Surfactant and Temperature Effects in Tyrosine/Pyridoxine Hydrochloride Systems

Abstract

The fluorescence resonance energy transfer (FRET) from tyrosine to pyridoxine hydrochloride in different surfactant solutions and in deionized water has been investigated by using a fluorescence spectroscopic technique. The Stern-Volmer quenching constant, the distance between donor (tyrosine) and acceptor (pyridoxine hydrochloride), and the energy transfer efficiency were obtained using the Stern-Volmer relation and Forster's theory of nonradiative energy transfer. The data obtained from the measurement reveals that the FRET occurs more effectively in aqueous SDS micellar solution than in CTAB or linear alcohol ethoxylate micellar systems and deionized water. Moreover, the binding constant, number of binding sites, and thermodynamic parameters DG, DH, DS were obtained by studying the tyrosine-pyridoxine hydrochloride interactions at three different temperatures. The decrease in binding constant with temperature reflects the existence of weak interaction between tyrosine and pyridoxine hydrochloride at high temperature. The analysis confirms that van der Waals forces and hydrogen bonding are involved in the interaction.