The binding of Sodium n-dodecyl sulphate (SDS) to histone H3 was studied in the
pH range 3.2-10 by equilibrium dialysis at 27? and 3 7 ?c .T he binding data have been
used to obtain the Gibbs free energy of interaction using a theoretical model of the
Wyman binding potential; and the enthalpy of interaction from the temperature
dependence of theequilibriumconstantsfronr theVan't Hoff re1ation.The enthalpy of
interaction of H3 and SDS is exothermic in some buffer solutions which is in marked
contrast to other histone - SDS complexes, The entropy of initial interaction of H3 and
SDS is negative in some other buffer solutions with increasing binding of SDS, the
entropy becomes positive.