The Role of Submarine Hydrothermal Systems in the Synthesis of Amino Acids
The Role of Submarine Hydrothermal Systems in the Synthesis of Amino Acids
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DOI：
10.1007/s11084-008-9153-2
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发表时间：
2009-04-01
影响因子：
2
通讯作者：
Bada, Jeffrey L.
中科院分区：
文献类型：
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作者：
Aubrey, A. D.;Cleaves, H. J.;Bada, Jeffrey L.
关于海底热液系统（SHS）中有机合成的合理性及其与生命起源的可能相关性，几乎没有达成共识。这场争论持续存在的主要原因是大多数实验高温高压有机合成研究忽略了与源材料成分有关的重要地球化学限制。我们在这里报告了探索在高温下从不同成分的合成海水溶液合成氨基酸的潜力的实验结果。检查氨基酸的合成作为温度、加热时间、起始材料组成和浓度的函数。使用非常有利的反应物条件（高浓度的反应性还原物质），在中等温度条件（类似于 125-175A 摄氏度）下，经过几天的短加热时间，会生成少量有限的一组氨基酸，但即使这些产物在暴露时间大约 1 周后也会显着分解。浓度降低 10 倍会导致氨基酸产量降低几个数量级，这一事实证明了这些合成反应观察到的高度浓度依赖性。可能还有其他本文未研究的合成机制值得研究，但结果可能是相似的。我们的结论是，虽然在 SHS 条件下可以从简单的可能环境可用的前体生成氨基酸，但 SHS 的高温平衡特征有利于氨基酸的净降解而不是合成，并且在较低温度下的合成可能更有利。
There is little consensus regarding the plausibility of organic synthesis in submarine hydrothermal systems (SHSs) and its possible relevance to the origin of life. The primary reason for the persistence of this debate is that most experimental high temperature and high-pressure organic synthesis studies have neglected important geochemical constraints with respect to source material composition. We report here the results of experiments exploring the potential for amino acid synthesis at high temperature from synthetic seawater solutions of varying composition. The synthesis of amino acids was examined as a function of temperature, heating time, starting material composition and concentration. Using very favorable reactant conditions (high concentrations of reactive, reduced species), small amounts of a limited set of amino acids are generated at moderate temperature conditions (similar to 125-175A degrees C) over short heating times of a few days, but even these products are significantly decomposed after exposure times of approximately 1 week. The high concentration dependence observed for these synthetic reactions are demonstrated by the fact that a 10-fold drop in concentration results in orders of magnitude lower yields of amino acids. There may be other synthetic mechanisms not studied herein that merit investigation, but the results are likely to be similar. We conclude that although amino acids can be generated from simple likely environmentally available precursors under SHS conditions, the equilibrium at high temperatures characteristic of SHSs favors net amino acid degradation rather than synthesis, and that synthesis at lower temperatures may be more favorable.