The lactate-dependent enhancement of hydroxyl radical generation by the Fenton reaction
The lactate-dependent enhancement of hydroxyl radical generation by the Fenton reaction
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DOI：
10.1080/10715760000300431
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发表时间：
2000-01-01
影响因子：
3.3
通讯作者：
Konishi, T
中科院分区：
文献类型：
--
作者：
Ali, MA;Yasui, F;Konishi, T
研究了乳酸（乳酸盐）对芬顿体系羟基自由基（（OH）-O-.）以DMPO和香豆素-3-羧酸（3-CCA）为（OH）-O-，通过自旋捕集、ESR和荧光方法研究了产物。各自的陷阱。（OH）-O-。在两个实验中，加合物的形成被高达0.4mM的乳酸盐（乳酸盐/铁化学计量比= 2）抑制，但是随着乳酸盐浓度的增加而显著增强，乳酸盐浓度高于该临界浓度。当检查H2 O2依赖性时，DMPO-OH信号随着H2 O2浓度线性增加，直至1 mM，然后在不存在乳酸盐的情况下饱和。然而，在乳酸盐的存在下，DMPO-OH信号随着高于ImM的H2 O2浓度而进一步增加，并且饱和水平也依赖于乳酸盐浓度而增加。光谱研究表明，当乳酸盐/Fe ~（3+）= 2时，乳酸盐与Fe ~（3+）形成稳定的有色络合物，络合物的形成与DMPO-OH的形成密切相关。络合物的形成没有促进H2 O2介导的Fe 3+还原。当Fe ~（3+）-乳酸盐（1：2）配合物与H_2O_2反应时，羟基化3-CCA的初始生成速率随H_2O_2浓度线性增加。实验结果表明，在芬顿反应体系中形成的Fe ~（3+）-乳酸盐（1：2）络合物直接与H_2O_2反应生成额外的（OH）-O-。在芬顿反应中，通过乳酸盐或乳酸盐/Fe 3+介导的促进Fe 3 +/Fe 2+氧化还原循环以外的其他机制。
The effect of lactic acid (lactate) on Fenton based hydroxyl radical ((OH)-O-.) production was studied by spin trapping, ESR, and fluorescence methods using DMPO and coumarin-3-carboxylic acid (3-CCA) as the (OH)-O-. traps respectively. The (OH)-O-. adduct formation was inhibited by lactate up to 0.4 mM (lactate/iron stoichiometry = 2) in both experiments, but markedly enhanced with increasing concentrations of lactate above this critical concentration. When the H2O2 dependence was examined, the DMPO-OH signal was increased linearly with H2O2 concentration up to 1 mM and then saturated in the absence of lactate. In the presence of lactate, however, the DMPO-OH signal was increased further with higher H2O2 concentration than 1 mM, and the saturation level was also increased dependent on lactate concentration. Spectroscopic studies revealed that lactate forms a stable colored complex with Fe3+ at lactate/Fe3+ stoichiometry of 2, and the complex formation was strictly related to the DMPO-OH formation. The complex formation did not promote the H2O2 mediated Fe3+ reduction. When the Fe3+-lactate (1:2) complex was reacted with H2O2, the initial rate of hydroxylated 3-CCA formation was linearly increased with H2O2 concentrations. All the data obtained in the present experiments suggested that the Fe3+-lactate (1:2) complex formed in the Fenton reaction system reacts directly with H2O2 to produce additional (OH)-O-. in the Fenton reaction by other mechanisms than lactate or lactate/Fe3+ mediated promotion of Fe3+/Fe2+ redox cycling.