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Spectroscopic and Magnetochemical Studies on the Structures and Functions of Active Centers in Intact Cells

完整细胞活性中心结构和功能的光谱和磁化学研究

基本信息

批准号：
04453046
负责人：
HIROTA Noboru
金额：
$ 4.61万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04453046/
关键词：
Iron Complex Manganese Complex Fe-SOD ESR Active Oxygen Spin-trap 金属酵素モデル錯体

项目摘要

The ESR spectrometer system was improver by computerizing the system. The following studies were made using the improved system.1) Studies of Model Systems As models of catecho1-dioxygenases iron complexes with various ligands were studeied. Active species in thereaction processes were identified and the reaction scheme involving many intermediates was proposed. As models of manganese-catalases manganese complexes with oxygen/nitrogen mixed ligands were studied, and their solution structures and the reactivities towards hydrogen peroxide were studied. Necessary conditions for activating managanese catalases were suggested on the basis of the obtained results.2) Studies of Biological Systems Metal containing enzymes in Escherichia Coliwere studied in intact cells. The signals due to Fe-SOD and other iron clusters were identified. The differences in the ESR parameters between the purified enzymes and intact cells were examined. The function of luteoskyrin was studied by means of spin-trapping method. The conditions under which luteoskyrin is converted to semiquinone radical in microsome and the possibility of producing oxygen and OH radicals were studied. It was suggested that the effect of luteoskyrin toliver is due to the active oxygen species produced by the oxidation of the semiquinone radical formed in the one-electron reduction system.

对ESR谱仪系统进行了计算机化改造。1）模型体系的研究作为儿茶酚双加氧酶的模型体系，研究了不同配体的铁配合物。确定了反应过程中的活性物种，提出了涉及多个中间体的反应方案。以氧氮混合配体锰配合物为模型化合物，研究了它们的溶液结构和对过氧化氢的反应性。在此基础上提出了激活锰过氧化氢酶的必要条件。2）生物系统的研究在完整细胞中研究了大肠杆菌含金属酶。鉴定了由于Fe-SOD和其他铁簇的信号。研究了纯化酶和完整细胞之间ESR参数的差异。用自旋捕获法研究了木犀草素的功能。研究了叶黄素在微粒体中转化为半醌自由基的条件以及产生氧自由基和OH自由基的可能性。初步认为，木犀草素的抗氧化作用是由于单电子还原体系中半醌自由基氧化产生的活性氧所致。