Interaction between bovine serum albumin and equimolarly mixed cationic脙脙脙脙脙脙anionic surfactants decyltriethylammonium bromide脙脙脙脙脙脙sodium decyl sulfonate

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• 作者：Lu ; Run-Chao ; Cao ; Ao-Neng ; Lai ; Lu-Hua ; Zhu ; Bu-Yao ; Zhao ; Guo-Xi ; Xiao ; Jin-Xin
• 关键词：Cationic脙脙脙脙脙脙anionic surfactants ; Protein脙脙脙脙脙脙surfactant interactions ; Bovine serum albumin ; Surface tension ; Circular dichroism
• 刊名：Colloids and Surfaces B ; Biointerfaces
• 出版年：2005
• 期刊代码：14_09277765
• 类别：ms
• 出版时间：March 25, 2005
• 卷：41
• 期：2-3
• 页码：139-143
• 文件大小：284 K

摘要

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 (γ–log C) 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.