Molecular thermodynamic properties of protein solutions from partial specific volumes

Abstract

Partial spec$c uolumes at 25°C are reported for a-chymotrypsinogen in aqueous solutions containing NaCI, citrate, and/or polyethylene glycol (PEG)

Recent Applications of Kirkwood–Buff Theory to Biological Systems

“…Early theoretical progress included the equations presented by Ben-Naim for multicomponent solutions which are also applicable to biological systems at very low cosolvent concentrations [62]. In addition, Pjura et al used KB theory to interpret experimental data concerning partial specific volumes of proteins [97], and Hirata and coworkers have applied KB theory to understand changes in protein volumes on denaturation [98,99]. Apart from these early studies, the application of KB theory to biological systems was rather limited.…”

Contribution of protein charge to partitioning in aqueous two-phase systems

“…The differences in charge and charge distribution among the T4 lysozymes changes both protein-protein and protein-polymer interactions. Positive values of the second virial coefficient indicate that the average force between the two molecules is repulsive, while negative values indicate an attractive mean force between the two molecules (Coen et al, 1995(Coen et al, , 1996Forciniti and Hall, 1990;Haynes et al, 1989Haynes et al, , 1991Pjura et al, 1995). The expectation discussed above, that the addition of a charged tail has increased the dipole-dipole and charge-dipole attractions, is seen in the lower values of A ij between the fusions and the two polymers compared to those between the corresponding point mutants and the same two polymers (Coen et al, 1995(Coen et al, , 1996.…”

Effect of protein and solution properties on the donnan effect during the ultrafiltration of proteins

“…The Donnan effect will be significant ( x > 1.1 or x < 0.9) when the absolute value of charge‐molality ratio I is greater than 0.1. The retentate molalities can be converted to concentration, C (g/L), by accounting for the excluded volume of the protein: where the solvent concentration c (kg/L) can be calculated from where c P is the protein concentration (g/mL), v P is the protein partial specific volume (mL/g), which typically ranges from 0.7 to 0.810, 11, and ρ is the density of water in kg/L. A protein partial specific volume of 0.75 mL/g, which was close to the value obtained from the measured density of a concentrated antibody solution, was used in this study.…”