Studies on Unfolding of Bovine Serum Albumins Induced by Urea in the Presence of Denaturant by Fluorescence Phase Diagram

The unfolding of bovine serum albumins(BSA) induced by urea in the presence of denaturant was studied by fluorescence phase diagram.Experimental results showed that the BSA induced by urea were directly unfolded from native state to unfolded state in the presence of denaturant,2-mercaptoethanol and no folded intermediates were detected.It was found that the unfolding procedure conformed to a typical two-state model.However,a partially folded BSA intermediate could be detected in the absence of 2-mercaptoethanol at urea concentration varying from 0 mol/L to 0.7 mol/L,and the BSA would transform totally from the intermediate state to unfolded state at urea concentration varying from 0.7 mol/L to 8.0 mol/L.At this moment,the denaturation process of BSA conformed to a typical three-state model.