The influence of heavy water as a solvent on the spontaneous oscillatory reactions of \u03b1-amino acids

Abstract

In our earlier investigations, we have discovered that α-amino acids dissolved in water or aqueous-organic solvents undergo spontaneous oscillatory chiral inversion and oscillatory peptidization in parallel, and the dynamics of these processes strongly depends on the chemical structure of a given amino acid, physicochemical characteristics of a solvent used, ambient temperature, etc. The aim of this study was to perform a preliminary reconnaissance on the possible impact of D2O on the dynamics of spontaneous behavior of the selected test α-amino acids (L-Phe, L-His, L-Pro and L-Cys) stored at 25 ± 0.5 °C for the period of 1 week. As the measuring techniques, turbidimetry in continuous registration mode and mass spectrometry were employed. For the sake of comparison, the analogous results were presented for the discussed α-amino acids dissolved in the aqueous organic solvents and originally published elsewhere. Based on a comparison of the turbidimetric fingerprints, the dynamics of the turbidity changes in heavy water have proved rather moderate. Mass spectrometric results provided a confirmatory evidence witnessing to rather negligible peptide yields in heavy water. Thus, turbidimetric and mass spectrometric data have served as complementary proofs of a considerable hampering of spontaneous peptidization of α-amino acids in D2O.