[Study on the interaction between methylene blue and bovine serum albumin by fluorescence spectroscopy]

The binding characteristics of methylene blue (MB) and bovine serum albumin (BSA) has been studied by fluorescence spectroscopy in aqueous solution. The results show that the equilibrium constant KA = 3.44 x 10(5) L.mol-1, the number of binding sites n = 1.03, and the quenching mechanism of fluorescence of BSA by MB is a static quenching procedure. The binding distance between MB and BSA and the energy transfer efficiency are obtained based on the theory of Förester spectroscopy energy transfer. The effect of MB on the conformation of BSA is further analyzed using synchronous fluorescence spectrometry.