Interaction of zearalenone with bovine serum albumin as determined by fluorescence quenching

The major aim of this study was to examine the binding of zearalenone (ZEN) to bovine serum albumin (BSA) by measuring the quenching of the intrinsic fluorescence of the protein under aqueous conditions. The results suggest that ZEN has a strong ability to quench the intrinsic fluorescence of BSA through a static mechanism. The hydrophobicity of the microenvironment around the tyrosine (Tyr) residues in BSA was increased in the presence of ZEN. The quenching constants, ratio of protein with ZEN, and thermodynamic parameters were determined. The collaborative action of hydrophobic and electrostatic interactions was involved in the binding process and the formation of the complex was mainly enthalpy-driven. The average binding distance between ZEN and BSA was calculated to be 2.20 nm. This is much closer in magnitude than the distance reported for the binding of most toxins to HSA and most pharmaceuticals to BSA, indicating a strong affinity.