Radiation Effects with a Model Lipid Membrane

Abstract

A cell is described that permits a model phospholipid membrane and the two adjacent aqueous compartments to be irradiated with a collimated beam of X-rays. During a 2 h irradiation a marked increase in [H+] in the aqueous phases is observed. A protonmotive force, given by the H+ Nernst potential, is generated when one compartment only is irradiated or when both compartments separated by a membrane made structurally asymmetric by the adsorption of alamethicin, are irradiated equally.The results of irradiations in N2O, N2, and O2 indicate that the membrane scavenges the superoxide O2−. The effect is discussed in terms of a clearing field that is derived from the potential at the membrane interfaces.