Ternary Amino Acid Metal Complexes: Structure and Role in Yeast Metabolism

Abstract

Two ternary complexes designated as Ter1 and Ter2 were synthesized using minimal optimal methods wherein two separate amino acid ligands L-phenylalanine and L-lysine were mixed with chromium sulphate hexahydrate designated as Cr3+ and two routes were designed for the synthesis of both the complexes. For the synthesis of Ter1 L-phenylalnine was reacted with Cr3+ which was in turn reacted with L-lysine and for the synthesis Ter2 the reverse procedure was adopted L-lysine was reacted with Cr3+ which was in turn reacted with L-phenylalanine. IR spectral analysis of the two complexes showed that they were isomeric complexes with a different orientation of ligands around chromium and the UV-VIS spectra of both the ternaries showed that the way in which phenylalanine interacted with chromium was same and the difference was only in the way of binding of L-lysine with difference in the absorption peaks which was another indication that the two complexes are different. As regards the biological role of the two ternaries, even though superficially both were almost similar in the way in which they were metabolized as nitrogen sources, on closer examination it was observed That L-phenylalanine was metabolized at a much faster rate than L-lysine especially in Ter2, and it was shown that the structure of Ter2 is different from that of Ter1 since in Ter2 L-lysine is more tightly bound to central chromium vis-à-vis Ter1 and this corroborates with the biological activity. Thus a direct correlation is brought about between the structure of the ternary complexes and their biological activity. This study is the first of its type and draws light on the fact that a more holistic approach should be considered as regards the biological activity of chromium amino acid complexes as regards to yeast metabolism.
Keywords: Saccharomyces cerevisiae , Ter1, Ter2, Metal Complexes, AA-Cr