Linda C. Rogers, Ph.D.
Troponins are a family of proteins found in skeletal and heart (cardiac) muscle fibers that produce muscular contraction. Troponin T (TnT) and I (TnI) molecules have amino acid sequences that are found only in cardiac tissue. With damage to heart muscle cells, cardiac-specific troponin is released into the bloodstream. Thus, cardiac troponins (troponin I and T) are very sensitive and specific indicators of damage to the myocardium.