Thermodynamic Studies of Interaction Between Cationic Surfactants and Lysozyme Using Potentiometric Techniques

Abstract

The interaction between a homologous series of nalkyl trimethyl ammonium bromides and lysozyme was studied by a potentiometric method using a surfactant-selective electrode. The binding isotherms the interaction between a homologous series of nalkyl trimethyl ammonium bromides were measured for different conditions and show a concentration dependence attributable to aggregation of the lysozyme-surfactanl complexes. The binding isotherms arc discussed in terms of the binding potential concept of Wyman and are used to calculate an apparent Gibbs energy of binding per surfactant cation. The binding isotherms show that the C₁ decreases with increasing chain length of surfactant.

Key Words:

• Surfactant
• Cationic surfactant
• Lysozyme
• Binding isotherm
• Potentiometry