Abstract
The kinetics of Pr3+ transport by the ionophores alamethicin 30 and A23187 across unilamellar phospho-lipid vesicular membranes has been compared by following the time-dependent changes in the 1H-NMR spectrum of the vesicles. The measured rates of transport allow stoichiometries of the transporting species to be deduced which are consistent with channel- and carrier-mediated mechanisms respectively. The method provides a useful complement to planar bilayer conductivity studies of these systems.