Superoxide Dismutase Activity of Iron(II)TPEN Complex and Its Derivatives.
作者:Masakazu TAMURA、Yasuteru URANO、Kazuya KIKUCHI、Tsunehiko HIGUCHI、Masaaki HIROBE、Tetsuo NAGANO
DOI:10.1248/cpb.48.1514
日期:——
Superoxide is involved in the pathogenesis of various diseases, such as inflammation, ischemia-reperfusion injury and carcinogenesis. Superoxide dismutases (SODs) catalyze the disproportionation reaction of superoxide to produce oxygen and hydrogen peroxide, and can protect living cells against the toxicity of free radicals derived from oxygen. Thus, SODs and their functional mimics have potential value as pharmaceuticals. We have previously reorted that Fe(II)tetrakis-N, N, N', N'-(2-pyridylmethyl)ethylenediamine (Fe(II)TPEN) has an excellent SOD activity (IC50=0.5μM) among many iron complexes examined (J. Biol. Chem., 264, 9243-9249(1989)).Fe(II)TPEN can act like native SOD in living cells, and protect Escherichia coli cells from free radical toxicity caused by paraquat.In order to develop more effective SOD functional mimics, we synthesized Fe(II)TPEN derivatives with electron-donating or electron-withdrawing groups at the 4-position of all pyridines of TPEN, and measured the SOD activities and the redox potentials of these complexes. Fe(II) tetrakis-N, N, N', N'-(4-methoxy-2-pyridylmethyl)ethylenediamine (Fe(II)(4MeO)4TPEN) had the highest SOD activity (IC50=0.1 μM) among these iron-based SOD mimics. In addition, a good correlation was found between the redox potential and the SOD activity of 15 Fe(II)complexes, including iron-based SOD mimics reported in the previous paper (J. Organometal. Chem., in press).Iron-based SOD mimics may be clinically applicable, because these complexes are generally tissue-permeable and show low toxicity. Therefor our findings should be significant for the development of clinically useful SOD mimics.
超氧化物与炎症、缺血再灌注损伤和致癌等多种疾病的发病机制有关。超氧化物歧化酶(SOD)能催化超氧化物的歧化反应,生成氧气和过氧化氢,并能保护活细胞免受来自氧气的自由基的毒性。因此,SODs 及其功能模拟物具有潜在的药物价值。我们以前曾报告过,在众多铁络合物中,Fe(II)四-N, N, N', N'-(2-吡啶基甲基)乙二胺(Fe(II)TPEN)具有出色的 SOD 活性(IC50=0.5μM)(J. Biol.为了开发更有效的 SOD 功能模拟物,我们合成了在 TPEN 所有吡啶的 4 位上带有电子供体或电子吸附基团的 Fe(II)TPEN 衍生物,并测量了这些复合物的 SOD 活性和氧化还原电位。在这些铁基 SOD 模拟物中,Fe(II) tetrakis-N, N, N', N'-(4-methoxy-2-pyridylmethyl)ethylenediamine(Fe(II)(4MeO)4TPEN)的 SOD 活性最高(IC50=0.1 μM)。此外,我们还发现 15 种铁(II)复合物的氧化还原电位与 SOD 活性之间存在良好的相关性,其中包括上一篇论文(《有机金属化学》,出版中)中报道的铁基 SOD 模拟物。因此,我们的研究结果对于开发临床上有用的 SOD 模拟物应该具有重要意义。