Cold physical plasma-induced oxidation of cysteine yields reactive sulfur species (RSS)
Cold physical plasma-induced oxidation of cysteine yields reactive sulfur species (RSS)
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DOI：
10.1016/j.cpme.2019.100083
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发表时间：
2019-06-01
影响因子：
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通讯作者：
Wende, Kristian
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文献类型：
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作者：
Bruno, Giuliana;Heusler, Thea;Wende, Kristian
目的：研究血浆液体化学可以揭示其生物医学效应，即了解治疗在模型或临床应用中触发的直接和间接过程。由于硫原子的反应性，硫醇是等离子体衍生反应物种的潜在目标。作为蛋白质功能和氧化还原信号通路的关键，它们的可控修饰将扩大其应用范围。此外，控制和标准化CAP源的模型是等离子体源设计的理想工具。方法：利用半胱氨酸作为示踪剂，清除Ar等离子体射流产生的活性物种。通过高分辨质谱学鉴定了产物的图谱。Ellman‘s法用于筛选CAP衍生的硫醇消耗，并监测与半胱氨酸存在相关的长寿命物种沉积(过氧化氢、亚硝酸盐、硝酸盐)。结果：半胱氨酸氧化强度随处理时间和原料气中氧气供应的增加而增加。确定了半胱氨酸的一系列产品，部分表明了某些治疗条件。在等离子体处理过程中，会产生几种不稳定的产物。在温和的处理条件下，如半胱氨酸亚砜和半胱氨酸S磺酸盐，已经发现了生物活性活性硫物种。考虑到边界层中半胱氨酸分子的数量和达到的氧化状态，短寿命物种在半胱氨酸转化过程中占主导地位。此外，还观察到示踪剂的边界层耗尽。结论：将这些数据转化为体内应用，必须考虑蛋白质硫醇基团的强烈直接氧化，从而导致蛋白质生物化学的变化。血浆来源的RSS可能在一定程度上有助于观察到CAP的生物医学效应。必须注意严格控制放电参数，因为液体中或液体中的化学动力学很容易发生变化。
Purpose: Studying plasma liquid chemistry can reveal insights into their biomedical effects, i.e. to understand the direct and indirect processes triggered by the treatment in a model or clinical application. Due to the reactivity of the sulfur atom, thiols are potential targets for plasma-derived reactive species. Being crucial for protein function and redox signaling pathways, their controllable modification would allow expanding the application range. Additionally, models to control and standardize CAP sources are desired tools for plasma source design. Methods: Cysteine, a ubiquitous amino acid, was used as a tracer compound to scavenge the reactive species produced by an argon plasma jet (kINPen). The resulting product pattern was identified via high-resolution mass spectrometry. The Ellman's assay was used to screen CAP derived thiol consumption, and long-lived species deposition (hydrogen peroxide, nitrite, nitrate) was monitored in relation to the presence of cysteine. Results: The intensity of cysteine oxidation increased with treatment time and availability of oxygen in the feed gas. A range of products from cysteine was identified, in part indicative for certain treatment conditions. Several non-stable products occur transiently during the plasma treatment. Bioactive reactive sulfur species (RSS) have been found for mild treatment conditions, such as cysteine sulfoxides and cysteine-S-sulfonate. Considering the number of cysteine molecules in the boundary layer and the achieved oxidation state, short-lived species dominate in cysteine conversion. In addition, a boundary layer depletion of the tracer was observed. Conclusion: Translating these data into the in-vivo application, strong direct oxidation of protein thiol groups with subsequent changes in protein biochemistry must be considered. Plasma-derived RSS may in part contribute to the observed biomedical effects of CAP. Care must be taken to control the discharge parameter tightly as chemical dynamics at or in the liquid are subject to change easily.