GdnHCl-induced denaturation curves of EGFP at pH 8, in the absence of any additive (open circles) and in the presence of various additives such as 0.85 M KCl (open squares), 0.7 M KNO3 open triangles), 0.17 M K2SO4 (open diamonds), and 18% glycerol of viscosity 1.61 cP (open hexagons), obtained by EGFP fluorescence measurements at 520 nm.