Enzyme Activity Measurement for Creatine Kinase

Creative Enzymes is an industrial biotech company specialized in enzymatic assays. We partner with our diverse and unique customers to support them in new product development and process optimization. The highest quality standard for our services is one of the pillars of our global success and the basis of high-level customer satisfaction. Herein, Creative Enzymes is glad to provide the accurate activity assay for creatine kinase.

Creatine kinase (EC 2.7.3.2; ATP:creatine N-phosphotransferase; CK) is an enzyme that catalyzes the reversible transfer of the N-phosphoryl group from Mg-ATP to creatine (Cr), yielding phosphocreatine (PCr) and Mg-ADP. This enzyme was initially isolated in a crystalline form from skeletal muscles of rabbit. Creatine kinase is a member of the phosphagen (guanidino) kinase family, which is highly conserved and can be found throughout the animal kingdom. Creatine kinase is the only phosphagen kinase found in vertebrates, but it is also found in many invertebrates, such as sponges, polychaetes, and echinoderms. There are four isozymes of creatine kinases, named according to their subcellular localization. For examples, there are two cytosolic forms, the muscle (MM-CK) and brain (BB-CK) forms. There are also two mitochondrial forms of the enzymes, the ubiquitous (uMt-CK) and the sarcomeric (sMt-CK) forms, which have been divided based on their isoelectric point.

Figure 1: The reaction catalyzed by creatine kinase.
Reference: McLeish M J, Kenyon G L. Critical reviews in biochemistry and molecular biology, 2005, 40(1): 1-20.

Creatine kinase is involved in an important system to maintain energy homeostasis of cells with high and fluctuating energy requirement. The high levels of creatine kinase ensured that the levels of ADP and ATP remained almost constant, effectively buffering the cell against rapid depletion of ATP. Additionally, creatine kinase also serves as a clinically important role: the level of creatine kinase can be routinely used as an indicator of myocardial and skeletal muscle disorders, and for the therapy of acute myocardial infarction. Consequently, creatine kinase plays a significant role in energy homeostasis and diagnostics. Thus, measurement of enzyme activity for creatine kinase appears to be necessary for more clinical and pharmaceutical research.

Based on years of experiences on enzyme tests and method optimization, Creative Enzymes is completely qualified for offering the enzymatic assay for creatine kinase precisely. The activity of creatine kinase is determined by continuous spectrophotometric analysis using coupled enzyme systems. Reaction in the forward direction (production of phosphocreatine) may be followed at 340 nm by coupling to pyruvate kinase and lactate dehydrogenase. Conversely, ATP production may also be followed at 340 nm by coupling to hexokinase and glucose-6-phosphate dehydrogenase. The quality of our test results is highly trusted and proven in the global market. Many customers have been loyal to Creative Enzymes for many years. Overall, Creative Enzymes is your best choice for any development involving creatine kinase.

Figure 2: The crystal structure of human brain-type creatine kinase.
PDB: 3DRB