title: Electron spin resonance study on the permeability of superoxide radicals in lipid bilayers and biological membranes.
abstract: The permeability of lipid bilayers and biological membranes to superoxide free radicals was examined by using superoxide dismutase (SOD)-loaded lipid vesicles and SOD-loaded erythrocyte ghosts. After exposing SOD lipid vesicles and SOD ghosts to enzymatically produced superoxide radicals and using spin-trapping and electron spin resonance (ESR) techniques, we found that SOD entrapped within erythrocyte ghosts effectively scavenges external O2.- while SOD inside the lipid bilayers has no effect. These results confirm that O2.- is able to cross through a biological plasma membrane but not across a pure lipid bilayer. The data provide instruction as to how and where anti-oxidant therapy is to be approached relative to the site of oxygen free radical production.
authors.affiliation: Department of Physiology, University of Alberta, Canada.
authors.forename: G D
authors.initials: GD
authors.lastname: Mao
authors.forename: M J
authors.initials: MJ
authors.lastname: Poznansky
mesh_terms: D002463:Cell Membrane Permeability / Q000502:physiology; D004578:Electron Spin Resonance Spectroscopy; D004910:Erythrocyte Membrane / Q000378:metabolism; D016166:Free Radical Scavengers; D005609:Free Radicals / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008051:Lipid Bilayers / Q000378:metabolism; D010539:Permeability; D013482:Superoxide Dismutase / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism*
chemical_list: D016166:Free Radical Scavengers; D005609:Free Radicals; D008051:Lipid Bilayers; D013481:Superoxides; D013482:Superoxide Dismutase