Spectroscopic Study of the Interaction between Sulfamethoxazole and Bovine Serum Albumin in the Presence of Fe 3

Under the simulative human physiological condition, the interaction of sulfamethoxazole (SMZ) and bovine serum albumin (BSA) with or without Fe 3 + was studied by fluorescence spectra, ultra-violet ab- sorption spectra and FT-IR spectra. The results show that both the quenching mechanism of the intrinsic fluorescence of BSA by sulfamethoxazole with or without Fe 3 + is a static fluorescence quenching proce- dure. It was found that in the presence of Fe 3 + , the binding constant of SMZ and BSA increased and the main binding force between SMZ and BSA was changed from hydrophobic force to hydrogen bonds and van der Waals force. From the synchronous fluorescence and three-dimensional fluorescence spectra, it was found that SMZ change the conformation of BSA. BSA may form a new disordered structure, but the capa- bility of SMZ changing the structure of the BSA was not enhanced in the presence of Fe 3 + . Based on fluo-