Abstract:

Objective To study the characteristics of interaction between the kaempferol(KF) and bovine serum albumin(BSA). Methods The quenching mechanism of the fluorescence of BSA by KF was studied with fluorescence spectra. The dynamic and static quenching constants were determined by the revised Stern-Volmer equation. The number of binding sites was calculated with double logarithmic equation and the main binding force was discussed by thermodynamic equations. The binding distance and energy transfer efficiency between donor(BSA) and acceptor(KF) were obtained based on Forster's nonradiative energy transfer theory. Results KF effectively quenched fluorescence of BSA via a combination of static and dynamic quenching processes. The binding constant KA was calculated to be in the order of 108, indicating a strong interaction between KF and BSA. The number of binding site is approximately equal to 2, the binding distance is 1.45 nm, the energy transfer efficiency is 0.73, and the binding force is mainly hydrophobic force. Conclusion KF effectively quenched the intrinsic fluorescence of BSA via combination of static and dynamic quenching mechanism, and the binding is mainly driven by the hydrophobic interaction.

Key words: kaempferol, bovine serum albumin, interaction, fluorescence spectrometry