encoding the CK-M and CK-B subunits into a plasmid vector, which is then transformed into a host organism, typically Escherichia coli. The host organism expresses the CK-MB isoenzyme, which can then be purified for various applications.

The production of r-hCK-MB involves several steps:

1. Cloning: cDNAs encoding the CK-M and CK-B subunits are amplified using polymerase chain reaction (PCR) and inserted into a plasmid vector.
2. Transformation: The plasmid vector is introduced into Escherichia coli cells, which then express the CK-MB isoenzyme.
3. Purification: The expressed CK-MB isoenzyme is purified using conventional chromatography techniques. The purified enzyme retains the key properties of the native cardiac isoenzyme, including its isoelectric point and molecular size .

Recombinant human CK-MB isoenzyme has several important applications:

1. Clinical Diagnostics: It is used as a control and calibrator in assays for measuring CK-MB levels in serum, which is crucial for diagnosing myocardial infarction.
2. Research: It serves as a valuable tool in research related to muscle physiology, energy metabolism, and neuromuscular diseases .

The recombinant CK-MB isoenzyme exhibits high stability, retaining over 90% of its activity for at least four months when stored at 11°C in a delipidated serum matrix. This stability makes it a reliable standard for clinical and research applications .