Cytochrome c Peroxidase-Like Activity of Chemically Modified Myoglobins

化学修饰肌红蛋白的细胞色素 c 过氧化物酶样活性

• 批准号: 10640546
• 负责人: TSUKAHARA Keiichi
• 金额: $ 2.05万
• 依托单位: Nara Women's University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640546/
• 关键词: Modified Myoglobin; Cytochrome c; Cytochrome c Peroxidase; Hydrogen Peroxide; Enzymatic Activity; Ferryl Myoglobin; Aminopolycarboxylate; Diethylenetriaminepentaacetic Acid; Modified Myoglobin; Cytochrome c; Cytochrome c Peroxidase; Hydrogen Peroxide; Enzymatic Activity; Ferryl Myoglobin; Aminopolycarboxylate; Diethylenetriaminepentaacetic Acid

Horse heart metmyoglobin (metMb), whose lysine residues were modified with diethylenetriaminepentaacetic acid (DTPA), was characterized by a MALDI-TOF mass spectroscopy, an amino-acid sequence analysis, and UV-Vis and CD spectroscopies. Kinetics of the oxidation of the reduced cytochrome c (cyt c(II)) wit hydrogen peroxide catalyzed by metMb(DTPA)ィイD2nィエD2(n = 1, 2, 4, and 5) was investigated spectrophotometrically compared with native metMb. The modified metMb(DTPA)ィイD2nィエD2 showed the cytochrome c peroxidase-like activity more efficiently than the native metMb (metMb(DTPA)ィイD25ィエD2 > metMb(DTPA)ィイD24ィエD2 > metMb(DTPA)ィイD22ィエD2 > metMbDTPA 【greater than or equal】 native metMb). The native metMb does not bind cyt c(II), but metMb(DTPA)ィイD2nィエD2 can bind cyt c(II) with an anionic patch where DTPA anions are liked to the Lys residue(s) on the surface of metMb. The formation of the diprotein complex of metMb(DTPA)ィイD2nィエD2 with cyt c(II) accelerates the electron-transfer (ET) reaction fro … More m cyt c(II) to ferrylMb. An intermediate ferrylMb-protein radical was also detected by an ESR measurement ; it might be a Tyr146 radical. The photoinduced ET reaction between cyt c(III) and zinc-substituted myoglobin modified with DTPA ions, was reexamined. The first-order rate constant for the concentrations of cyt c(III), suggesting ZnMb(DTPA)ィイD2nィエD2(n = 2, 4, and 5) was saturated with increasing the concentrations of cyt c(III), suggesting that the ET quenching occurs within a diprotein complex. The formation constant for the diprotein complex increased with increasing the number of DTPA ions on the lysine residues of myoglobin and decreased with increasing ionic strength, indicating that cyt c(III) interacts with the DTPA anionic patch. The intermolecular ET rate constants in the diprotein complex increased with increasing the number of DTPA ions and decreased with increasing ionic strength. It is suggested that a gating occurs by fluctuation in the configuration of a diprotein complex. Less

赖氨酸残留物用二乙基苯甲酸乙酸乙酸（DTPA）修饰，其马心Metmyoglobin（METMB）的特征是通过MALDI-TOF质谱，氨基酸序列分析和UV-VIS和CD光谱法进行了特征。与与天然METMB相比，研究了通过METMB（DTPA）II D2 NIE D2催化的细胞色素C（C（II））WIT氢过氧化氢的动力学。改进的METMB（DTPA）D2NIE D2比天然METMB（METMB（DTPA）D25I D2> METMB（DTPA）D24I D2> METMB（DTPA）D22I D2> METMBDTPA [更大于或更大于METMBDTPA [更大于或更大于METMB）[METMB（DTPA）D25I D2> METMB（DTPA）D2> METMB（DTPA）D2> METMB（DTPA）D2> METMB（DTPA）D2> METMB（DTPA）d2nie D2比本机METMB（METMB（DTPA）D25I D2> METMB（DTPA）D2> METMB（DTPA）d2> METMBDTPA [更大：天然METMB不结合Cyt C（II），但是METMB（DTPA）D2NIE D2可以将Cyt C（II）与阴离子贴片结合，其中DTPA阴离子喜欢METMB表面的LYS居住（S）。 METMB（DTPA）D2NIE D2与Cyt C（II）的二蛋白络合物的形成加速了电子转移（ET）反应，而更多的M Cyt C（II）到FerryLMB。通过ESR测量，还检测到中间的ferrylmb蛋白质自由基。它可能是Tyr146激进分子。重新检查了Cyt C（III）和锌取代的肌红蛋白之间的光诱导的ET反应，是通过DTPA离子修饰的。 Cyt C（III）浓度的一阶速率常数，表明ZnMB（DTPA）D2NIE D2（n = 2、4和5）饱和，表明Cyt C（iii）的浓度增加，表明ET淬灭在二蛋白蛋白复合物中发生。二蛋白复合物的形成常数随着肌红蛋白赖氨酸保留的DTPA离子数量的增加而增加，并随离子强度的增加而增加，表明Cyt C（III）与DTPA阴离子斑块相互作用。二蛋白复合物中的分子间ET速率常数随着DTPA离子数量的增加而增加，并且随离子强度的增加而增加。建议通过在偶曲蛋白复合物的构型中波动发生门控。较少的