Development of a new EPR spin trap, DOD-8C (N-[4-dodecyloxy-2-(7'-carboxyhept-1'-yloxy) benzylidene]-N-tert-butylamine N-oxide), for the trapping of lipid radicals at a predetermined depth within biological membranes

作者：Hay A; Burkitt MJ^*; Jones CM; Hartley RC

来源：Archives of Biochemistry and Biophysics, 2005, 435(2): 336-346.

DOI：10.1016/j.abb.2004.12.030

• electron paramagnetic resonance
• spin trapping
• lipid peroxidation
• lipid radicals
• tert-butylhydroperoxide
• copper-1,10-phenanthroline

We report on the development of the first member of a new family of EPR spin-trapping agents designed to trap radicals at a predetermined depth within biological membranes. By analogy to the use of nitroxide spin labels to 'report' on the environment at specific depths within biological membranes, we set out to prepare similar reporter molecules, but With a nitrone in place of the nitroxide function. The prototype compounds were tested in a model system consisting of large unilamellar vesicles exposed to a copper-dependent radical generating system. This entailed the reduction of tert-butylhydroperoxide to the tert-butoxyl radical ('BuO.) by a membrane-permeable Cu-1 complex, which was generated in situ by reduction of the Cull complex by ascorbate. To assist in the identification of the radicals detected, preliminary studies were performed in methanolic solution, where the major radical trapped was shown to be(.)CH(2)OH, resulting from H-atom abstraction from the alcohol by 'BuO.. This conclusion was shown to be in agreement with predictions based on chemical kinetics, which were then used to support the proposal that the primary species trapped in the lipid vesicles were radicals derived from membrane fatty acids. This molecule represents the first of a new generation of spin traps which, through modification, can be used to position the radical-trapping nitrone moiety at chosen depths within biological membranes.

• 出版日期2005-3-15