通过脉冲辐解研究超氧自由基与乙二胺四乙酸铁配合物的反应。

The reaction of superoxide radical with iron complexes of EDTA studied by pulse radiolysis.

作者信息

Ilan Y A, Czapski G

出版信息

Biochim Biophys Acta. 1977 Jul 21;498(1):386-94. doi: 10.1016/0304-4165(77)90277-x.

Abstract

The reactions of Fe3+-EDTA and Fe2+-EDTA with O2- and CO2- were investigated in the pH range 3.8--11.8. Around neutral pH O2- reduces Fe3+-EDTA with a rate constant which is pH dependent kpH 5.8--8.1 = 2 - 10(6)--5 - 10(5) M-1 - s-1. At higher pH values this reaction becomes much slower. The CO2- radical reduces Fe3+-EDTA with kpH 3.8--1- = 5 +/- 1 - 10(7) M-1 - s-1 independent of pH. At pH 9--11.8, Fe2+-EDTA forms a complex with O2- with kFe2+-EDTA + O2 = 2 - 10(6)--4 - 10(6) M-1 - s-1 which is pH dependent. We measured the spectrum of Fe2+-EDTA-O2- and calculated epsilon 290 over max = 6400 +/- 800 M-1 - cm-1 in air-saturated solutions. In O2-saturated solutions another species is formed with a rate constant of 7 +/- 2 s-1. This intermediate absorbs around 300 nm but we were not able to identify it.

摘要

研究了Fe3+-EDTA和Fe2+-EDTA与O2-和CO2-在pH值3.8至11.8范围内的反应。在中性pH附近，O2-以与pH相关的速率常数还原Fe3+-EDTA，pH 5.8至8.1时，k = 2×10(6)至5×10(5) M-1·s-1。在较高pH值时，该反应变得慢得多。CO2-自由基以k = 5±1×10(7) M-1·s-1还原Fe3+-EDTA，与pH无关。在pH 9至11.8时，Fe2+-EDTA与O2-形成络合物，kFe2+-EDTA + O2 = 2×10(6)至4×10(6) M-1·s-1，这与pH有关。我们测量了Fe2+-EDTA-O2-的光谱，并计算出在空气饱和溶液中ε290 over max = 6400±800 M-1·cm-1。在O2饱和溶液中，以7±2 s-1的速率常数形成另一种物质。该中间体在300 nm左右有吸收，但我们无法鉴定它。