Sodium dodecyl sulphate solubilization

The solubility of proteins from parasitic organisms can often be enhanced by the use of hot sodium dodecyl sulphate (SDS) before solubilization in SD buffers. The ability of SDS to denature proteins also helps in allowing access to hydrophobic proteins, not normally seen after standard preparation procedures. SDS treatment in whole F. hepatica preparations has been shown to yield more protein spots visualized on gel analysis than other methods (Jefferies et a/., 2000). 

An excess amount of surfactant can solubilize proteins, presumably by additional adsorption to the surface and generation of a large net charge at the surface of the protein molecule. This is the basis for estimation of protein molecular weight by gel electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE). Such effects are usually found only at surfactant concentrations well in excess of those normally found in foods, and have more use in laboratory investigations than in ordinary applications. 

The major components of beef glomerular basement membrane were solubilized with sodium dodecyl sulphate and resolved on 6% agarose [229]. 0.1% SDS has also been used in the separation of lipoprotein and apolipoprotein from human plasma [230] and 3% SDS used in gel chromatography of human erythrocyte membranes on Sepharose 6B [231]. Stokes radius determination of insulin-binding protein was performed on Sepharose 6B with 0.5% Triton X-100 [232]. 

A membrane-derived a-amylase was solubilized from membrane vesicles by treatment with Triton X-100 and was highly purified by chromatography on an anti-a-amylase-protein A-Sepharose column. Membrane-derived a-amylase was indistinguishable from the soluble extracellular enzyme by sodium dodecyl sulphate-gel electrophoresis and radioimmunoassay. The membrane-derived enzyme contains phospholipid. Approximately 30 to 80% of the phospholipid was extracted from the purified enzyme by chloroform-methanol. The extracted phospholipid was predominantly phosphatidylethanolamine. Treatment with phospholipase D released phosphatidic acid. Membrane-bound a-amylase was latent in membrane vesicles. Release of membrane-bound a-amylase from vesicles by an endogenous enzyme was maximal at pH 8.5, was inhibited by metal chelators and di-isopropyl fluorophosphate and was stimulated by Ca and Mg. The amount of membrane-bound a-amylase was related to the level of secretion. 

It is known that [Ru(bipy)3] + forms a water-insoluble salt with dodecyl sulphate ions which is solubilized by sodium dodecyl sulphate micelles. Kinetic measurements reveal that all the [Ru(bipy)3] + are bound to micelles and reside in a negatively charged ionic atmosphere. As a consequence the reaction of [Ru(bipy)3] + with eaq is retarded and those of Zn+, Cd+, and Co+ are accelerated. The micellar environment also has a dramatic effect on the quenching of... 

Protoferrihaem IX intercalated in sodium dodecyl sulphate (SDS) micelles has been studied as a model system for cytoehrome c. Hydrated electrons reduce the solubilized haemin with k = 5.2x 10 s at pH 9.2, and MeCHOH... 

A review by Maier and Soberon-Chavez [ 19] showed that hexadecane, tetradecane, pristine, creosote and hydrocarbon mixture in soils. Other researchers [35] compared the solubilization of naphthalene by a rhamnolipid, sodium dodecyl sulphate (SDS), an anionic surfactant and Triton X-100, a non-ionic surfactant. The biosurfactant increased the solubility of naphthalene by 30 times. However, biodegradation of naphthalene (30mg/L) took 40 days in the presence of biosurfactant (lOg/L) compared with lOOh for an equal concentration of Triton X-100 (10 g/L). It appeared that the biosurfactant was used as a carbon source instead of the naphthalene which did... 

Because of this dual character of its molecules association colloids are of great practical utility. Most of them are surface-active substances. Examples of this class are the soaps and detergents like sodium dodecyl sulphate. While some are excellent solubilizers of various types of organic compounds in water, others are good dispersion stabilizers. 

Evidence supporting hydrogen bonding between cyanide ions bound to ferric porphyrins and the solvent has been obtained (see, e.g., refs. 176 and 177), and the effects of aqueous and reversed micelles on the interaction of surfactant-solubilized monomeric haemin with imidazole in water, cyclohexane, and benzene have been reported. The reduction of haemin (Hm) by dithionite has been studied in sodium dodecyl sulphate micelles (added to render the haemin monodisperse) and the following scheme proposed ... 

An act-trehalase solubilized with Triton X-100 and butanol from microvillous membranes of the intestinal mucosa of rats has been purified by gel filtration and ion-exchange chromatography to yield a fraction (mol. wt. 9.6 x 10 in the presence of sodium dodecyl sulphate) that was homogeneous on polyacrylamide gel electrophoresis. The enzyme (pH optimum 5.5—5.7), which shows a high specificity for aa-trehalose K 5.4 mmol 1 ), was inhibited by 4-chloromercuri-benzoate, mercuric chloride, and tris(hydroxymethyl)aminomethane. 

The Cotton effect of the probe when incorporated in micelles of both hexadecyltrimethylammonium bromide and sodium dodecyl sulphate more closely resembles that of water than heptane, suggesting an aqueous environment for the solubilized probe. 

In simple sphingomyelin-Triton X100 systems, the sphingomyelin is dispersed as bilayers below a surfactant concentration of 0.2 mM. Above this concentration mixed micelles formed [301, 302]. Studies of the transfer of cholesterol solubilized in sodium dodecyl sulphate to PC liposomes has shown that 90 % of... 

The simultaneous solubilization of some steroids in aqueous polysorbate 40, tetradecyltrimethylammonium bromide and sodium dodecyl sulphate has been studied [182,183]. The results are discussed in detail in Chapter 6 and in general support the view that in systems where the solubilizates are located in different sites, they are solubilized independently of each other. For example, the... 

The membranes were obtained and purified by standard procedures. They were resuspended in 0.25 M-sucrose/lOmM-Tris/HCl buffer, pH 7.4, to a concentration of 1 mg protein. Detergents were then added to obtain final concentrations between 0.1 and 1.0% (w/v), and the suspensions were incubated at 20° C for 30 min. Each preparation was centrifuged for 1 h at 1 SOOOOgav., at 4° C (Triton X-100 and deoxycholate treatments) or 18° C (sodium dodecyl sulphate). The supernatant was assumed to contain the solubilized fraction of the membranes. 

The polypeptides of the light-harvesting complex are most easily resolved by polyacrylamide gel electrophoresis of thylakoid membranes solubilized with sodium or lithium dodecyl sulphate. This produces the green chlorophyll-protein band, CP II, which on staining for protein reveals up to four polypeptides of 24-27 kDa [2], each of which is believed to bind Chi a and Chi b. In most plants two polypeptides predominate, but other minor polypeptides may be resolved [2]. 

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