Troponin

Troponin I is a 24kDa protein and is part of a
complex, called Troponin complex, that regulates the
calcium-modulate interaction between actin and
myosin in the striated muscle; this complex is an
heterodimer consisting of Troponin C, I and T;
Troponin I is the inhibitory subunit of this complex.
Troponin complex is tightly bound to the contractile
apparatus, but many studies shows that the Troponin
I is released into the blood circulation in case of
myocardial damage, such as in AMI (Acute
Myocardial Infarction), where the myofibril is seriously
damaged. The presence of Troponin I in the
circulation can be detected for many days after AMI,
thus the detection of Troponin levels in blood fluids is
an excellent biomarker for myocardial damage.
It should be note that in case of marathon runners or
other skeletal injury the Troponin I has not been found
in circulation, thus it is a very specific marker for AMI.