The troponin complex consists of three subunits: Troponin C (TnC), Troponin I (TnI), and Troponin T (TnT). While TnC binds calcium ions and TnT binds to tropomyosin, TnI inhibits the ATPase activity of actomyosin. cTnI is the cardiac-specific isoform of Troponin I, distinguishing it from skeletal muscle isoforms. This specificity makes cTnI a more reliable marker for cardiac muscle injury compared to TnT, which can be found in both cardiac and skeletal muscles.
