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#detergent

4 public questions tagged with this topic.

Lipid Link Protein

What happens when detergent concentration is below the CMC?

Understanding CMC highlights phase behavior of amphiphiles. At subsaturation detergent monomers exist dissolved in aqueous phase hydration shell disordered, partial insertion into outer leaflet may increase permeability but leaves bilayer structure largely intact. When monomer concentration reaches thermodynamic threshold where entropic cost of ordering water around hydrophobic tails outweighs micellization free energy, spontaneous aggregation into micelles occurs with hydrocarbon tails sequestered interior and polar heads facing water forming spherical or ellipsoidal particles thirty to fifty

Ref: le Maire et al., Interaction of Membrane Proteins and Detergents, Biochim Biophys Acta 2000.

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Lipid Link Protein

Which of the following is a membrane-permeable detergent?

Detergent physicochemical properties determine permeabilization without denaturation. Triton X-100 tert-octylphenyl polyethoxyethanol consists of hydrophobic tert-octylphenol moiety and hydrophilic polyoxyethylene chain averaging nine to ten units, conferring CMC near zero point two four millimolar, aggregation number about one hundred to one fifty and micellar weight around ninety kilodalton. It partitions efficiently into phospholipid bilayers increasing permeability to macromolecules like antibodies and substrates, forming mixed micelles that solubilize lipids while protein-protein electros

Ref: Seddon et al., Methods Mol Biol, Membrane Protein Solubilization and Detergent Properties.

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Lipid Link Protein

What is the minimum amount of detergent needed for effective solubilization if the CMC is 5 mM?

Solubilization efficiency depends on detergent self-assembly thermodynamics above critical micelle concentration. Below CMC monomers dissolve individually with limited bilayer insertion causing minor perturbation without micelle formation. Above CMC cooperative aggregation produces spherical micelles of thirty to hundred monomers with hydrophobic core shielded and hydrophilic exterior, light scattering increases sharply and free monomer concentration remains near CMC. Micelles provide hydrophobic compartments that encapsulate lipids and transmembrane segments into water-soluble mixed micelles

Ref: Rosen and DeLisi, Detergent Properties and CMC in Membrane Protein Solubilization, Methods Enzymol.

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