Influence of Monovalent Cations on the Dipalmitoylphosphatidylcholine Phase Transitions

Beth Cunningham, Illinois Wesleyan University
L. J. Lis
P. J. Quinn

Abstract

The effect of different monovalent cations on the packing arrangements and phase behavior of dipalmitoylphosphatidylcholine (DPPC) in excess water and on the transition of the lamellar phase from the gel to liquid crystalline configuration has been investigated using differential scanning calorimetry and synchrotron radiation at the Daresbury Laboratory. Bilayers of DPPC in 1M KCI or water appear to undergo the same transition sequences without any change in the kinetics of phase induction. It was also observed that bilayers of DPPC in the presence of 1M LiCl produced no small angle x-ray scattering peaks characteristic of the P,, phase.