Fukuzawa K, Tokumura A, Kogure K, Iemura M, Gondoh N, Fujii M, Ueno S, Shibata A
Department of Health Chemistry, School of Medical Sciences, Tokushima University, 1-78 Shomachi, Tokushima 770-8505, Japan.
Chem Phys Lipids. 2001 Mar;110(1):69-84. doi: 10.1016/s0009-3084(01)00127-x.
This study examined some of the variables determining the efficiency of lipid peroxidation in egg yolk phosphatidylcholine liposomes and in microsomes exposed to enzymatically-generated superoxide radicals. The initiation of peroxidation required the presence of preformed lipid peroxides and a chelated metal catalyst. Comparison of the relative effectiveness of four iron chelating agents showed that the chelate must bind to the membrane by coulombic attraction between the charged membrane and a chelate carrying an opposite net charge. Of the chelates tested, only the carcinogenic ferric nitrilotriacetate [corrected] (Fe(3+)-NTA) was an effective catalyst of oxidation of all membranes, whether carrying a net charge, or not. We postulate that the unique catalytic capacity of the ferric nitrilotriacetate [corrected] (Fe(3+)-NTA) can be explained by its existence in two forms at neutral pH, each binding to oppositely charged membranes and initiating their peroxidation. This gives the complex the unique ability to bind to any membrane, which may be a factor in its carcinogenicity.
本研究考察了一些决定蛋黄磷脂酰胆碱脂质体和暴露于酶促产生的超氧自由基的微粒体中脂质过氧化效率的变量。过氧化反应的引发需要预先形成的脂质过氧化物和一种螯合金属催化剂的存在。对四种铁螯合剂相对有效性的比较表明，螯合物必须通过带电荷的膜与带有相反净电荷的螯合物之间的库仑吸引力与膜结合。在所测试的螯合物中，只有致癌性的次氮基三乙酸铁（Fe(3+)-NTA）是所有膜氧化的有效催化剂，无论膜是否带有净电荷。我们推测，次氮基三乙酸铁（Fe(3+)-NTA）独特的催化能力可以通过其在中性pH下以两种形式存在来解释，每种形式都与带相反电荷的膜结合并引发其过氧化反应。这赋予了该复合物与任何膜结合的独特能力，这可能是其致癌性的一个因素。
