Influence of urea on thermal denaturation of lysozyme investigated by optical and dielectric spectroscopies

Abstract

Different structural probes following the unfolding process of a protein may evidence the existence of stable intermediates from the differences in the unfolding curves. In this work, we analyze the thermal unfolding of chicken egg lysozyme in the presence of 8 M urea at pH 5 combining dielectric spectroscopy in the radiofrequency region, UV absorbance and circular dichroism in the far and near UV regions. The data are consistent with a two-state model of unfolding equilibrium and do not provide support for the presence of a significantly populated intermediate state.