Statistical thermodynamics of molecules with multiple adsorption states: application to protein adsorption

Abstract

The statistical thermodynamics of molecules with multiple adsorption states has been studied using a lattice model. The thermodynamic functions calculated for a system characterized by two adsorption states are applied to describe the adsorption of antifreeze proteins onto an ice crystal. The theoretical formalism reproduces the classical Langmuir equation (one-state limit), leads to the exact statistical thermodynamics of molecules adsorbed in one dimension with n dierent adsorption states, and provides a close approximation for two-dimensional systems. Comparisons with Monte Carlo simulations and analytical data derived from kinetic arguments are performed in order to test the validity of the theoretical model. The resulting framework represents a qualitative advance with respect to the existing development on multistate adsorption thermodynamics and seems to be a promising way toward a more accurate description of the adsorption thermodynamics of structurally diverse proteins.