Electron spin resonance study on the permeability of superoxide radicals in lipid bilayers and biological membranes.
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.
Mao
G D
GD
Department of Physiology, University of Alberta, Canada.
Poznansky
M J
MJ
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*
D016166:Free Radical Scavengers; D005609:Free Radicals; D008051:Lipid Bilayers; D013481:Superoxides; D013482:Superoxide Dismutase