The binding of adriamycin (ADR) and its iron complex with
human serum albumin (HSA) was studied by the resonant mirror biosensor
(IAsys) at five different
temperatures in the range from 15 to 37 ℃. The equilibrium constants were obtained under different temperatures. The results showed that the bind- ing reaction was enhanced with temperature rising, and the affinity of ADR-Fe(III) with HSA was higher than that of ADR. The thermodynamic parameters were measured by the integrated Van’t Hoff equation. The ?H0 and T0?S0 at the reference temperature 25 ℃ (T0) were 25.11 and 57.01 kJ?mol-1 respectively. The positive ?S could be more than to compensate the negative ?S due to other interactions and the positive ?H. The large positive ?H and T?S reflected the complexity of the binding mechanism between ADR and HSA. The binding reaction was driven largely by the entropy change. The energy changes could be mainly assigned to solvent entropy contribution. Therefore, the binding process was governed primarily by hydrophobic force, and the water molecules played a major role in the binding reaction.