A comparison of the activation energy of viscous flow for hen egg-white lysozyme obtained on the basis of different models of viscosity for glass-forming liquids

Abstract

The paper presents the results of viscosity determinations on aqueous solutions of hen egg-white lysozyme at a wide range of concentrations and at temperatures ranging from 5 o C to 55 o C. On the basis of these measurements and different models of viscosity for glass-forming liquids, the activation energy of viscous flow for solutions and the studied protein, at different temperatures, was calculated. The analysis of the results obtained shows that the activation energy monotonically decreases with increasing temperature both for solutions and the studied protein. The numerical values of the activation energy for lysozyme, calculated on the basis of discussed models, are very similar in the range of temperatures from 5 o C to 35 o C.

Conformational Flexibility and Self-Association of Fibrinogen in Concentrated Solutions

“…The measurements have shown the batch-and species-independence; the bovine and human Fg preparations gave very similar results. The extracted value of activation energy for Fg self-diffusion, E d = 21.3 kJ/mol in 1.42 mg/mL Fg solution, agrees well with 18.0−20.4 kJ/mol determined earlier for water in a protein (lysozyme) solution 36 at the equivalent protein concentrations. For comparison, the activation energy for self-diffusion of pure water is E W = 17.8 kJ/mol.…”

“…In the Rouse model (iii), the beads roughly represent the distal and central globular parts connected by the coiled-coils. In our previous study of the Fg molecule in solution, we showed that the coiled-coil connectors behave as entropic springs. ,, In the Rouse model, each bead is characterized by its own friction (see eq ), and water molecules drain freely through a moving protein chain. Because the Rouse model ignores hydrodynamic interactions of a biopolymer chain with solvent and neglects the intrinsic viscosity [ η ], a disagreement between the model predictions and the crystal structure would imply the importance of hydrodynamic coupling.…”

The Glass Transition Temperature and Temperature Dependence of Activation Energy of Viscous Flow of Ovalbumin

“…This equation gives the functional dependence of the viscosity on temperature and can be used for obtaining the functional dependence of the activation energy of viscous flow on temperature. After inserting the equation (1) into the definition (3), differentiation and simple transformations we obtain the following expression for the activation energy of the solution (Monkos, 2011a):…”

“…The numerical values of the parameters F s (c) and T o,s (c) , which are important in the further part of this work, for all measured concentrations of ovalbumin, are gathered in Table 1. As in the Avramov's model function from relation (6) can insert to the definition (3) and obtain the functional dependence of the activation energy of the solution (Monkos, 2011a):…”

“…The insertion of the function from formula (8) to the definition (3) gives the following equation for the activation energy of a solution (Monkos, 2011a):…”