Table 2.
The characteristics of isothermal titration calorimetry (ITC) experiments for tafamidis binding to different TTR mutants.
| TTR protein | Ka1 (M−1) | ΔH1 (kcal/mol) | Ka2 (M−1) | ΔH2 (kcal/mol) | Kd1 (nmol/L) | Kd2 (nmol/L) |
|---|---|---|---|---|---|---|
| WT | 4.2 × 108 | −6.48 | 3.0 × 106 | −6.8 | 2.4 | 333.3 |
| A97S | 3.5 × 108 | −5.95 | 3.8 × 106 | −6.6 | 2.9 | 263.2 |
| V30M | 6.5 × 106 | −7.2 | 1.6 × 106 | −6.4 | 153.8 | 625 |
| L55P | 9 × 106 | −8.584 | 1.2 × 106 | −5.12 | 111 | 833 |
The binding isotherm were fitted with a model of two interacting sites exhibiting negative cooperativity to obtain the binding parameters, including dissociation constants, Kd1 and Kd2, and enthalpy, ΔH1 and ΔH2. Dissociation constants of tafamidis:WT‐TTR, tafamidis:A97S‐TTR, tafamidis:V30M‐TTR and tafamidis:L55P‐TTR were determined by finding the best fitted parameters to the experimental thermograms. The binding constants of tafamidis binding Kd1 and Kd2 were determined as the inverse of the association constants. All ITC experiments were performed at least three times in order to obtain the statistical results.