Schwinn J, Sprinz H, Drössler K, Leistner S, Brede O
Research Unit Time-resolved Spectroscopy, Leipzig, Germany.
Int J Radiat Biol. 1998 Sep;74(3):359-65. doi: 10.1080/095530098141492.
To investigate the role of a thiol-containing biologically active compound in lipid peroxidation of membranes.
Thiyl radicals were generated from 3-(2-mercaptoethyl)quinazoline-2,4(1H,3H)-dione (MECH) using pulse radiolysis and gamma-radiolysis in aqueous and alcoholic solutions saturated with N2O. The products were analysed by 1H NMR and by HPLC.
THE thiyl radicals abstract bisallylic hydrogens from [cis-9, cis-12]-methyl linoleate, yielding a pentadienyl radical. In the absence of oxygen, a thiyl radical-induced cis/trans-isomerization leads to linoleic-type isomers. These chain-type isomerization reactions can occur with the long living pentadienyl radical, followed by a 'repair' reaction of the attached thiol, and with the thiyl radical adduct with a double bond of the fatty acid residue.
The results show that the mechanism of cis/trans-isomerization is an integral part of the thiyl radical attack on polyunsaturated fatty acids in homogeneous solutions and in bilayers.
研究一种含硫醇的生物活性化合物在膜脂质过氧化中的作用。
在饱和N₂O的水溶液和醇溶液中，使用脉冲辐解和γ辐解从3-(2-巯基乙基)喹唑啉-2,4(1H,3H)-二酮（MECH）产生硫自由基。产物通过¹H NMR和HPLC进行分析。
硫自由基从[顺-9,顺-12]-亚油酸甲酯中夺取双烯丙基氢，生成戊二烯基自由基。在无氧条件下，硫自由基诱导的顺/反异构化导致亚油酸型异构体的产生。这些链式异构化反应可以与长寿命的戊二烯基自由基发生，随后是连接的硫醇的“修复”反应，也可以与硫自由基加合物与脂肪酸残基的双键发生。
结果表明，顺/反异构化机制是硫自由基在均相溶液和双层膜中攻击多不饱和脂肪酸的一个组成部分。
