Hidden Complexity in the Mechanism of the Autoreduction of Myoglobin Compound II.
Hidden Complexity in the Mechanism of the Autoreduction of Myoglobin Compound II.
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DOI：
10.1021/acsomega.2c02798
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发表时间：
2022-07-05
期刊：
影响因子：
4.1
通讯作者：
Williamson, Heather R.
中科院分区：
文献类型：
--
作者：
Hill, Kamisha R.;Bailey, Breanna G.;Mouton, Meghan B.;Williamson, Heather R.
马心脏肌红蛋白与过氧化氢的非天然氧化产生化合物II，其通过利用内部氧化位点自动还原。在这里，我们利用全紫外可见时间相关动力学和全局动力学奇异值分解分析来探索机制并揭示更多关于高价血红素光谱特征的细节。通过改变过氧化氢和肌红蛋白的浓度，我们能够揭示更详细的肌红蛋白化合物II的光谱和在几种不同的pH条件下的自还原速率。化合物II的光谱表现出pH依赖性，拐点在pH 5.7±0.1左右。化合物II （k2）的自还原速率随pH值的降低而增加，且具有半功率的质子依赖关系，且没有pKa bb0（3.9±0.2）的迹象，表明自还原仍然依赖于铁基氧的质子化。k2也表现出双氧水和肌红蛋白的依赖性。在肌红蛋白浓度大于6.6 μM时，k2与肌红蛋白无关，但在较低浓度时，k2与ph敏感。
The non-native oxidation of horse heart myoglobin with hydrogen peroxide produces compound II which autoreduces by utilizing an internal oxidation site. Here, we utilize full UV–visible time-dependent kinetics with global kinetic singular value decomposition analysis to explore the mechanism and uncover more detail about the high-valent heme spectral features. By varying the hydrogen peroxide and myoglobin concentration, we were able to uncover more detailed spectra of myoglobin compound II and the autoreduction rate under several different pH conditions. The compound II spectra demonstrate pH-dependent features with an inflection point around pH 5.7 ± 0.1. The rate of autoreduction of compound II, k2, increases with lower pH with a half-power proton dependence and no indication of a pKa > 3.9 ± 0.2, indicating that the autoreduction is still dependent on the protonation of the ferryl oxo species. The k2 also demonstrates both hydrogen peroxide and myoglobin dependency. At myoglobin concentrations greater than 6.6 μM, the k2 is myoglobin-independent, but for lower concentrations, a pH-sensitive concentration dependence is seen.
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影响因子：
4.6
作者：
Rittle, Jonathan;Younker, Jarod M.;Green, Michael T.
通讯作者：
Green, Michael T.
影响因子：
4.1
作者：
Silaghi-Dumitrescu, Radu;Reeder, Brandon J.;Wilson, Michael T.
通讯作者：
Wilson, Michael T.
影响因子：
4.1
作者：
FOOTE, N;GADSBY, PMA;THOMSON, AJ
通讯作者：
THOMSON, AJ
影响因子：
2.9
作者：
BASHFORD, D;CASE, DA;WRIGHT, PE
通讯作者：
WRIGHT, PE
DOI：
10.1016/0167-4838(91)90529-9
发表时间：
1991-03-08
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
DAVIES, MJ
通讯作者：
DAVIES, MJ