Why is Troponin C not used for MI diagnosis?
High-Yield Explanation
Ans. (b) troponin C is present in both cardiac and smooth muscleRef: Harrison 19th ed. /265e-7* Troponins of cardiac origin are regulatory proteins that control the calcium mediated interaction of Actin and Myosin.* The troponin complex consists of three subunits: Troponin T, which binds to Tropomyosin and facilitates contractions; Troponin I, which binds to Actin and inhibits Actin/Myosin interaction; and Troponin C, which binds the calcium ions* The amino acid sequence of the skeletal and cardiac isoforms of Troponin T and Troponin I are sufficiently dissimilar and therefore detectable by monoclonal antibody assay.* Troponin C is not used clinically because both cardiac and smooth muscle share Troponin C isoforms