| 细胞色素C与NO的反应机制 |
| Reaction Mechanism of Cytochrome C with NO |
| 作者 | 单位 | E-mail | | 唐乾 | 大连大学生命科学与技术学院, 大连 116622
辽宁省生物有机化学重点实验室, 大连大学, 大连 116622 | | | 史珊珊 | 大连大学生命科学与技术学院, 大连 116622
辽宁省生物有机化学重点实验室, 大连大学, 大连 116622 | | | 曹洪玉 | 大连大学生命科学与技术学院, 大连 116622
辽宁省生物有机化学重点实验室, 大连大学, 大连 116622 | | | 郭相金 | 辽宁省生物有机化学重点实验室, 大连大学, 大连 116622 | | | 张涛 | 大连大学生命科学与技术学院, 大连 116622 | | | 郑学仿 | 大连大学生命科学与技术学院, 大连 116622
辽宁省生物有机化学重点实验室, 大连大学, 大连 116622 | dlxfzheng@126.com |
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| 摘要: 细胞色素C(Cytochrome C,Cyt C)与NO(由NO供体药物proliNONOate提供)之间的反应已在电化学和医疗方面受到重视,而直接与NO气体作用尚未得到关注;且前者主要是从Q带进行分析的,Soret带未提及。本文采用紫外-可见(UV-Vis)吸收光谱、电子顺磁共振(EPR)光谱、紫外可见时间过程光谱以及同步荧光光谱等方法同时分析了其Soret带与Q带的变化,探讨了不同价态的Cyt C与NO气体结合及解离反应的过程。结果表明:Cyt C与NO相互作用时,无论是高铁细胞色素C(ferric cytochrome C,Fe(Ⅲ)-Cyt C)还是亚铁细胞色素C(ferrous cytochrome C,Fe(Ⅱ)-Cyt C),反应产物都是细胞色素C配合物(Cyt C-NO);Fe(Ⅱ)-Cyt C先被NO氧化生成Fe(Ⅲ)-Cyt C,之后再与NO结合生成Cyt C-NO,Fe(Ⅲ)-Cyt C则直接与NO结合生成Cyt C-NO。Cyt C-NO是一种不稳定的配合物,当通入少量NO时Cyt C-NO很快解离生成Fe(Ⅲ)-Cyt C,其解离速率为(0.005 07±0.001) s-1,是与供体药物结合所形成配合物解离速率的十分之一;NO过量时,生成的Cyt C-NO不会再发生解离。对实验结果分析,得出Cyt C与NO配位反应机制为溶液中的NO进入Heme腔内,Fe-S断裂,Fe-N间形成新的配位键,NO气体可以直接与Cyt C反应,生成的配合物比供体药物稳定,同时Soret带具有明显变化。这对于利用NO来缓解细胞内的氧化压以及利用NO检测细胞内呼吸类酶的变化,进而检测细胞凋亡具有重要意义。 |
| 关键词: 细胞色素C NO气体 光谱法 配位反应 解离 |
| 基金项目: 国家自然科学基金 (No.21271036, 20871024);辽宁省教育厅科学技术研究 (No.L2013470, L2013471)资助项目。 |
| Abstract: The research of cytochrome C (Cyt C) reacting with NO donor drugs(proliNONOate) has been focused on electrochemistry and medical treatment, while the study about reacting with NO gas is ignored. The previous study usually concentrated on Q band changes, but the Soret band was hardly mentioned. In this paper, we studied the reaction of two states of Cyt C with NO gas and the dissociation process by Soret band and Q band spectra, using ultraviolet-visible absorption spectra, electron paramagnetic resonance (EPR) spectra, ultraviolet-visible time course absorption spectra and synchronous fluorescence. The spectroscopic data showed that, ferric cytochrome C(Fe(Ⅲ)-Cyt C) and ferrous cytochrome C(Fe(Ⅱ)-Cyt C) could react with NO to convert to cytochrome C coordination compound(Cyt C-NO) with different mechanisms. Fe(Ⅱ)-Cyt C reacting with NO generated Fe(Ⅲ)-Cyt C firstly, then it combined with NO, while Fe(Ⅲ)-Cyt C can combine with NO directly. However, Cyt C-NO is not a stable coordinated macromolecule. With a small amount of NO bubbled into the sample, Cyt C-NO dissociated rapidly with rate constant value of (0.005 07±0.001) s-1, which is one-tenth of Cyt C-NO with NO donor drugs; while under excessive NO gas condition, the dissociation process was prevented. According to the experimental data, the coordination mechanism of the reaction between Cyt C and NO is that gas molecule gets access into the cavity of Heme, making the separation of Fe-S and the formation of Fe-N. Cyt C can react with NO gas directly, the Cyt C-NO is more stable than that reacted with NO donor drugs, and the Soret band have an obvious change. These results will be significant for us to remit the oxidative stress in cells and detect the respiratory enzymes change which could monitor the cell apoptosis and some diseases by NO. |
| Keywords: cytochrome c nitric oxide spectrometry coordination reaction dissociation |
| 投稿时间：2014-09-05 修订日期：2015-05-07 |
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| 唐乾,史珊珊,曹洪玉,郭相金,张涛,郑学仿.细胞色素C与NO的反应机制[J].无机化学学报,2015,31(8):1511-1519. |
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