Cardiac troponin I (cTnI)

Cardiac troponin I, often denoted as cTnI, is presented in cardiac muscle tissue by a single isoform with a molecular weight of 23.9 kDa. It consists of 209 amino acid residues. The theoretical pI of cTnI is 9.05. Phosphorylation of cTnI changes the conformation of the protein and modifies its interaction with other troponins and the interaction with anti-TnI antibodies. These changes alter the myofilament response to calcium and are of interest in targeting heart failure. Multiple reaction monitoring of human cTnI has revealed 14 phosphorylation sites, and the pattern of phosphorylation observed in these sites is changed in response to disease. Ctni antibody is considered more sensitive and significantly more specific in the diagnosis of myocardial infarction than the "golden marker" of last decades – ckmb protein, as well as total creatine kinase, myoglobin (myo antibody), and lactate dehydrogenase isoenzymes.

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