Effect of neutral salts on the formation and dissociation of protein aggregates

Abstract

A theoretical framework is presented for the treatment of solvent-mediated behavior observed with polymerizing systems. It has been found that the surface tension and the bulk dielectric constant of the medium play a major role in determining the energetics of the polymerization or depolymerization process. The effect of salt is accounted for by specific binding, by electrostatic effects, which are treated on the basis of the Debye-Huckel theory, and by salt-induced changes in the surface tension. Literature data on the effect of various salts on the depolymerization of apo-D(—)-β-hydroxybutyrate dehydrogenase observed chromatographically, on the actin G-F equilibrium, and in flagellin polymerization show the theoretically predicted behavior. The influence of organic solvents in the medium can be treated in a similar fashion as demonstrated by observed dependence of the activation energy of actin-F polymerization on the concentration of ethanol.