The Interactions between Quaternary Ammonium Cationic Surfactants and Bovine Serum Albumin

Abstract

UV-visible (UV-Vis) absorption spectroscopy, fluorescence spectroscopy (FL), dynamic light scattering (DLS) and isothermal titration calorimetry (ITC) were used to study the interactions between bovine serum albumin (BSA) and the three quaternary ammonium surfactants N-dodecyl-N-(2-hydroxyethyl)-N,Ndimethyl ammonium bromide (DHDAB), N-tetradecyl-N-(2-hydroxyethyl)-N,N-dimethyl ammonium bromide (THDAB) and N-cetyl-N-(2-hydroxyethyl)-N,N-dimethyl ammonium bromide (CHDAB). These surfactants quenched the intrinsic fluorescence of BSA, with longer alkyl chains resulting in more significant quenching. This was attributed to static quenching. Further evidence of static quenching was provided by UV-Vis absorption spectroscopy. The particle size of BSA was found to initially increase and then decrease with increasing surfactant concentration. The concentration of surfactant changed the type of interaction mode. This work revealed the mechanism and binding characteristics between surfactants and protein, and provides the basis

Physicochemical study of biomolecular interactions between lysosomotropic surfactants and bovine serum albumin

“…The fluorescence intensity of Trp residues was significantly higher than that of Tyr residues, indicating that the main contribution of the intrinsic fluorescence of BSA is due to the Trp residues, thus DMM-11 and DMPM-11 mainly interact with Trp residues of BSA. These results are similar to those reported for the fluorescence intensity changes of BSA with quaternary ammonium cationic surfactants [39]. Furthermore, Wu and co-workers observed that the fluorescence intensity increases significantly with the increase of cationic gemini surfactants concentrations, when was set at 20 nm [31].…”