Abstract:

The binding reaction of caffeic acid with bovine serum albumin (BSA) was studied using fluorescence spectroscopy. Caffeic acid quenched the fluorescence of BSA through a static process. The primary binding pattern between caffeic acid and BSA included electrostatic and hydrophobic interaction, and the latter was identified to be the main force under physiological condition. It was found that caffeic acid was located near the Tyr residue region of site I in BSA by competing binding experiment using warfarin and ibuprofen as site markers by fluorescence spectra. The distance between the donor (BSA) and receptor (caffeic acid), r0, was obtained to be 3.64 nm according to Forster's non-radiative energy transfer theory. In addition, the effect of caffeic acid on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.

Key words: caffeic acid, bovine serum albumin, interaction, competitive binding experiment