Table 3.
Effect of temperature on the binding constant Ka and the thermodynamic parameters (ΔG, ΔH and ΔS) of the interaction of compounds 1 to 5 with BSA.
| Compound | Temperature (T) (K) |
1/T/x 10−3 (K⁻1) | Ka/M−1 | ln Ka | ΔG (KJmol−1) | ΔH/(KJmol−1) | ΔS/(Jmol−1K−1) |
|---|---|---|---|---|---|---|---|
| 1 | 298 | 3.356 | 5.47 × 103 | 8.61 | -21.68 | -109.5 | -294.7 |
| 308 | 3.300 | 3.25 × 103 | 8.09 | -18.73 | |||
| 313 | 3.194 | 4.61 × 102 | 6.13 | -17.26 | |||
| 2 | 298 | 3.356 | 2.25 × 105 | 12.32 | -30.60 | -325.26 | -988.78 |
| 308 | 3.300 | 3.58 × 103 | 8.18 | -20.76 | |||
| 313 | 3.194 | 4.05 × 102 | 6.00 | -15.77 | |||
| 3 | 298 | 3.356 | 5.88 × 108 | 20.19 | -49.38 | -646.07 | -2002.29 |
| 308 | 3.300 | 4.62 × 104 | 10.74 | -29.36 | |||
| 313 | 3.194 | 2.79 × 103 | 7.93 | -19.35 | |||
| 4 | 298 | 3.356 | 6.90 × 106 | 13.45 | -32.08 | -84.02 | -174.29 |
| 308 | 3.300 | 1.14 × 105 | 11.64 | -30.34 | |||
| 313 | 3.194 | 1.07 × 105 | 11.58 | -29.47 | |||
| 5 | 298 | 3.356 | 1.02 × 103 | 6.93 | -16.18 | -97.23 | -271.98 |
| 308 | 3.300 | 5.70 × 101 | 4.04 | -13.46 | |||
| 313 | 3.194 | 2.93 × 102 | 5.48 | -12.10 |
ΔH: enthalpy change, ΔS: entropy change, ΔG: free energy.