Binding interaction between bovine serum albumin and chicoric acid, a food functional component

Abstract

Fuorescence, FTIR and UV-Vis absorption spectroscopy were used to explore the binding between chicoric acid and Bovine Serum Albumin (BSA). Binding characteristics at various levels of temperature have been calculated. The results indicated that chicoric acid statically quenched the intrinsic fluorescence of BSA. The binding constants (Ka) were 4.14×105 L mol-1 at 273K and 4.29×106 L mol-1 at 298 k. The numbers of binding sites between chicoric acid and BSA were both approximately equal to 1 at the two temperatures. Furthermore, the binding distance between chicoric acid and BSA was 2.69 nm which was calculated according to the Forster’s resonance energy transfer. Thermodynamic parameters suggested that BSA bind chicoric acid spontaneously mainly via hydrophobic interaction. Results demonstrated that the conformation and microenvironment of BSA were changed after binding with chicoric acid. Moreover, chicoric acid showed stronger binding with tryptophan (Trp) residue than with tyrosine (Tyr) residue. Our results can provide scientific basis for studying availability and distribution of chicoric acid.