Abstract
Some recent developments of the thermodynamic studies on the multi-state thermal transitions of globular proteins are reviewed. Enphasis has been placed to the statistical mechanical basis and new methods of the scanning calorimetry data analysis for the multi-state system. In the analyses, a thermodynamic state is defined as an ensemble of the microstates of the system, assuming the heat capacity function and two integral constants. Upon these assumptions, the multi-state system can be analyzed by deconvolution method even when the system includes self-dissociation/association process, using the relation between the partition function (or molar fraction function) and the enthalpy function. The obtained thermodynamic parameters are refined by non-linear least squares fitting. By the methods, the thermal transitions of porcine pepsinogen at various pH values are analyzed to be four-state transitions, and the thermal transition of Vibrio parahaemolyticus hemolysin at pH7.0 are estimated to be three-state transition including dimer-monomer equilibrium.
