Recombinant Human Cardiac Troponin I Protein (T821-GRP)

Troponin is a protein complex located along the thin filaments of myofibrils that regulates the contraction of skeletal and cardiac muscles1, 2, 3. It is composed of three subunits: Troponin T (TnT), Troponin C (TnC), and Troponin I (TnI). TnT attaches to tropomyosin to form a Tn-tropomyosin complex on thin filaments. TnC binds to calcium ions, induces conformational changes in TnI, and acts as an anchoring protein of the Tn complex. TnI inhibits actomyosin ATPase. TnI serves as a biomarker for myocardial infarction (MI)3. During MI, cardiac TnI (cTnI) and TnT (cTnT) are released from injured heart muscles into the bloodstream and their concentrations remain high for several days. The concentration of cTnI rises from ~1-2 ng/mL to ~50 ng/mL within 3–6 hours of MI onset and can reach as high as 500 ng/mL. Since 40% of MI show a normal ECG, and many MI are asymptomatic without apparent chest pain or shortness of breath, precise quantification of cTn levels in a patient’s blood is the “gold standard” for MI diagnosis1, 3. Troponin testing is accomplished by immunoassay, using unique N-terminal peptide sequences that allow for specific detection. A variety of immunoassays utilizing different antibodies and signaling mechanisms have been developed3.