Interaction Studies of Sodium N-Dodecyl Sulphate and Protons to Nistone H1

The relationship between the binding of sodium n-dodecyl sulphate and protons to histone H1 has been investigated by equilibrium dialysis and titrimetry. The data cover the pH range 3.2-10 and surfactant concentrations up to 3.0×10-3 mol dm-3. A theoretical approach based on the binding potential concept of Wyman is presented and has been used to make estimates of the apparent Gibbs energies of binding of both protons and surfactant ions to the surfactant-histone H1 complexes. The average Gibbs energies of sodium n-dodecyl sulphate binding to H1 equal 28 to 18 kJ/mol for pH 3.2 to 10 respectively.