Application of the thermorheologically complex nonlinear Adam-Gibbs model for the glass transition to molecular motion in hydrated proteins

Abstract

The nonlinear thermorheologically complex Adam Gibbs (extended "Scherer-Hodge") model for the glass transition is applied to enthalpy relaxation data reported by Sartor, Mayer, and Johari for hydrated methemoglobin. A sensible range in values for the average localized activation energy is obtained (100-200 kJ mol-1). The standard deviation in the inferred Gaussian distribution of activation energies, computed from the reported KWW β-parameter, is ∼30% of the average, consistent with the suggestion that some relaxation processes in hydrated proteins have exceptionally low activation energies. © 2006 by the Biophysical Society.