Fukuzawa K, Takase S, Tsukatani H
Arch Biochem Biophys. 1985 Jul;240(1):117-20. doi: 10.1016/0003-9861(85)90013-x.
Egg yolk phosphatidylcholine liposomes were rapidly oxidized in the presence of chelated iron and a superoxide-generating system. alpha-Tocopherol incorporated in the bilayer was oxidized at the same time. No lipid or alpha-tocopherol oxidation occurred in liposomes composed of dimyristoyl phosphatidylcholine. The antioxidant did not inhibit lipid peroxidation until its concentration reached a critical level, which depended on the effectiveness of the oxidative stress. Beyond this level, peroxidation was inhibited completely and, simultaneously, the rate of oxidation of tocopherol was lowered. The results suggest that the antioxidant efficiency of alpha-tocopherol depends on its ability to react mainly with the chain-initiating or chain-propagating lipid radicals. This, in turn, is closely tied to the tocopherol content of the membrane. Ascorbate inhibited the consumption of alpha-tocopherol, possibly by regenerating its reduced form.
在螯合铁和超氧化物生成系统存在的情况下，蛋黄磷脂酰胆碱脂质体迅速被氧化。掺入双层膜中的α-生育酚同时被氧化。由二肉豆蔻酰磷脂酰胆碱组成的脂质体中未发生脂质或α-生育酚氧化。抗氧化剂直到其浓度达到临界水平才抑制脂质过氧化，该临界水平取决于氧化应激的有效性。超过这个水平，过氧化被完全抑制，同时，生育酚的氧化速率降低。结果表明，α-生育酚的抗氧化效率取决于其主要与引发链或传播链的脂质自由基反应的能力。反过来，这又与膜中的生育酚含量密切相关。抗坏血酸盐可能通过再生其还原形式来抑制α-生育酚的消耗。
