含N轴向配位体对金属卟啉催化活性的影响

Effect of axial ligands on the catalytic activities of metalloporphyrin

目的 :从模拟生物分子的观点出发 ,探讨轴向配位体对金属卟啉 过氧化物模拟酶催化活性的影响。方法 :研究了几种配位体对meso 四 (4 磺基苯 )卟啉 (TPPS4)的Fe衍生物的轴向配位作用 ,用紫外 可见光谱滴定法测定了它们的轴向配位稳定常数 ,并利用动力学方法 ,检测了轴向配位对金属卟啉催化性能的影响。结果 :与天然酶配体结构类似的咪唑和吡啶等配位体对金属卟啉的配位稳定常数是咪唑 >吡啶 >γ 甲基吡啶 ,而轴向配位后对金属卟啉的催化活性有明显的增强作用。结论 :咪唑、吡啶、γ 甲基吡啶轴向配位可以改善模拟酶的催化特性 ,其影响程度取决于配位体同金属卟啉的配位能力。

Objective:Started off from the viewpoint mimic bioactive molecules,to explore the effect of axial lig ands on the catalytic activ ities of metalloporphyrins as mimetic peroxidase. Methods:The effects of several axial ligands on meso-tetra(4- sulphophenyl)porphin Fe were investigated, and the stability constants of the ax ial coordination reaction were detected by means of spectrophotometer technique. Using the method of muzzle velocity, the catalytic activities of the metallopor phyrin with axial ligands were compared. Results:The metalloporphyrin with ligands similar to natural en zymes had different stability constants. Imidazole showed the highest constants , followed by pyridine, then was γ-methylpyridine. It was also indicated that axial ligands of metalloporphyrin could enhance activity of catalase. Conclusion:The axial coordination of imidazole, pyridine and γ -methylpyridine appears to enhance the catalase activity of mimetic enzymes, wh ich is depended on ligands' coordinating ability with the metalloporphyrin.