Studies on the interaction between docetaxel and human hemoglobin by spectroscopic analysis and molecular docking

The binding reaction between docetaxel (DTX) and human hemoglobin (HHb) was investigated systematically with various spectroscopic methods including fluorescence quenching technique, ultraviolet (UV)–vis absorption, synchronous fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy. Analysis of fluorescence data showed that the quenching mechanism was the dynamic quenching and each protein had only one binding site for the drug. Two thermodynamic parameters, the enthalpy change and the entropy change were calculated to be 9.18 kJ mol−1 and 116 J mol−1 K−1, respectively, which suggested that hydrophobic interaction played a major role in the binding reaction. The results from different spectroscopic methods also showed that DTX could induce conformational changes of HHb. The molecular docking simulation demonstrated that DTX was located in the central cavity of HHb.