Creatine Kinase-MB Assay Kit (CK-MB)
For the in vitro quantitative determination of creatine kinase -MB（CK-MB）in human serum.
CK-MB is present in low concentration in normal human serum but is increased as a result of heart injury, and rarely, skeletal muscle damage. CK-MB is widely used as an indicator of acute myocardial infarction as the detection of elevated activities is considered highly specific for this condition.
Creatine Kinase is a dimer. Its monomeric subunits are designated M and B. The subunits combine to form three isoenzymes namely CKBB, CK-MB and CK-MM. CK-MM and CK-MB are found primarily in skeletal and heart muscle, respectively, while CK-BB is found mainly in the brain and smooth muscle tissue. In serum, the Ck-BB activity can be ignored. M Subunits of CK-MM and CK-MB are inactivated by reaction with anti-M antibody (immunoinhibition). The remaining B-subunit is measured enzymatically.
Creatine kinase
creatine phosphate + ADP → creatine + ATP
Hexokinase
ATP + glucose → ADP + glucose -6-phosphate
G-6-PD
glucose-6-phosphate + NAD → 6-phosphogluconate + NADH
Through a series of coupled enzymatic reactions, NADH is produced at a rate directly proportional to the CK B subunit activity. Multiply the activity by 2, and this result is just the activity of CK-MB.
- Tietz, N. W, Textbook of Clinical Chemistry, W.B. Saunders Co,Philadelphia, 1986, p. 678-6863.
- Szasz, G., et al. Clin. Chem 1976; 22: 650.
- Recommendations of the German Society for Clinical Chemistry.Standardization of methods for the estimation of enzyme activities in biological fluids:Standard method for the determination of creatine kinase activity. J Clin Chem Clin Biochem 1977; 15:255-60.