Spectroscopic Studies on the Interaction of Fluorine Containing Triazole with Bovine Serum Albumin

The binding of one fluorine including triazole (C10H9FN4S, FTZ) to bovine serum albumin (BSA) was studied by spectroscopic techniques including fluorescence spectroscopy, UV-Vis absorption, and circular dichroism (CD) spectroscopy under simulative physiological conditions. Fluorescence data revealed that the fluorescence quenching of BSA by FTZ was the result of forming a complex of BSA-FTZ, and the binding constants (K-a) at three different temperatures (298, 304, and 310 K) were 1.516 x 10(4), 1.627 x 10(4), and 1.711 x 10(4) mol L-1, respectively, according to the modified Stern Volmer equation. The thermodynamic parameters Delta H and Delta S were estimated to be 7.752 kJ mol(-1) and 125.217 J mol(-1) K-1, respectively, indicating that hydrophobic interaction played a major role in stabilizing the BSA-FTZ complex. It was observed that site I was the main binding site for FTZ to BSA from the competitive experiments. The distance r between donor (BSA) and acceptor (FTZ) was calculated to be 7.42 nm based on the Forster theory of non-radioactive energy transfer. Furthermore, the analysis of fluorescence data and CD data revealed that the conformation of BSA changed upon the interaction with FTZ.