Baker M S, Gebicki J M
Arch Biochem Biophys. 1986 May 1;246(2):581-8. doi: 10.1016/0003-9861(86)90313-9.
The efficiency of conversion of superoxide to hydroxyl radicals was measured by determining the yields of fluorescent hydroxybenzoates. A variety of iron-containing catalysts were tested. Citrate was the only organic salt which showed catalytic activity at neutral pH. Adenine nucleotides had little or no activity under similar conditions. Heme proteins were inactive and any catalytic activity measured with transferrin, lactoferrin, and conalbumin could be explained by free Fe3+ released by the former two at acid pH. Many of the potential catalysts tested showed maximum activity near pH 4.8, where the rate of dismutation of O2-. is highest. This suggests that in most systems the rate-controlling step in the superoxide-driven Fenton process was the formation of H2O2. It was concluded that, with the exception of citrate, none of the biological compounds tested were able to assist the conversion of O2-. to HO. with significant efficiency at neutral pH in homogeneous solutions.
通过测定荧光羟基苯甲酸酯的产率来衡量超氧化物向羟基自由基的转化效率。测试了多种含铁催化剂。柠檬酸盐是唯一在中性pH下显示催化活性的有机盐。腺嘌呤核苷酸在类似条件下几乎没有活性。血红素蛋白无活性，用转铁蛋白、乳铁蛋白和伴清蛋白测得的任何催化活性都可以用前两者在酸性pH下释放的游离Fe3+来解释。测试的许多潜在催化剂在pH 4.8附近显示出最大活性，此时O2-的歧化速率最高。这表明在大多数系统中，超氧化物驱动的芬顿过程中的速率控制步骤是H2O2的形成。得出的结论是，除柠檬酸盐外，在均相溶液中，测试的生物化合物在中性pH下均不能有效地促进O2-向HO·的转化。
