Thermodynamics of the Binding of Lysozyme to a Dendritic Polyelectrolyte: Electrostatics Versus Hydration.

ABSTRACT: The interaction between dendritic polyglycerol sulfate (dPGS) of the second generation and lysozyme was studied by isothermal titration calorimetry (ITC) at different temperatures and salt concentrations. Analysis by ITC showed that 2-3 lysozyme molecules were bound to each dPGS. The resulting binding constant K _b and the Gibbs free energy ΔG ^o decreased markedly with increasing salt concentration but were nearly independent of temperature. The salt dependence of K _b led to the conclusion that ca. 3 counterions bound to dPGS were released upon complex formation. The gain in entropy ΔG _ci by this counterion-release scales logarithmically with salt concentration and is the main driving force for binding. The temperature

SUBMITTER: Ran Q 

PROVIDER: S-EPMC6644519 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature