ASCORBATE IS AN OUTSTANDING ANTIOXIDANT IN HUMAN-BLOOD PLASMA
ASCORBATE IS AN OUTSTANDING ANTIOXIDANT IN HUMAN-BLOOD PLASMA
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DOI：
10.1073/pnas.86.16.6377
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发表时间：
1989-08-01
影响因子：
11.1
通讯作者：
AMES, BN
中科院分区：
文献类型：
--
作者：
FREI, B;ENGLAND, L;AMES, BN
我们最近已经表明，暴露于恒定流量的水性过氧自由基的人血浆中抗氧化剂消耗的时间顺序是抗坏血酸盐=蛋白质硫醇>胆红素>尿酸盐> α-过氧化氢。生育酚和可检测的脂质过氧化作用仅在抗坏血酸盐完全消耗后开始。在本文中，我们表明，它确实是抗坏血酸，完全保护血浆脂质对可检测的过氧化损伤引起的水过氧自由基和抗坏血酸是唯一的血浆抗氧化剂，可以这样做。血浆缺乏抗坏血酸，但没有其他内源性抗氧化剂，是非常容易受到氧化应激和脂质过氧化损伤。血浆蛋白的硫醇，虽然它们在暴露于水性过氧自由基后立即被氧化，但它们是无效的自由基清除剂，并且似乎主要通过自氧化被消耗。我们的数据表明，抗坏血酸是最有效的水相抗氧化剂在人体血浆中，并表明，在人类抗坏血酸是一种生理抗氧化剂的重要性，对疾病和氧化应激引起的退行性过程的保护。
We have shown recently that the temporal order of antioxidant consumption in human blood plasma exposed to a constant flux of aqueous peroxyl radicals is ascorbate = protein thiols > bilirubin > urate > .alpha.-tocopherol and that detectable lipid peroxidation starts only after ascorbate has been consumed completely. In this paper, we show that it is indeed ascorbate that completely protects plasma lipids against detectable peroxidative damage induced by aqueous peroxyl radicals and that ascorbate is the only plasma antioxidant that can do so. Plasma devoid of ascorbate, but no other endogenous antioxidant, is extremely vulnerable to oxidant stress and susceptible to peroxidative damage to lipids. The plasma proteins'' thiols, although they become oxidized immediately upon exposure to aqueous peroxyl radicals, are inefficient radical scavengers and appear to be consumed mainly by autoxidation. Our data demonstrate that ascorbate is the most effective aqueous-phase antioxidant in human blood plasma and suggest that in humans ascorbate is a physiological antioxidant of major importance for protection against diseases and degenerative processes caused by oxidant stress.