SPONTANEOUSE OSCILLATORY REACTION OF PROTEIN AMINO ACIDS IN ABIOTIC SYSTEM – LC-MS RESULTS Anna Maciejowska, Agnieszka Godziek, Mieczysław Sajewicz, Teresa Kowalska Institute of Chemistry, University of Silesia, 9 Szkolna Street, Katowice, Poland INTRODUCTION In previous studies, it has been shown that low molecular weight chiral compounds belonging to the group of profen drugs [1], amino acids [2], and hydroxy acids [3] can undergo spontaneous oscillatory reactions in solution. These spontaneous reactions are characteristic of single and mixed components dissolved in aqueous and non-aqueous solvents. In this experiment, we focus our attention on a pair of amino acids (L- histidine and L-threonine). The choice of these two amino acids was due to their important functions in living organisms. L-Thr is essential in the synthesis of proteins, contributing to the growth and development of the muscles. It also affects the production of elastin and collagen, improves the condition of joints, tendons and skin. It also supports proper functioning of nervous system. L-His acts as a precursor of histamine and it plays a a key role in active centers of many enzymes. AIM The aim of this study was to compare the oscillatory reactions of two amino acids (L-Thr and L-His) in monocomponent solutions and in a binary solution (L-Thr – L-His). EXPERIMENTAL Analyzed samples: L-Thr, L-His, L-Thr-L-His (c = 1 mg mL -1 ) HPLC: The Varian (model 920) liquid chromatograph; the C-18 column (ThermoQuest Hypersil, 150 mm × 4.6 mm i.d., 5 µm particle size); the 8-μL aliquots of the investigated amino acid solution, ELSD detector, mobile phase: methanol-water (20:80, v/v); flow rate: 0.8 mL min -1. HPLC-MS: The Varian MS-100 mass spectrometer (ESI-MS scan from m/z 100 to 2000, positive ionization); Figure 2. Mechanism of the parallel oscillatory chiral conversion and oscillatory peptidization of amino acids a) b) c) Figure 3. Changes of chromatographic peak heights (the ELSD detector) as a function of storage time of : a) L-His; b) L-Thr; and c) L-Thr-L-His a) b) c) Figure 4. The HPLC-MS chromatograms and the respective mass spectra recorded from the aged sample of a) L-Thr; b) L-His; and c) L-His-LThr a) b) c) d) e) Figure 1. Chemical structures of amino acids: a) L-Thr; b) L-His, and the dipeptides : c) L-Thr-L-His; d) L- Thr-L-Thr; e) L-His-L-His References [1] M. Sajewicz, R. Piętka, A. Pieniak, T. Kowalska; Acta Chromatogr, 15, (2005) [2] M. Sajewicz, D. Kronenbach, M. Gontarska, M. Wróbel, R. Piętka, T. Kowalska, J. Planar Chromatogr., 22, (2009) [3] M. Sajewicz, D. Kronenbach, M. Gontarska, T. Kowalska, J. Liq. Chrom. Rel. Technol., 31, (2010) [4] M. Sajewicz, M. Dolnik, T. Kowalska, I. R. Epstein, RSC Adv., 4, 7330–7339 (2014) RESULT AND DISCUSSION The obtained results indicate an occurrence of the oscillatory peptidization with the investigated amino acids. The HPLC analysis shows different dynamics of oscillatory processes of amino acids. The dynamics of these processes is dependent on whether there were the monocomponent or binary solutions thereof. The results of the HPLC / MS analysis confirmed an appearance of peptides. L-His L-Thr