Interaction between bovine serum albumin and equimolarly mixed cationic-anionic surfactants decyltriethylammonium bromide-sodium decyl sulfonate.
The interactions of bovine serum albumin (BSA) with the anionic surfactant sodium decylsulfonate (C10SO3), the cationic surfactant decyltriethylammonium bromide (C10NE) and equimolarly mixed cationic-anionic surfactants C10NE-C10SO3 were investigated by surface tension, viscosity, dynamic light scattering (DLS) and circular dichroism (CD). It was shown that the single ionic surfactant C10SO3 or C10NE has obvious interaction with BSA. The presence of C10SO3 or C10NE modified BSA structure. However, the equimolarly mixed cationic-anionic surfactants C10NE-C10SO3 showed very weak interactions with BSA. The surface tension-log concentration (gamma-logC) plot for the aqueous solutions of C10NE-C10SO3/BSA mixtures coincided with that of C10NE-C10SO3 solutions. Viscometry showed that there is no significant change in the rheological properties for the C10NE-C10SO3/BSA mixed solutions. DLS showed that BSA monomers and mixed aggregates of C10NE-C10SO3 existed in the C10NE-C10SO3/BSA mixed solutions. From CD spectra no obvious modification of BSA structure in the presence of C10NE-C10SO3 mixtures was observed. The weak interactions between BSA and C10NE-C10SO3 might be explained in terms of the very low critical micelle concentration (cmc) of C10NE-C10SO3 mixtures that made the concentration of ionic surfactant monomers much lower than that needed for inducing the modification of BSA structure. In other words, the very strong synergism between oppositely charged cationic and anionic surfactants makes the formation of cationic-anionic surfactant mixed aggregates in the bulk solution a more favorable process than binding to proteins.
Lu
Run-Chao
RC
College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
Cao
Ao-Neng
AN
Lai
Lu-Hua
LH
Zhu
Bu-Yao
BY
Zhao
Guo-Xi
GX
Xiao
Jin-Xin
JX
D000838:Anions; D001557:Benzenesulfonates / Q000737:chemistry; D002412:Cations; D002942:Circular Dichroism; D007700:Kinetics; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012996:Solutions; D013500:Surface Tension; D013501:Surface-Active Agents
D000838:Anions; D001557:Benzenesulfonates; D002412:Cations; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D013501:Surface-Active Agents; C013912:decyltrimethylammonium; D012710:Serum Albumin, Bovine; C001114:dodecylbenzenesulfonic acid