Lipid bilayers in the gel phase become saturated by triton X-100 at lower surfactant concentrations than those in the fluid phase.
It has been repeatedly observed that lipid bilayers in the gel phase are solubilized by lower concentrations of Triton X-100, at least within certain temperature ranges, or other nonionic detergents than bilayers in the fluid phase. In a previous study, we showed that detergent partition coefficients into the lipid bilayer were the same for the gel and the fluid phases. In this contribution, turbidity, calorimetry, and 31P-NMR concur in showing that bilayers in the gel state (at least down to 13-20°C below the gel-fluid transition temperature) become saturated with detergent at lower detergent concentrations than those in the fluid state, irrespective of temperature. The different saturation may explain the observed differences in solubilization.
Unidad de Biofísica (Centro Mixto CSIC-UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain.
Hasna
H
Ahyayauch
M Isabel
MI
Collado
Alicia
A
Alonso
Felix M
FM
Goñi
D005782:Gels / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D017830:Octoxynol / Q000494:pharmacology*; D044367:Phase Transition / Q000187:drug effects*; D010713:Phosphatidylcholines / Q000737:chemistry; D012212:Rheology / Q000187:drug effects*; D012995:Solubility / Q000187:drug effects; D013109:Sphingomyelins / Q000737:chemistry; D013501:Surface-Active Agents / Q000494:pharmacology*; D013696:Temperature; D053835:Unilamellar Liposomes / Q000737:chemistry
D005782:Gels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D013109:Sphingomyelins; D013501:Surface-Active Agents; D053835:Unilamellar Liposomes; D017830:Octoxynol