Yamanaka J, Inomata K, Yamagata Y
Department of Physics, Faculty of Science, Kanazawa University, Japan.
Orig Life Evol Biosph. 1988;18(3):165-78. doi: 10.1007/BF01804669.
The dehydration condensation of glycine with trimetaphosphate in aqueous solution has been reinvestigated. Although it has been reported that the condensation of glycine under the alkaline conditions was brought about through the formation of cyclic acylphosphoramidate and hence the condensation of polyglycines could not occur, we found that the condensation of oligoglycines with trimeta- and tetrametaphosphate in aqueous solution are possible through the formation of their acylphosphates under the neutral or weak acidic conditions. Aqueous solutions of 1.0 M glycylglycine and 1.0 M trimetaphosphate in the various pH from 4.0 to 9.0 were incubated at 38 degrees C. The solutions were analyzed by HPLC with ninhydrin reaction system. Tetraglycine and hexaglycine were detected and their maximum yields were given in the reaction carried out around pH 7. They are approximately 15% and 4% after 30 days, respectively. Analogous experiments were performed with tetrametaphosphate. The results showed a similar pH dependence for the condensation, but the yields were about one-tenth of those of corresponding experiments with trimetaphosphate. Relative rates of dimerization of glycine, diglycine and triglycine in the equimolar concentration were also investigated at pH 6.0 at 38 degrees C. The rates for diglycine and triglycine were approximately twice and four times as large as that for glycine. Relevance of the experiments to chemical evolution is discussed.
已对甘氨酸与三聚磷酸在水溶液中的脱水缩合进行了重新研究。尽管有报道称甘氨酸在碱性条件下的缩合是通过环状酰基磷酰胺的形成实现的，因此多聚甘氨酸的缩合无法发生，但我们发现，寡聚甘氨酸与三聚磷酸和四聚磷酸在水溶液中通过在中性或弱酸性条件下形成它们的酰基磷酸盐而实现缩合是可能的。将1.0 M甘氨酰甘氨酸和1.0 M三聚磷酸在pH值从4.0到9.0的各种水溶液在38℃下孵育。用茚三酮反应体系通过高效液相色谱对溶液进行分析。检测到了四聚甘氨酸和六聚甘氨酸，并且在pH约为7的反应中给出了它们的最大产率。30天后，它们分别约为15%和4%。用四聚磷酸进行了类似的实验。结果表明缩合反应对pH有类似的依赖性，但产率约为用三聚磷酸进行的相应实验的十分之一。在38℃、pH 6.0的条件下还研究了等摩尔浓度的甘氨酸、二甘氨酸和三甘氨酸的二聚化相对速率。讨论了这些实验与化学进化的相关性。
