Interaction between Hydrophilic Proteins and Nonionic Detergents Studied by Surface Tension Measurements

Abstract

The surface tensions of the systems of hexa(oxyethylene) dodecyl ether (C12E6) vs. lysozyme (Lyz) or bovine serum albumin (BSA) were measured for constructing the binding isotherms, since the surface tension method is more convenient for the systems of nonionic detergents and proteins than is equilibrium dialysis. The obtained binding isotherms depend on the protein concentration; this effect is much more remarkable for Lyz–C12E6 systems than for BSA–C12E6 ones. The binding isotherms of BSA–C12E6 systems obey the Scatchard equation, and the maximum number and estimated free energy for C12E6 binding to BSA are comparable to those for the system of Triton X-100 and BSA determined by equilibrium dialysis. The agreement suggests that the surface tension method is sound and has advantages over equilibrium dialysis for the estimation of the number of detergent molecules bound to protein. In the systems of Lyz–C12E6, the binding isotherms follow the Freundlich-type equation rather than the Scatchard equation. The remarkable protein concentration dependence of the binding isotherms and this result suggest the occurrence of protein aggregation.

Physical and biophysical effects of polysorbate 20 and 80 on darbepoetin alfa

“…For rhGH and rhIG, 2-6 polysorbate molecules were bound to each protein with the number bound dependent on the hydrophobicity of the protein surface and the surfactant. 22 Similar conclusions regarding the hydrophobicity of the surfactants were reached by other investigators while studying the interactions between bovine serum albumin (BSA) and a variety of triton series surfactants by both surface tension 28 and ITC measurements. 29 The dissociation constants for these proteins determined by ITC measurements gave values in the mM to mM range.…”

“…10,[20][21][22][23][24][25][26][27][28][29][30][31] Helenius and Simons 30 compared the interactions of both Triton X-100 and deoxycholate micelles with several different lipophilic and hydrophilic proteins, and found that the hydrophilic proteins bound little or no surfactant. More extensive characterization and binding have recently been demonstrated for a small number of proteins including recombinant human growth hormone (rhGH), rhGH genetically fused to HSA, and recombinant human interferon gamma (rhIG).…”

Stabilization of human papillomavirus virus-like particles by non-ionic surfactants

“…It has been suggested that non-ionic surfactant molecules prevent protein denaturation at interfaces by winning the kinetic competition for binding at the interfaces. 45 Nishikido et al 22 pointed out that many hydrophilic proteins bind little or no non-ionic surfactants. For example, BSA binds with a maximum of 2-4 Triton X-100 molecules 46 and beta-lactoglobulin forms 1:1 complex with PS20 while Ovalbumin does not bind with TritonX-100.…”

Behavior of papain in mixed micelles of anionic–cationic surfactants having similar tails and dissimilar head groups

“…DS À and DDA + interacted with the positive and negative sites of polypeptide chain, respectively. On progressive addition of surfactant monomers, the adsorbed monomers continue to decrease c up to certain concentration known as cac, at which mixed surfactants and papain form aggregates (Region II) [25,26]. In this region, the configuration of the papain changed and the amphiphilic assemblies remained adhered to the polypeptide chain with partial depletion of Br À and Na + ions from their electrical double layer.…”