Nonionic detergents tween

Since 1958 when paper electrophoresis of serum proteins was reviewed in this series (P3), there have been no major technical developments in the art. The incorporation of nonionic detergents (Tween 80, Span 20, etc.) in the conventional barbiturate buffer (D14, G18, L14) and the use of tris -borate as buffer (A14, S27) have led to the separation of 7 to 11 globulin fractions. After zone electrophoresis in borate-containing buffer, an increased number of bands can be visualized by staining, but these are not revealed by the schlieren scanning technique after free electrophoresis in similar buffers (S27) the effects of this buffer may be due to interaction between borate and proteins having a high carbohydrate content. 

FIG. 6 The displacement of bovine p-casein from the surface of a negatively charged PS latex by the nonionic detergent Tween 20, showing that protein displacement is accompanied by a decrease in the thickness of the adsorbed protein layer. (O) Protein coverage ( ) hydrodynamic layer thickness. R is the molar ratio of detergent to protein. 

Polyoxyethylene nonionic detergents (Triton X-100, Nonidet P-40, Tween-20, Brij 35, etc.) are used most often in immunochemical techniques because they generally do not denature proteins. Detergents act by intercalating into phos-... 

Surfactants are frequently used in detergents and food products to alter the properties of solution interfaces, mediating between immiscible phases because of their hydrophobic and hydrophilic moieties. The addition of surfactants increases the concentration of hydrophobic compounds in the water phase by solubilization or emulsification above a specific threshold, the critical micellar concentration (CMC), where surfactant molecules aggregate to micelles [130]. Two widely utilized nonionic surfactants, Tween 80 and Triton X-100, were evaluated in terms of enzyme interaction, by calculating the inactivation coefficient (kA) under static conditions. Concentrations lower than CMC were studied in order to avoid diffusional limitations in the interaction of the enzyme and the PAH in the micellar phase. The concentration 0.25 CMC was considered the most favorable for the enzyme, with Triton X-100 being the surfactant that led to the lowest inactivation coefficients for all the concentrations tested and was 2.5 times lower than kd in control experiment. 

Microcrystalline cellulose (Merck) appears to have been used most successfullybut even this support matrix should be used with continuous mixing to maintain adequate suspension. The inclusion of a nonionic detergent in the incubation mixture (0.5% v/v Tween-20 - 0.1% v/v Brij-35 ) helps to keep the particles dispersed and to reduce nonspecific binding. Other aproaches and matrices used with variable success have included conjugation to iron oxide particles coated with polymerized w-diaminobenzene, adsorption to individual polystyrene balls 6.4 mm in diameter, and adsorption to polystyrene plastic tubes. 

The adsorption process, unlike antigen-antibody interactions, is nonspecific. Thus, during the incubation of the immobilized antigen or antibody with enzyme-labeled antigen or antibody, the latter binds specifically to the immobilized immune reactant, but may also be adsorbed directly onto the solid phase. This nonspecific adsorption of enzyme activity can be minimized by inclusion of a nonionic detergent such as Triton X-lOO or Tween 20. These do not interfere with the antigen-antibody reaction but prevent formation of new hydrophobic interactions between added proteins and the solid phase without disrupting to any appreciable extent the hydrophobic bonds already formed between the previously adsorbed protein and the plastic surface. 

The presence of nonionic detergents, which decreases nonspecific hydro-phobic binding (e.g., Tween 20)... 

Assay Diluents As the noncovalent interactions between antibody and analyte are influenced by pH, ionic strength, and temperature, typical assay buffers are isotonic solutions at or near neutral pH. Assay buffer and diluent formulations should not only promote analyte antibody interactions but also minimize the nonspecific interactions between the critical reagents and the variety of biomolecules in the sample matrix. Components such as BSA, HSA, and nonionic detergents are often included in assay buffers. Phosphate buffered saline (PBS) or 10 mM Tris-HCl solutions (both near pH 7.4) containing 1% BSA and 0.05% Tween-20 are common buffers that can also be used for dilution of test samples and detection reagents, as well as wash buffers. When wash buffers are used in large quantities and stored at room temperature, preservatives such as sodium azide or thimerasol are often added to increase their shelf life. It should be noted, however, that some components of the wash buffer may have adverse effects... 

This is the favorite right now. It is a negatively charged medium and has a selective absorptivity for proteins and nucleic acids. It usually is treated for 5 minutes with 2% Tween 60 in a 25 mM veronal/2.5 mM citrate/1 mM oxalate buffer at pH 8.6 before use. Pore sizes are 0.3 to 0.5 pm, with 0.45 pm being usual. Its capacity for proteins is 80 to 100 pg/cm. It appears to bind proteins by a hydrophobic interaction. Nonionic detergents can remove large amounts of bound protein. 

Nonionic detergents - weaker groups for hydrogen bonds, apolar groups and are able to solubilize membranes examples are, Triton X-100, and Tween 20. 

In 1951 Kellner et al. reported that administration of the nonionic detergents Triton A-20 or Tween 80 to rabbits and guinea pigs was followed by a sustained hyperlipemia. This observation was later extended to other animal species mice (Hirsch and Kellner, 1956a, b), rats (Friedman and Byers, 1953), and dogs (Scanu et al., 1961). Studies by Friedman and Byers (1953, 1957) and Hirsch and Kellner (1956a, b) led to the hypothesis that the hyperlipemia was secondary to the action of the detergent on the physical and chemical properties of plasma lipoproteins. Experimental support for this hypothesis was provided by the... 

Minard (312) showed that some nonionic detergents—the Tweens, fatty acid esters of polyoxyethylene sorbitan— inhibited hydrolysis by pancreatic lipase of com oil, and that this inhibition could be reversed... 

Detergents 0.1-2.0%, Triton X-100, Tween 20 Avoid inactivation of enzyme reagents Nonionic detergents are preferable Low concentrations of anionic detergents may be used with adequate washing... 

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