Thermochemical analysis of Aspergillus niger catalase and sodium n-dodecyl sulphate interaction

Abstract

The binding of sodium n-dodecyl sulphate (SDS) to Aspergillus niger catalase was studied in the pH range 3.2–10 by equilibrium dialysis at 25 and 37° C. The binding data have been used to obtain the thermodynamic parameters of interaction using a theoretical model of the Wyman binding potential and van't Hoff relation. The theoretical enthalpy (Δ H VH) of interaction between Aspergillus niger catalase and SDS was compared with the experimental enthalpy (Δ H cal) at various pH values between 3.2 and 10. A large value of Δ H VH/Δ H Cal is obtained which is consistent with activation of Aspergillus niger catalase and SDS complexes at pH 6.4.