The interaction between myricetin and bovine serum albumin (BSA) was investigated by UV absorption spectroscopy, fluorescence spectroscopy, red edge excitation shift (REES) method, circular dichroism (CD) and molecular modeling together to explore the mechanism of interaction under simulated physiological condition. The result of molecular modeling indicated that myricetin can bind with BSA in the hydrophobic pocket of sub-domain ⅡA with hydrophobic force and hydrogen bonding as the main acting force. The fluorescence quenching of BSA by myricetin was employed to observe the quenching mechanism that proved to be a static one. Binding constant (K_a) and binding sites (n) at different temperatures were all calculated, respectively. The results of corresponding thermodynamic parameters as well as binding distance between BSA and myricetin were obtained and proved to agree with that from the molecular modeling. The transformation of micro-environment of Trp in BSA was observed by the spectra of UV absorption, synchronous fluorescence and REES method, while the spectrum of CD was employed to research the change of the secondary structure of BSA quantitatively through the assay of α-helix.

Key words: molecular modeling, spectroscopy, myricetin, BSA, interaction