Effects of Temperature and Ions on Binding Dihydromyricetin to Bovine Serum Albumin by Spectroscopic Method

ABSTRACT

The interaction of dihydromyricetin (DMY) and bovine serum albumin (BSA) in solution was investigated by fluorescence, synchronous fluorescence, and ultraviolet (UV) spectra. These results revealed that DMY quenches the fluorescence of BSA by forming the DMY–BSA complex. The number of binding sites (n), binding constant (K _a ), and thermodynamic parameter (ΔG, ΔH, ΔS) were calculated. The primary binding forces between DMY and BSA were found to be the electrostatic force and hydrophobic interaction. The binding distance (r) between the donor (BSA) and acceptor (DMY) was determined as 3.43 nm based on Förster's theory. The effect of metal ions (Ni²⁺, K⁺, Cu²⁺, and Co²⁺) on the binding constant of DMY–BSA complex was also investigated. The effect of DMY on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy and UV-Vis absorption spectroscopy.

KEYWORDS:

• bovine serum albumin
• dihydromyricetin
• fluorescence spectroscopy
• interaction
• ion

ACKNOWLEDGMENT

The authors are grateful for financial support from the National Natural Science Foundation of China (Grant Nos. 20776162, 20775092, and 20805058).