Author/Authors
H. Sprinz، نويسنده , , J. Schwinn، نويسنده , , S. Naumov، نويسنده , , O. Brede، نويسنده ,
DocumentNumber
1601535
Title Of Article
Mechanism of thiyl radical-catalyzed isomerization of unsaturated fatty acid residues in homogeneous solution and in liposomes
شماره ركورد
11904
Latin Abstract
NMR spectroscopy and gas chromatography were used on methanolic solutions of fatty acid methyl esters and on small bilayer liposomes to study the radical-induced denaturation of the fatty acid residues from the natural cis-configuration into trans-isomers. To analyze the mechanism of the thiyl radical-catalyzed lipid isomerization, we compared the effects of thiols on oleic and linoleic fatty acid residues using pulse radiolysis, γ-radiolysis and chemolysis (AAPH) to generate thiyl radicals. The isomerization step takes place within the adduct of the thiyl radical to an olefinic group of unsaturated fatty acids, but not within the pentadienyl radical. The stability of the adduct can be described by an equilibrium constant of (12±5) mol−1 dm3. The isomerization rate depends on the structure of the thiol. However, the resulting isomeric equilibrium (trans-fraction: 81%) does not depend on the structure of the thiyl radical or the organization of the lipids. Quantum chemical calculations were performed to estimate the barriers for rotation, the geometry and the enthalpy difference between cis- and trans-thiyl radical adducts.
From Page
91
NaturalLanguageKeyword
pulse radiolysis , Q-Irradiation , Liposome , Fatty acid , thiol , Isomerization
JournalTitle
Studia Iranica
To Page
100
To Page
100
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