troponin is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that is integral to muscle contraction in skeletal muscle and cardiac muscle, but not smooth muscle.
Troponin C binds to calcium ions to produce a conformational change in TnI
Troponin T binds to tropomyosin, interlocking them to form a troponin-tropomyosin complex
Troponin I binds to actin in thin myofilaments to hold the troponin-tropomyosin complex in place
cardiac I and T subtypes of troponin are sensitive and specific indicators of damage to myocardium and thus are the current main cardiac markers for myocardial injury
troponin elevation following cardiac cell necrosis starts within 2–3 hours, peaks in approx. 24 hours, and persists for 1–2 weeks
aetiology of acutely raised troponin I or T levels