Superoxide dismutase inhibits lipid peroxidation in micelles.
Superoxide dismutase (SOD) taken in minor concentrations (a few U/ml) displays a pronounced inhibiting effect on the chain oxidation of methyl linoleate and methyl linolenate (but not methyl oleate) induced by 2,2'-azobis(2-amidinopropan) dihydrochloride (AAPH) in micellar solutions of sodium dodecyl sulfate and Triton X-100 in phosphate buffer, pH 7.40, at 37.0 degrees C. The inhibition is evidently caused by purging the system from O(2)*(-). The latter suggests the formation of O(2)*(-) (HO(2)* in the course of peroxidation, most likely, via beta-decay of lipid peroxy radical (LO(2)*. Thermodynamic estimations verify a rather high probability of beta-decay of LO(2)* produced from polyunsaturated fatty acids by contrast to that produced from saturated and monoenic fatty acids. It is speculated that O(2)*(-) (HO(2)*, being an amphiphilic, reactive and highly mobile species, participates in intermicellar (interliposomal) transfer of free valence during lipid peroxidation in microheterogeneous systems.
Roginsky
V
V
N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Kosygin St. 4, 117977, Moscow, Russia. rogin@postman.ru
Barsukova
T
T
D005231:Fatty Acids, Unsaturated / Q000737:chemistry; D015227:Lipid Peroxidation; D008823:Micelles; D013482:Superoxide Dismutase / Q000737:chemistry*; D013501:Surface-Active Agents; D013816:Thermodynamics
D005231:Fatty Acids, Unsaturated; D008823:Micelles; D013501:Surface-Active Agents; D013482:Superoxide Dismutase