Oxidative modification of cytochrome c by singlet oxygen
Oxidative modification of cytochrome c by singlet oxygen
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DOI：
10.1016/j.freeradbiomed.2007.12.031
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发表时间：
2008-05-01
影响因子：
7.4
通讯作者：
Anderson, Vernon E.
中科院分区：
文献类型：
--
作者：
Kim, Junhwan;Rodriguez, Myriam E.;Anderson, Vernon E.
单线态氧（O-1（2））是一种活性氧，可在生物系统中产生。光动力疗法通过光敏剂的光激发产生O-1（2），导致细胞内氧化应激和诱导细胞凋亡。O-1（2）氧化蛋白质的氨基酸侧链，并在体外产生时使酶失活。在蛋白质氨基酸中，已知His、Tyr、Met、Cys和Trp在生理pH下被O-1氧化（2）。然而，缺乏O-1氧化蛋白质的直接证据（2）。由于O-1（2）在细胞中很难检测到，因此鉴定O-1（2）独特的氧化细胞产物可以作为其存在的标志。在本研究中，通过串联质谱分析与模型肽的O-1（2）反应提供了对与反应性氨基酸形成的主要加合物质量的深入了解。通过MALDI-TOF和串联质谱法分析了酞菁Pc 4光激发产生的O-1（2）对细胞色素c肽段的影响，发现了独特的氧化产物，这可能是O-1（2）存在于线粒体膜间隙的标志。细胞色素c和模型肽观察到的氧化氨基酸残基的元素组成的差异表明，蛋白质环境可以影响氧化途径。(c)2007爱思唯尔公司All rights reserved.
Singlet oxygen (O-1(2)) is a reactive oxygen species that may be generated in biological systems. Photodynamic therapy generates O-1(2) by photoexcitation of sensitizers resulting in intracellular oxidative stress and induction of apoptosis. O-1(2) Oxidizes amino acid side chains of proteins and inactivates enzymes when generated in vitro. Among proteogenic amino acids, His, Tyr, Met, Cys, and Trp are known to be oxidized by O-1(2) at physiological pH. However, there is a lack of direct evidence of oxidation of proteins by O-1(2). Because O-1(2) is difficult to detect in cells, identifying oxidized cellular products uniquely derived from O-1(2) could serve as a marker of its presence. In the present study, O-1(2) reactions with model peptides analyzed by tandem mass spectrometry provide insight into the mass of prominent adducts formed with the reactive amino acids. Analysis by MALDI-TOF and tandem mass spectrometry of peptides of cytochrome c exposed to O-1(2) generated by photoexcitation of the phthalocyanine Pc 4 showed unique oxidation products, which might be used as markers of the presence Of O-1(2) in the mitochondrial intermembrane space. Differences in the elemental composition of the oxidized amino acid residues observed with cytochrome c and the model peptides suggest that the protein environment can affect the oxidation pathway. (c) 2007 Elsevier Inc. All rights reserved.