THERMODYNAMIC STUDIES ON THE INTERACTION BETWEEN DODECYL TRIMETHYL AMMONIUM BROMIDE AND HISTONE H A

Abstract

The thermodynamic parameters of interaction between calf thymus histone
H A and dodecyl trimethyl ammonium bromide (DTAB), a cationic surfactant,
in aqueous solutions of pH 3.2, 6.4 and 10.0 were measured over a wide range
of DTAB concentrations by equilibrium dialysis at 27°C and 37°C and are
discussed. The data are used to determine the free energy from the Wyman
binding potential theoretical model, and the enthalp y of interaction from the
temperature dependence of the equilibrium constants using the van't Hoff relation.
The data obtained for H A-DTAB are compared with the corresponding
data for H A and sodium n-dodecyl sulphate (SDS) complexes. The difference
between the cationic and anionic surfactants interaction in regard to histone
H A is discussed