Redistribution of the spin-labeled phospholipid analogue SL-PS in resealed erythrocyte ghosts at neutral and acidic pH of the suspension medium at 4°C. Resealed ghosts were prepared by hypotonic lysis as described by Schwoch and Passow.40 After incorporation of SL-PS, the redistribution kinetics were monitored by the back-exchange of analogues on the outer leaflet to BSA (see the Materials and Methods). pH 5.8 (▿), pH 7.4 (▾). Curves were fitted by nonlinear regression to a monoexponential function.