Assessing the potential toxic effect of one persistent organic pollutant: Non-covalent interaction of dicofol with the enzyme trypsin

Because of the widespread concern that persistent organic pollutants (POPs) may be adversely affecting the health of humans, reliable assessing their toxic effects is urgently needed. We selectively study the interaction between dicofol (DCF) and trypsin by steady state and time resolved fluorescence quenching measurements and UV-visible absorption spectroscopy under physiological conditions as well as applying molecular docking method to establish the interaction model. The fluorescence results indicate DCF can spontaneously form a complex with trypsin mainly by hydrogen bond with only one binding site, which had been validated in molecular docking. The conformational change of trypsin was proved by UV-visible absorption and synchronous fluorescence spectroscopy indicating a red shift of carbonyl absorption peak. All the results indicated DCF had potential toxic effects on both the structure and activity of the enzyme trypsin and the effects enhanced with the increasing concentration of DCF. (C) 2011 Elsevier B.V. All rights reserved.