THERMOMETRIC TITRATION STUDIES OF THE INTERACTION OF BLOCK POLYPEPTIDES WITH SURFACTANTS

The interactions between surfactants and block polypeptides were investigated by titration calorimetry and CD. The polypeptides exhibited signs of an interaction only with surfactants bearing a charge opposite to the charge on the polymer. The stoichiometry of the resulting complex was determined to be approximately equal to the polymer net charge. In general, a decrease in helical content accompanied the interaction between the block polypeptides and the surfactants. Both positive and negative enthalpy changes were noted, depending on the heat of micelle formation. None of the thermal effects noted were preceded by polymer unfolding, as is characteristic of the interaction between surfactants and typical globular proteins. Copyright © 1979 John Wiley & Sons, Inc.