Fluorescence spectroscopy study on the interaction between Gossypol and bovine serum albumin

The characteristics of the binding reaction of Gossypol with bovine serum albumin (BSA) were studied by fluorescence spectroscopy. The experimental results showed that Gossypol caused the fluorescence quenching of BSA through a static quenching procedure. The binding constant KA of Gossypol with BSA at 293 and 303 K were obtained as 1.51 × 106 and 1.15 × 106 L mol−1, respectively. There is one binding site between Gossypol and BSA. According to the thermodynamic parameters, it is more likely that hydrophobic and electrostatic interactions are involved in the binding process. Based on the Förster non-radiation energy transfer theory, the average binding distance between the donor (BSA) and the acceptor (Gossypol) was obtained (r = 2.18 nm). The effect of Gossypol on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.