Troponin T Type 2, Cardiac (TNNT2) is one of three troponin isoforms found in the tropomyosin-troponin complex. This complex is responsible for the calcium sensitivity of the contractile apparatus in the muscle. Cardiac Troponin T is used as a biological marker for cardiomyocytes and its level in serum is frequently used as an indicator of myocardial cell injury. Besides, Troponin I Type 3, Cardiac (TNNI3) has been identified as an interactor of TNNT2, thus a binding ELISA assay was conducted to detect the interaction of recombinant human TNNT2 and recombinant human TNNTI3. Briefly, TNNT2 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100μl were then transferred to TNNI3-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-TNNT2 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50μL stop solution to the wells and read at 450/630nm immediately. The binding activity of TNNT2 and TNNI3 was shown in Figure 1, and this effect was in a dose dependent manner.