Interaction Between Levamisole Hydrochloride and Bovine Serum Albumin and the Influence of Alcohol: Spectra

The interaction between levamisole hydrochloride (LH) and bovine serum albumin, BSA, has been studied by a spectral method under physiological conditions. For 1:n complexes, the relationship between fluorescence quenching intensity and concentration of the quenchers can be deduced on the basis of the modified Stern-Volmer equation. The binding constants and corresponding thermodynamic parameters Delta H (m), Delta G (m) and Delta S (m) at different temperatures were calculated. The experimental results demonstrated that the combination reaction of LH and BSA was a static quenching process because a 1:1 complex was formed, and the main dominant binding forces were hydrogen bonding and van der Waals forces. Meanwhile, the polarity of the tyrosine residue (Tyr) or tryptophan residue (Trp) micro-region was not obviously affected by the interaction. Furthermore, the binding constant increase when alcohol was added.