KreatinKinase

Kreatinkinase, often abbreviated as CK or CPK, is an enzyme found predominantly in muscle tissue, as well as in the brain and heart. Its primary function is to catalyze the reversible transfer of a phosphate group from creatine to adenosine diphosphate (ADP), forming adenosine triphosphate (ATP), the main energy currency of the cell. This reaction is crucial for providing rapid energy during periods of high cellular demand, such as muscle contraction.

Measuring kreatinkinase levels in the blood is a common diagnostic tool in medicine. Elevated levels can indicate damage to muscle tissue. The enzyme is released into the bloodstream when muscle cells are injured or undergo necrosis. Therefore, elevated CK levels can be associated with a variety of conditions, including muscle diseases like muscular dystrophy and rhabdomyolysis, as well as heart attacks, where damage to cardiac muscle occurs.

There are different isoenzymes of kreatinkinase, each predominantly found in specific tissues. Creatine kinase-muscle (CK-MM) is the most common form and is found in skeletal muscle. Creatine kinase-heart (CK-MB) is found in cardiac muscle, and its elevation is a specific indicator of myocardial infarction. Creatine kinase-brain (CK-BB) is primarily found in the brain and smooth muscle. The relative proportions of these isoenzymes can help pinpoint the source of muscle damage. Other factors, such as strenuous exercise, certain medications, and intramuscular injections, can also temporarily increase CK levels.