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Spin trapping of lipid-derived radicals in liposomes. Biochim Biophys Acta 1989 Aug 18;992(2):230-5

Date

08/18/1989

Pubmed ID

2547451

DOI

10.1016/0304-4165(89)90015-9

Scopus ID

2-s2.0-0024346387 (requires institutional sign-in at Scopus site)   19 Citations

Abstract

Electron-spin resonance-spin trapping has been used to detect lipid-derived radicals in liposomes. Using the lipid-soluble spin trap 2-methyl-nitrosopropane (MNP), we have detected both the lipid and hydrogen-atom spin adducts in liposomes composed of a fully saturated phospholipid (dimyristoylphosphatidylcholine, DMPC) with various mol fractions of unsaturated phospholipid (1-palmitoyl-2-arachidonoylphosphatidylcholine, PAPC) or fatty acid (arachidonic acid, AA). The lipid-derived spin adduct formed during autoxidation of liposomes was separated by thin-layer chromatography and found to co-migrate with the product(s) formed by direct addition of MNP to the corresponding unsaturated lipid or fatty acid. Both the MNP-PAPC and MNP-AA spin adducts showed some restriction of rotational motion when in the liposome bilayer (rotational correlation times 0.72 and 0.69.10(-9) s, respectively), and nitrogen hyperfine coupling constants (14.94-14.96 G) consistent with a hydrophobic localization. Radical versus non-radical mechanisms of spin adduct formation during liposome autoxidation were separated using alpha-tocopherol as a radical scavenger. The utility of nitroso spin traps in trapping of radicals in liposomes is discussed.

Author List

Feix JB, Kalyanaraman B

Authors

Jimmy B. Feix PhD Professor in the Biophysics department at Medical College of Wisconsin
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Chromatography, Thin Layer
Electron Spin Resonance Spectroscopy
Free Radicals
Lipid Metabolism
Lipids
Liposomes
Nitroso Compounds
Oxygen Consumption
Phospholipid Ethers
Spin Labels
Structure-Activity Relationship
Vitamin E