Dual Effect of Secondary Solutes on Binding Equilibria: Contributions from Solute-Reactant Interactions and Solute-Water Interactions.

ABSTRACT: This study examines the role of water in binding equilibria with a special focus on secondary solutes (cosolutes) that influence the equilibrium but are not constituents of the final product. Using a thermodynamic framework that includes an explicit term for the release of water molecules upon binding, this investigation reveals how solutes may alter equilibria by changing the activity of the reactants, reflected in ΔG°^(obs), and by changing the chemical potential of the solvent, reflected in ΔG^S. The framework is applied to four experimental binding systems that differ in the degree of electrostatic contributions. The model systems include the chelation of Ca²⁺ by EDTA and three host-guest reactions; the pairings of p-sulfonatocalix[4]

SUBMITTER: Eggers DK 

PROVIDER: S-EPMC10795149 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature