Food additive dye–lysozyme complexation: Determination of binding constants and binding sites by fluorescence spectroscopy and modeling methods

Abstract

The interaction mechanisms of QY with lysozyme were investigated using multispectral and molecular docking methods in the current study. Quinoline yellow (QY) is a synthetic dye that is widely used in the food industry. The interaction of QY with this proteinase was studied using fluorescence spectroscopy. The fluorescence quenching results demonstrated that QY could quench this proteinase's intrinsic fluorescence using a static quenching procedure. Through hydrogen bonding and van der Waals interactions, QY binds to lysozyme. The binding constant (Ka) and the number of binding sites (n) for this binding interaction were determined using associated fluorescence quenching data. The presence of QY dye reduced enzyme activity, according to kinetic technique analysis. The CD results confirmed the protein's conformational changes during the complexation process. Aside from the experimental studies, molecular docking revealed the precise binding location of QY within the lysozyme enzyme structure. Molecular dynamics simulation was also used to assess the stability of the lysozyme-QY complex.