Thermodynamic model for isobaric heat capacities associated with cold and warm thermal denaturation of proteins

Abstract

The dependence on temperature T of the standard chemical potential of a given solute j in aqueous solution, µ^o_j(aq) is expressed as a function of the difference (T–θ), where θ is a reference temperature. The resulting equation is applied to each solute contributing to a chemical equilibrium, X(aq)⇔ Y(aq) in order to probe the consequent dependence on T of the isobaric heat capacity C_p(aq) of the aqueous solution. Conditions are identified under which a plot of C_p(aq) against T shows none, one or two maxima. The analysis identifies conditions under which differential scanning calorimetry will provide evidence, for example, of warm and cold thermal denaturation of proteins.