Spectral Studies On the Interaction of Toluidine Blue O With Bovine Serum Albumin

Interaction between toluidine blue O (TBO) and bovine serum albumin (BSA) was investigated by UV-visible absorption and emission spectroscopy. It is proposed that the fluorescence quenching of BSA by TBO was mainly a result of the formation eof TBO-BSA complex and electrostatic interactions played an important role to stabilize the complex. The Stern-Volmer quenching constant K_SV and corresponding thermodynamic parameters ΔH⁰, ΔG⁰, and ΔS⁰ were evaluated. Results suggest the interaction process to be comparable with the reversible biological processes. Effect of TBO on the conformation of BSA has been analyzed by means of synchronous fluorescence spectroscopy. IR spectra also proved that the interaction of TBO with BSA had changed the conformation of TBO.