 Given that the fractions must sum to one and their ratio must be given by the Boltzmann factor, we have

Protein stabilities are typically found to vary linearly with the denaturant concentration.A number of models have been proposed to explain this observation prominent among them being the denaturant binding model, solvent-exchange model (both by John Schellman) and the Linear Extrapolation Model (LEM; by Nick Pace).All of the models assume that only two thermodynamic states are populated/de-populated upon denaturation.