Axial ligand coordination in intestinal peroxidase.
Axial ligand coordination in intestinal peroxidase.
复制标题
肠过氧化物酶中的轴向配体协调。
DOI：
10.1016/0003-9861(90)90653-g
复制
发表时间：
1990
影响因子：
3.9
通讯作者：
Kimura,S
中科院分区：
文献类型：
--
作者：
Ikeda-Saito,M;Kimura,S
首次报道了肠过氧化物酶的EPR谱。肠道过氧化物酶的静止状态下，只有一个高自旋EPR谱与pH依赖的菱形。氯化物的加入改变了酶的酸性和中性形式之间的平衡。与此相反，休息乳过氧化物酶显示EPR谱的低自旋和高自旋的物种，表明这两个过氧化物酶之间的不同血红素环境。乳过氧化物酶的高自旋信号由多个组分组成;主要组分表现出类似于肠过氧化物酶的pH依赖性菱形，并且酸性和中性形式之间的平衡也被氯离子移动。EPR功能的低自旋氰化物复合物的肠过氧化物酶和乳过氧化物酶进行了比较与其他血红素蛋白，其近端轴向配体是已知的组氨酸残基。哺乳动物过氧化物酶的氰化物加合物的g值是相似的。讨论了近端组氨酸的g值各向异性与咪唑特征之间的关系。
EPR spectra of intestinal peroxidase are reported for the first time. The resting state of intestinal peroxidase exhibits only a high spin EPR spectrum with pH-dependent rhombicity. Addition of chloride shifts the equilibrium between an acidic and a neutral form of the enzyme. In contrast, resting lactoperoxidase shows EPR spectra of both low spin and high spin species, indicating a different heme environment between these two peroxidases. The high spin signal of lactoperoxidase consists of multiple components; the major component exhibits pH-dependent rhombicity similar to intestinal peroxidase and the equilibrium between the acidic and the neutral forms is also shifted by chloride ion. EPR features of the low spin cyanide complex of intestinal peroxidase and lactoperoxidase are compared with those of other hemeproteins, whose proximal axial ligands are known to be histidine residues. Theg-values of the cyanide adducts of the mammalian peroxidases are similar. The relationship between theg-value anisotropy and imidazolate character of the proximal histidine is discussed.