Abstract

Comparative studies on the interaction between metronidazole and lysozyme by fluorescence quenching spectroscopy and synchronous fluorescence spectroscopy

Author(s): Rong Han, Baosheng Liu, Gaixia Li, Qiuju Zhang

Under simulative physiological conditions, the interactions between lysozyme(LYSO) and metronidazole(MET) at different temperatures (298, 310 and 318K)were studied using fluorescence quenching and synchronous fluorescence spectroscopy respectively. The results indicated that MET quenched the intrinsic fluorescence of LYSO via a static quenching procedure. The binding constants obtained from above method were of the same order ofmagnitude and very similar; the number of binding site in the interaction was closed to 1. The negative enthalpy changes and positive entropy changes implied that electrostatic interaction might play a main role in the interaction betweenMET and LYSO. Onthe basis of the Förster theory of the resonance energy transfer, the binding distance between LYSO and MET was less than 7 nm. In addition, the conclusions obtained from two methods using the same equation were consistent. It indicated that the synchronous fluorescence spectrometry could be used to study the binding mechanism between drug and protein, and was a useful supplementto the fluorescence quenching method.