Investigation of the interactions of lysozyme and trypsin with biphenol A using spectroscopic methods

The interaction between bisphenol A (BPA) and lysozyme (or trypsin) was investigated by UV–vis absorption, fluorescence, synchronous fluorescence, and three-dimensional fluorescence spectra techniques under physiological pH 7.40. BPA effectively quenched the intrinsic fluorescence of lysozyme and trypsin via static quenching. H-bonds and van der Waals interactions played a major role in stabilizing the BPA–proteinase complex. The distance r between donor and acceptor was obtained to be 1.65 and 2.26 nm for BPA–lysozyme and BPA–trypsin complexes, respectively. The effect of BPA on the conformation of lysozyme and trypsin was analyzed using synchronous fluorescence and three-dimensional fluorescence spectra.