Size exclusion dialysis

After application of the enzyme a membrane (size exclusion dialysis membrane) is put over the electrode surface and prevents the diffusion of the protein and/or other components into the test solution. This way seems the simplest method for immobilization of enzymes and has been frequently employed.Nevertheless, any membrane at the surface hinders the mass transport of the analyte to some extent resulting in decreased signals and longer response times. 

Purify the modified protein away from reactants and reaction by-products using dialysis or size exclusion chromatography. 

Purify the biotinylated dendrimer by diluting it with an equal volume of water and then using dialysis, ultrafiltration, or size exclusion chromatography. 

Purify the DTPA-dendrimer using dialysis, size exclusion chromatography, or spin-tube concentrators having a molecular weight cutoff of 5,000 Daltons. 

Remove excess crosslinker and reaction by-products by dialysis or size exclusion chromatography. For small quantities of bait proteins, dialysis may be the better choice, because gel filtration columns often bind nonspecifically enough protein to make recoveries unacceptably low. 

The micropipette tip containing solid phases is a relatively new sample preparation technique that permits handling of microliter to submicroliter amounts of liquid samples, using the techniques of SPE, dialysis, and enzyme digestion. Various phases (reversed-phase, affinity, size-exclusion, etc.) are packed, embedded, or coated on the walls of pipette, permitting liquid samples to be transferred without undue pressure drop or plugging (Fig. 2.5). 

Vinyl alcohol copolymer gel is hydrophilic and has been developed for aqueous-phase size-exclusion liquid chromatography however, it is less polar than the polysaccharides. Its specificity permits the direct injection of a biological sample without deproteinization. For example, blood serum from a patient suffering from chronic nephritis has been injected directly as a measure of the degree of dialysis (Figure 3.17). Adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate in red blood cells have also been separated directly (Figure 3.18). Theophylline in blood serum has been... 

EROD activity is measured in the H411E cells as follows. The cells are seeded at 7,000 cells per well in 250 xL of Dulbecco s modified Eagles culture media (Tillitt et al., 1991). After an initial incubation period of 24 hours, the cells are dosed with 5 xL volumes of eiuiched SPMD extracts (cleanup of extracts generally includes dialysis and size exclusion chromatography [SEC]) and incubated for an additional 72 hours. Sample dose is typically expressed as g-equivalents triolein or whole SPMD per mg cellular protein. Multiple exposures are performed at each of six (typically) sample concentrations, using a dilution series. Afterwards, the microtiter plates are washed three times with distilled water to lyse the cells. EROD activity (pmol mg cellular protein per min) in each sample is measured... 

Several variants of separation methods based on dialysis, ultrafiltration, and size exclusion chromatography have been developed that work under equilibrium conditions. Size exclusion chromatography especially has become the method of choice for binding measurements. The Hummel-Dreyer method, the vacancy peak method, and frontal analysis are variants that also apply to capillary electrophoresis. In comparison to chromatographic methods, capillary electrophoresis is faster, needs only minimal amounts of substances, and contains no stationary phase that may absorb parts of the equilibrium mixture or must be pre-equilibrated. 

It is essential that the procedure described in Section 3.1.2. be performed approx 24 h before the procedure described in Section 3.1 3, because the deprotected thiolated avidin and the maleimide derivative of the protein are unstable. Purification of the maleimide-derivatized protein by size exclusion chromatography can be performed more rapidly than dialysis, however, the former leads to dilution of the protein and a decrease in the yield of the conjugate. 

Remove salt while exchanging the reaction mixture with an appropriate buffer system by dialysis or size-exclusion chromatography. 

The authors have applied this same procedure to peach purees, although at the pH of the peach product (—3.9). In that case, however, the PGase activity associated with the peach puree was relatively soluble in water. Hence, the initial water extracts had significant PGase activity. Therefore, one may choose to assay the water extract itself. As noted in the protocol for removal of salt, the soluble reducing sugars in the water extract can be removed by techniques such as dialysis or size-exclusion chromatography. 

In this strategy, it is very important to avoid interphage catalysis. Therefore, the phage concentration should be kept low (lower than 10-9 M) and phages should not be precipitated with PEG. Because removal of excess label is generally required before affinity capture, it should be done by phage dialysis or size-exclusion chromatography. 

SPMD Triolein Nonporous LDPE membrane Hydrophobic organic compounds Integrative 1 month Dialysis in organic solvents, size exclusion chromatography 29... 

Nanoparticles can be purified by repeated centrifugation, by size exclusion chromatography, by dialysis or using Soxhlet extraction.147... 

Desalting Size-exclusion (gel-permeation) Electrodialysis Dialysis Higher throughput for given size of equipment... 

A number of experimental methods are used to determine the amount of bound drug and/or free drug in a mixture, including equilibrium dialysis, steady-state dialysis, ultrafiltration, and size exclusion chromatography. Each of the methods is described briefly here. 

From the great variety of methods for the determination of protein binding three separation methods, equilibrium dialysis (ED), ultrafiltration (UF), and ultracentrifugation (UC) and a non-conventional method with the binding to immobilized proteins has been chosen. The first methods are undoubtedly the most widely used because of their simplicity and general applicability to many different systems. Other methods e.g. size exclusion chromatography, capillary electrophoresis, or spectroscopic methods have been not described. Oravcova et al. (1996) gives a comprehensive review and comparison for these applications. 

Removal of unwanted high-molecular-weight substances by size exclusion chromatography, dialysis, ultrafiltration, precipitation, and use of supported liquid membrane. 

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