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

Abstract

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 ΔHm, ΔGm and ΔSm 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.