The investigation of the interaction between Tropicamide and bovine serum albumin by spectroscopic methods

The fluorescence and ultraviolet-visible (UV-Vis) spectroscopy were explored to study the interaction between Tropicamide (TA) and bovine serum albumin (BSA) at three different temperatures (292, 301 and 310 K) under imitated physiological conditions. The experimental results showed that the fluorescence quenching mechanism between TA and BSA was static quenching procedure. The binding constant (K-a), binding sites (n) were obtained. The corresponding thermodynamic parameters (Delta H, Delta S and Delta G) of the interaction system were calculated at different temperatures. The results revealed that the binding process is spontaneous, hydrogen binds and vander Waals were the main force to stabilize the complex. According to Forster non-radiation energy transfer theory, the binding distance between TA and BSA was calculated to be 4.90 nm. Synchronous fluorescence spectroscopy indicated the conformation of BSA changed in the presence of TA. Furthermore, the effect of some common metal ions (Mg2+, Ca2+, Cu2+, and Ni2+) on the binding constants between TA and BSA were examined. (C) 2013 Elsevier B.V. All rights reserved.