ANTIOXIDANT EFFECTS OF UBIQUINONES IN MICROSOMES AND MITOCHONDRIA ARE MEDIATED BY TOCOPHEROL RECYCLING
ANTIOXIDANT EFFECTS OF UBIQUINONES IN MICROSOMES AND MITOCHONDRIA ARE MEDIATED BY TOCOPHEROL RECYCLING
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DOI：
10.1016/0006-291x(90)91971-t
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发表时间：
1990-06-29
影响因子：
3.1
通讯作者：
PACKER, L
中科院分区：
文献类型：
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作者：
KAGAN, V;SERBINOVA, E;PACKER, L
泛醌和生育酚(维生素E)是一种内在的脂类成分，由于它们的抗氧化活性，它们在许多膜中具有稳定作用。生育酚的抗氧化作用源于对自由基的直接清除。虽然泛醌也具有抗氧化作用，但其抗氧化活性的特殊分子机制可能是由于：(I)与脂质自由基直接反应或(Ii)与铬氧自由基相互作用，导致维生素E再生。目前的脂质过氧化结果表明，生育酚是比天然泛酚(泛醌)更强的膜抗氧化剂。因此，在存在类似或更高浓度的生育酚的情况下，泛喹酚(泛醌)的直接清除自由基的作用可能可以忽略不计。为了支持这一点，我们的ESR结果表明，泛醌通过线粒体和微粒体中的电子传递，协同促进依赖NADH和NADPH的酶促生育酚的循环。如果泛喹酚是直接的自由基清除剂，那么它们的消费是可以预期的。进一步提供我们的结论，高效液相色谱测量表明，泛醌依赖的生育酚的节余并不伴随着泛醌的消耗。
Ubiquinones and tocopherols (vitamin E) are intrinsic lipid components which have a stabilizing function in many membranes attributed to their antioxidant activity. The antioxidant effects of tocopherols are due to direct radical scavenging. Although ubiquinones also exert antioxidant properties the specific molecular mechanisms of their antioxidant activity may be due to: (i) direct reaction with lipid radicales or (ii) interaction with chromanoxyl radicals resulting in regeneration of vitamin E. Lipid peroxidation results have now shown that tocopherols are much stronger membrane antioxidants than naturally occurring ubiqinols (ubiquinones). Thus direct radical scavenging effects of ubiquinols (ubiquinones) might be negligible in the presence of comparable or higher concentrations of tocopherols. In support of this our ESR findings show that ubiquinones synergistically enhance enzymic NADH- and NADPH-dependent recycling of tocopherols by electron transport in mitochondria and microsomes. If ubiquinols were direct radical scavengers their consumption would be expected. Further providing our conclusion HPLC measurements demonstrated that ubiquinone-dependent sparing of tocopherols was not accompanied by ubiquinone consumption.