Catalytic metals, ascorbate and free radicals: Combinations to avoid
Catalytic metals, ascorbate and free radicals: Combinations to avoid
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DOI：
10.2307/3579271
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发表时间：
1996-05-01
影响因子：
3.4
通讯作者：
Jurkiewicz, BA
中科院分区：
文献类型：
--
作者：
Buettner, GR;Jurkiewicz, BA
微量过渡金属可以参与金属催化的Haber-Weiss反应（超氧化物驱动的Fenton反应），也可以催化抗坏血酸的氧化。抗坏血酸通常被认为是一种很好的还原剂；它能够在自由基介导的氧化过程中作为供体抗氧化剂。然而，作为还原剂，它也能够还原具有氧化活性的金属，如铜和铁，从而增加这些金属的促氧化化学性质。因此，抗坏血酸可以作为促氧化剂和抗氧化剂。一般来说，在低抗坏血酸浓度下，抗坏血酸倾向于成为促氧化剂，而在高浓度下，它倾向于成为抗氧化剂。因此存在交叉效应。我们提出，这种交叉效应的“位置”是催化金属浓度的函数。在本报告中，我们讨论：(1)催化金属在自由基介导的氧化中的作用；(2)抗坏血酸作为促氧化剂和抗氧化剂；(3)金属催化抗坏血酸氧化；(4)利用抗坏血酸测定外源性催化金属浓度；(5)使用抗坏血酸自由基作为氧化应激的标志；(6)抗坏血酸和铁作为自由基促氧化剂在癌症光动力治疗中的应用。(C) 1996年，辐射研究学会
Trace levels of transition metals can participate in the metal-catalyzed Haber-Weiss reaction (superoxide-driven Fenton reaction) as well as catalyze the oxidization of ascorbate. Generally ascorbate is thought of as an excellent reducing agent; it is able to serve as a donor antioxidant in free radical-mediated oxidative processes. However, as a reducing agent it is also able to reduce redox-active metals such as copper and iron, thereby increasing the pro-oxidant chemistry of these metals. Thus ascorbate can serve as both a pro-oxidant and an antioxidant. In general, at low ascorbate concentrations, ascorbate is prone to be a pro-oxidant, and at high concentrations, it will tend to be an antioxidant. Hence there is a crossover effect. We propose that the ''position'' of this crossover effect is a function of the catalytic metal concentration. In this presentation, we discuss: (1) the role of catalytic metals in free radical-mediated oxidations; (2) ascorbate as both a pro-oxidant and an antioxidant; (3) catalytic metal catalysis of ascorbate oxidation; (4) use of ascorbate to determine adventitious catalytic metal concentrations; (5) use of ascorbate radical as a marker of oxidative stress; and (6) use of ascorbate and iron as free radical pro-oxidants in photodynamic therapy of cancer. (C) 1996 by Radiation Research Society