Effect of Functional Groups on Incorporation Behavior of Amino Acid-Type Surfactant into Phospholipid Vesicle Membrane

Abstract

The incorporation behaviors of some N-dodecanoyl amino acid-type surfactants into L-adipalmitoylphosphatidylcholine (DPPC) vesicles in aqueous solution were investigated. From the leakage measurements of a vesicle-entrapped fluorescence probe, it was found that these surfactants did not affect the DPPC vesicle so much at a very low concentration less than a one-tenth of the critical micelle concentration (CMC), but caused a significant release of the probe form the vesicles even at just below the CMC. The leakage induced by amino acid-type surfactants was promoted by increasing hydrophobicity of the amino acid. However the polarization of DPH embedded in the DPPC membrane was almost unchanged by incorporation of the surfactants at the concentration below the CMC except for the Ndodecanoylphenylalanine system. The binding enthalpy and the binding constant of the surfactant to DPPC vesicles were estimated by isothermal titration calorimetry. While the binding enthalpy was independent of the kind of surfactant, the binding constant increases with increasing hydrophobicity of the amino acid species in the surfactants. The molar ratio of bound surfactant to DPPC molecule in the saturated state was much greater than that for sodium dodecyl sulfate system. Further the ratio was not influenced by the structure of the amino acid side chain.

Effect of Membrane Curvature Nanoarchitectonics on Membrane-Disruptive Interactions of Antimicrobial Lipids and Surfactants

“…On the other hand, our present results demonstrate that SDS micelles and monomers can solubilize relatively large, 120 nm diameter vesicles that have some degree of membrane curvature. This finding is consistent with a few past studies ,− that also indicate that SDS micelles and monomers can solubilize ca. >120 nm diameter vesicles.…”

Survey of the year 2009: applications of isothermal titration calorimetry

“…In 2009 we identified more than 400 articles after searching Web of Science, PubMed, SciDir and OVID databases using ‘isothermal AND titration AND calorimetry’ or ITC or ‘Isothermal Titration Calorimetry’ search terms. These have been classified into the following categories: Pre‐2009 references cited in the text and review articles 1–43 Protein‐protein and protein‐peptide interactions 44–124 Protein/peptide‐small molecule interactions 125–218 Protein/peptide‐metal ion interactions 219–253 Protein/peptide‐nucleic acid interactions 254–273 Protein/peptide‐lipid interactions 274–292 Protein/peptide‐polysaccharide interactions 293–316 Nucleic acid‐small molecule interactions 317–348 Small molecule interactions …”

Synthesis, physicochemical characterization and membrane interactions of a homologous series of N-acylserotonins: Bioactive, endogenous conjugates of serotonin with fatty acids

“…An important consequence of incorporating NASTs into phosphatidylcholine membranes would be its influence on the permeability of the vesicles. For example, it has been shown that incorporation of cholesterol into DMPC vesicles progressively reduces the leakage of carboxyfluorescein (CF) up to 30 mol% sterol [41], whereas N-dodecanoyl derivatives of amino acids such as glycine, valine, leucine and phenylalanine did not alter the permeability at low concentrations but led to complete leakage at concentrations close to their critical micellar concentrations [42]. The effect of incorporating NASTs on the permeability of phosphatidylcholine membranes can be assessed by monitoring the kinetics of the leakage of fluorescent probes such as CF or riboflavin that is loaded inside the vesicles [43,44].…”