Detergent micelle

Stigter, D, Kinetic Charge of Colloidal Electrolytes from Conductance and Electrophoresis. Detergent Micelles, Poly(methacrylates), and DNA in Univalent Salt Solutions, Journal of Physical Chemistry 83, 1670, 1979. 

In the bilayer or upon interaction with detergent micelles, a structural reorganization of pardaxin aggregates takes place, in which the polar side chains interact with themselves and the hydrophobic residues are externally oriented in the pardaxin aggregate, therefore allowing interactions with the lipid backbone hydrocarbons. 

HPCE separations utilizing the MEKC mode allow the electrophoretic separations of neutral components using detergent micelles. The advantage of using detergents is that in most cases the sample cleanup and solubilization step can be eliminated because of the presence of the detergent. Penicillins,112113... 

For comparison, included in Table 14.3 are the kq values obtained in detergent micelles along with kq values obtained in homogeneous solvent benzene. As can be seen, the second-order rate constant for 02 quenching in a liposomal environment is a factor of 4 lower for (3-CAR compared to the second-order rate constant obtained in the aromatic solvent. While, there is a marked 80-130 fold difference between the kq values determined in liposomal environments compared to the kq values determined in the aromatic solvent for the XANs. 

Second-Order Rate Constants for the Repair of Carotenoid Radical Cations by Four Biologically Relevant Molecules in Triton Detergent Micelles... 

Fluorescent silica nanoparticles, called FloDots, were created by Yao et al. (2006) by two synthetic routes. Hydrophilic particles were produced using a reverse micro-emulsion process, wherein detergent micelles formed in a water-in-oil system form discrete nanodroplets in which the silica particles are formed. The addition of water-soluble fluorescent dyes resulted in the entrapment of dye molecules in the silica nanoparticle. In an alternative method, dye molecules were entrapped in silica using the Stober process, which typically results in hydrophobic particles. Either process resulted in luminescent particles that then can be surface modified with... 

Fig. 5 Membrane models for NMR structure analysis, (a) An isotropic detergent micelle (left) is compared to the dimensions of lipid bilayers (right), (b) Macroscopically oriented membrane samples can be prepared on solid support, as nanodiscs, or as magnetically oriented bicelles. (c) Nomenclature and variability of liposomes small (SUV, 20-40 nm), intermediate (IUV, 40-60 nm), large (LUV, 100-400 nm), and giant unilamellar vesicles (GUV, 1 pm) multi-lamellar (MLV), oligo-lamellar (OLV) and highly heterogeneous multi-oligo-lamellar vesicles (MOLV)...

Fernandez C, Wuthrich K (2003) NMR solution structure determination of membrane proteins reconstituted in detergent micelles. FEBS Lett 555 144-150... 

At their critical micelle concentrations, surface active agents (such as sodium dodecyl sulfate, Triton X-100, lysolecithin, and bile salts) self-associate into spherical or rod-shaped structures. Because dilution to below the c.m.c. results in rapid disassembly or dissolution of these detergent micelles, micelles are in dynamic equilibrium with other dissolved detergent molecules in the bulk solution. 

SOLVENT EFFECTS ZWiTTERGENTS DETERGENTS MICELLE ZWITTERION ZYMOGEN Zymogen activation,... 

Hemes encapsulated in aqueous detergent micelles find themselves in a large macromolecular cavity whose interaction is mainly hydrophobic. It has been suggested that such systems appear to simulate the electrostatic and hydrophobic interactions of the heme cavity in metalloproteins. The present article surveys reported studies on natural and synthetic hemes, both ferric and ferrous, incorporated inside micelles of different sizes and surface charges. The emphasis is laid on multinuclear NMR and optical spectroscopic studies. The effect of micellar interactions on the electronic properties of hemes is discussed and compared with that of the heme cavity in proteins. 

It has been suggested that aqueous micellar systems simulate the electrostatic and hydrophobic interactions of the heme cavity [15-23]. Pioneering studies by Simplicio et al. [15-17] have shown that the heme is monodispersed when encapsulated in aqueous micelles. They have studied binding of cyanide and other axial ligands to ferric hemes in micellar environments. These studies [15-23] indicated that a heme encapsulated in an aqueous detergent micelle finds itself inside a large macromolecular cavity whose interactions is primarily... 

The purpose of this article is to review studies carried out on hemes incorporated inside the micellar cavity, and examine the effect of micellar interaction on the electronic and structural properties of the heme. A comparison of these results with those on the metalloproteins is clearly in order to assess their suitability as models. The article begins with a general introduction to micellar properties, the incorporation of hemes in the micellar cavity, and then discusses results on hemes inside the micelles with different oxidation and spin states, and stereochemistry. The experimental techniques used in the studies on these aqueous detergent micelles are mostly NMR and optical spectroscopy. The present article has therefore a strong emphasis on NMR spectroscopy, since this technique has been used very extensively and purposefully for studies on hemes inside micellar cavities. 

The results presented in this article on the ferric and ferrous hemes in different aqueous detergent micelles have brought out several interesting features. In general, it can be observed that ironporphyrin complexes exist in monomeric form inside the micellar cavity. This is a unique advantage since it provides an opportunity to study these hemes in monomeric form in an aqueous medium without any of the usual complications of aggregation. The ferric and ferrous... 

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