Plasson R, Biron J Ph, Cottet H, Commeyras A, Taillades J
Laboratoire Organisation Moléculaire, Evolution et Matériaux Fluorés, UMR 5073, Université Montpellier II, France.
J Chromatogr A. 2002 Apr 5;952(1-2):239-48. doi: 10.1016/s0021-9673(02)00018-3.
N-Carboxyanhydrides of amino acids (NCAs) are very reactive monomers able to polymerize into oligopeptides. They are assumed to be prebiotic precursors of the first polypeptides. Few reports have been published on the study of NCA polymerization in aqueous solution. In this work, a kinetic study focused on the hydrolysis of NCA and its coupling with amino acids and homopeptides (up to tripeptide) was carried out, taking L-valine derivatives as model compounds. For that purpose, capillary electrophoresis appeared to be an effective and reliable technique for the measurement of the kinetic constants. The electrophoretic separation conditions, the procedure for stopping NCA reactivity, as well as the conditions of reaction are discussed in detail. We report the variation of the kinetic constant of the coupling reaction of the NCA of valine with an oligovaline as a function of its degree of polymerization. Finally, a temperature study also allowed us to estimate the activation energies associated with the NCA of valine hydrolysis and its coupling reaction with valine.
氨基酸N - 羧基酸酐（NCAs）是非常活泼的单体，能够聚合成寡肽。它们被认为是首批多肽的前体物质。关于NCA在水溶液中聚合反应的研究报道很少。在这项工作中，以L - 缬氨酸衍生物作为模型化合物，开展了一项动力学研究，重点关注NCA的水解及其与氨基酸和同型肽（直至三肽）的偶联反应。为此，毛细管电泳似乎是测量动力学常数的一种有效且可靠的技术。详细讨论了电泳分离条件、终止NCA反应活性的步骤以及反应条件。我们报道了缬氨酸NCA与寡聚缬氨酸偶联反应的动力学常数随其聚合度的变化情况。最后，一项温度研究还使我们能够估算与缬氨酸NCA水解及其与缬氨酸偶联反应相关的活化能。
