Scheschonka A, Murphy M E, Sies H
Institut für Physiologische Chemie I, Universität Düsseldorf, F.R.G.
Chem Biol Interact. 1990;74(3):233-52. doi: 10.1016/0009-2797(90)90041-k.
Microsomal membranes exposed to various prooxidants displayed distinct patterns in the temporal relationships between the loss of antioxidants and the onset of lipid peroxidation. Prooxidants included ADP-chelated iron with reductants (NADPH and ascorbate), or compounds that generate peroxyl radicals (tert-butyl hydroperoxide and 2,2'-azobis(2-amidinopropane)), or free metal ions (Fe2+ and Cu2+). Lipid peroxidation initiated by Fe2+ began simultaneously with the loss of alpha-tocopherol, while about 15% of alpha-tocopherol was lost during the lag phase preceding lipid peroxidation in systems containing chelated iron. A substantial depletion of alpha-tocopherol (49-69%) preceded peroxidation when initiated by peroxyl radicals, while 97% of the antioxidant disappeared preceding peroxidation initiated by copper. The loss of protein sulfhydryl groups also varied between the prooxidants (ranging from 0 to 82% loss prior to the onset of peroxidation) to a degree that roughly paralleled the loss of vitamin E. Therefore, important determinants of peroxidation are prooxidant-dependent, and not only include alpha-tocopherol and sulfhydryl groups, but also membrane integrity, propagation reactions and the availability of catalytic transition metals.
暴露于各种促氧化剂的微粒体膜在抗氧化剂丧失与脂质过氧化开始之间的时间关系上呈现出不同模式。促氧化剂包括与还原剂（NADPH和抗坏血酸）结合的ADP螯合铁、产生过氧自由基的化合物（叔丁基过氧化氢和2,2'-偶氮二(2-脒基丙烷)）或游离金属离子（Fe2+和Cu2+）。由Fe2+引发的脂质过氧化与α-生育酚的丧失同时开始，而在含有螯合铁的体系中，脂质过氧化之前的滞后阶段有大约15%的α-生育酚丧失。当由过氧自由基引发时，α-生育酚会大量消耗（49 - 69%），而过氧化由铜引发之前，97%的抗氧化剂消失。蛋白质巯基的丧失在不同促氧化剂之间也有所不同（过氧化开始前丧失范围为0至82%），其程度大致与维生素E的丧失平行。因此，过氧化的重要决定因素取决于促氧化剂，不仅包括α-生育酚和巯基，还包括膜完整性、传播反应以及催化过渡金属的可用性。
