CTn
Cardiac troponin, or cTn, is a protein complex that regulates contraction in heart muscle. It consists of three subunits: troponin C (cTnC), troponin I (cTnI) and troponin T (cTnT). In humans, the cardiac-specific isoforms are cTnI and cTnT, encoded by TNNI3 and TNNT2, while cTnC has both cardiac and skeletal forms. Clinically, measurement of cTnI or cTnT in blood is a sensitive marker of cardiomyocyte injury.
Functionally, the troponin complex sits on the thin filament of the sarcomere. When calcium binds to cTnC,
In medicine, cardiac troponins I and T are used primarily as biomarkers for myocardial injury. High-sensitivity
Timing is important: troponins typically rise within a few hours of injury, peak within about a day,