The FeII(citrate) Fenton reaction under physiological conditions
The FeII(citrate) Fenton reaction under physiological conditions
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DOI：
10.1016/j.jinorgbio.2020.111018
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发表时间：
2020-05-01
影响因子：
3.9
通讯作者：
Meyerstein, Dan
中科院分区：
文献类型：
--
作者：
Illes, Erzsebet;Patra, Shanti G.;Meyerstein, Dan
研究了在存在和不存在碳酸氢盐 (HCO3-) 的情况下 Fe-II（柠檬酸盐）的芬顿反应。研究发现芬顿反应的速率常数 (k(obs)) 随着[柠檬酸盐]的增加而增加。 (kobs) 也随着 [HCO3-] 的增加而增加；这种效应在生物柠檬酸盐浓度下最为显着。当芬顿反应在大量[柠檬酸根]存在下进行时，由于柠檬酸根（-2OC）CH2C（OH）（CO2）CH（CO2）中心点/（-2OC）CH2C（O）（CO2-）CH2（CO2-）中心点与（CH3）（2）SO反应，由（CH3）（2）SO形成甲烷和乙烷气体。在没有柠檬酸盐的情况下，(CH3)(2)SO2 是芬顿反应的主要产物。然而，在 0.10 mM 柠檬酸盐存在下，不会形成 (CH3)(2)SO2，而是会形成一些 (CH3)SOOH，同时 β-戊二酸的产率较低。 (CH3)SOOH 和 β-酮戊二酸的形成是由于柠檬酸根和 Fe-IV（柠檬酸盐）造成的。在碳酸氢盐存在下，丰富的 β-酮戊二酸的形成证实了碳酸根阴离子（CO3 中心点（-））的形成。因此，碳酸氢盐极大地影响反应的机理和动力学。羟基自由基（OH 中心点）在碳酸氢盐存在的情况下不会形成，在碳酸氢盐不存在的情况下也可能不会形成。这些结果表明，芬顿反应形成的羟基自由基不会引发生物系统中的氧化应激。
The Fenton reaction of Fe-II(citrate) in the presence and absence of bicarbonate (HCO3-) is studied. It is found that the rate constant of the Fenton reaction (k(obs)) increases with increasing [citrate]. (kobs) also increase with increasing [HCO3-]; this effect is most significant at biological citrate concentrations. Methane and ethane gases are formed from (CH3)(2)SO when the Fenton reaction is carried out in the presence of large [citrate] due to the reaction of the citrate radical, (-2OC)CH2C(OH)(CO2)CH(CO2)center dot/(-2OC)CH2C(O)(CO2-)CH2(CO2-) center dot with (CH3)(2)SO. In the absence of citrate (CH3)(2)SO2 is the main product of the Fenton reaction. However, in the presence of 0.10 mM citrate, no (CH3)(2)SO2 is formed, some (CH3)SOOH is formed, along with a low yield of betaketoglutaric acid. Formation of (CH3)SOOH and beta-ketoglutaric acid are due to the citrate radical and Fe-IV (citrate). In the presence of bicarbonate formation of abundant beta-ketoglutaric acid confirms the formation of carbonate radical anion (CO3 center dot(-)). Thus, bicarbonate affects the mechanism and kinetics of the reaction dra- matically. Hydroxyl radicals (OH center dot) are not formed in the presence of bicarbonate and probably also not in its absence. These results point out that hydroxyl radicals, formed by the Fenton reaction, do not initiate oxidative stress in biological systems.