Table 4. Thermodynamic Parameters by Isothermal Titration Calorimetrya.
| analyte | Kd (μM) | ΔG(kcal/mol) | ΔH(kcal/mol) | ΔS(cal/mol/deg) |
|---|---|---|---|---|
| QHCl | 11 ± 1 | –6.8 ± 0.1 | –5.1 ± 0.1 | 5.53 |
| PHCl | 8.8 ± 1.6 | –6.9 ± 0.1 | –3.0 ± 0.1 | 13.2 |
a
Kd and ΔH were obtained from the fitted curve according to a model for one set of sites. ΔS and ΔG were obtained from eq 1. QHCI, quinine hydrochloride; PHCI, promethazine hydrochloride; Kd, dissociation constant; ΔG, free energy change of binding; ΔH, enthalpy change of binding; ΔS, entropy change of binding.