The Origin of Metabolism and Heredity

生命的自养起源越来越获得实验的支持。非酶的等价物已经存在于所有生命中保守的代谢的核心部分，包括糖酵解，异生，克雷布斯和乙醛酸循环。这种仿生途径不适用于嘌呤和相关辅因子，尽管有证据表明它们在生长原始细胞和遗传信息起源中的重要性。类似地，核苷酸聚合和自养来源的相容性尚未在实验上得到证实。嘌呤从头合成途径以前的调查尚未取得丰硕成果，在水溶剂中，然而，使用HPLC-MS，鉴定不稳定的中间体和那些没有化学标准品现在可能是可行的。辅助因子吡哆醛和NMN的仿生合成将实验性地将氨基酸的产生与克雷布斯循环中间体联系起来：这些辅助因子也可能是形成嘌呤所必需的。使用氨基酸和短肽辅因子聚合RNA核苷酸将是开发能够利用化学网络失衡的遗传信息的第一步。对这些反应可能发生的化学条件的研究利用了多种方法，包括HPLC-MS、GC-MS、NMR光谱和IR光谱。

An autotrophic origin for life is increasingly gaining experimental plausibility. Nonenzymatic equivalents already exist for core parts of metabolism conserved in all life, including glycolysis, gluconeogenesis, Krebs and glyoxylate cycles. Such biomimetic pathways are not available for purines and related cofactors, despite evidence to suggest their importance in growing protocells and at the origin of genetic information. Similarly, the compatibility of polymerisation of nucleotides and an autotrophic origin has not yet been experimentally demonstrated. Previous investigations into the purine de novo synthesis pathway have not yet yielded fruitful results in aqueous solvents; however, with the use of HPLC-MS, the identification of unstable intermediates and those without chemical standards may now be feasible. The biomimetic synthesis of the cofactors, pyridoxal and NMN, would experimentally link the production of amino acids to Krebs cycle intermediates: these cofactors may also be necessary for the formation of purines. Polymerisation of RNA nucleotides using amino acid and short peptide cofactors would be the first step in the development of genetic information capable of exploiting a chemical network out of equilibrium. Investigation into the chemical conditions in which these reactions are possible utilises a variety of methods including HPLC-MS, GC-MS, NMR spectroscopy and IR spectroscopy.