Membrane protein extract applications

One area of rapidly expanding interest is the use of reverse micellar systems of sugar-based surfactants in the extraction of proteins and other sensitive materials. The use of hydrophilic, nonionic, sugar-based surfactants for membrane protein extraction is well known to be effective due to the mild, nondenaturing properties of these surfactants when compared with ionic surfactants or polyoxyethylene derivatives. For the same reasons, protein extraction into reverse micellar systems is now becoming a popular medium for such applications. Alkyl sorbitan esters and ethoxylated sorbitan esters, such as Tween 85 [107] and Span 60 [108], have been used successfully to form reverse micellar systems for protein extraction. Blends of Tween and Span have also been found to be effective for this purpose [109]. More recently, commercially available sucrose fatty acid esters have been shown to form biocompatible reverse micellar systems into which cytochrome c is effectively extracted [110]. 

Membrane contactor offers potential solution in a wide range of gas/liquid and liquid/liquid applications gas adsorption and stripping, liquid/liquid extraction, dense gas extraction, fermentation and enzymatic transformation, pharmaceutical applications, protein extraction, wastewater treatment, chiral separations, semiconductor manufacturing, carbonation of beverages, metal ion extraction, protein extraction, and VOCs removal from waste gas [55]. 

Membrane proteins can thus be separated (and visualized) following disruption of protein interactions with other protein or lipid membrane components, by gel electrophoresis. One useful method is the layering of an SDS extract solution onto a polyacrylamide gel followed by application of an electrical field. The resulting differences in electrophoretic mobility then separates the individual proteins based on their mass (not charge). This is called SDS-polyacrylamide-gel electrophoresis (SDS-PAGE). 

Future studies in this area will require the radiolabelling of intrinsic membrane so that the amount of protein entering the monolayer can be accurately measured. More information should also be obtained on the dependence of the initial monolayer surface pressure on protein mediated fusion of vesicles with monolayers. The surface pressure at which the properties of a monolayer most closely mimic the properties of a bilayer is known to be relatively high. It is clear from our studies that protein extracts penetrate monolayers upto equilibrium surface pressures approaching the monolayer collapse pressure which suggests that data can be obtained from monolayer studies at surface pressures which are directly applicable to bilayers. 

Perfect extraction of intrinsic membrane proteins or enzymes from intact cells and reconstitution of them without any denaturation and deactivation are basic requirement in investigation of the function of membrane proteins and/or the utilization of them in membrane protein engineering. For this purpose, artificial cell, liposome, seems to be a desirable and promising tool in both basic investigation and application. 

On-Tissue Digestion Method Traditional MALDI is used to generate intact molecular ions of proteins up to m/z 100,000. In the current IMS technology, however, the upper mass limit of protein detection is approximately 40 kDa because the detection sensitivity severely falls at higher mass [15]. This is a considerable limitation which narrows the application capability of this technology. As another important problem, insoluble proteins to the matrix solution, such as membrane proteins, which is a protein molecule that is attached to the membranes, are difficult to be extracted into the applied matrix solutions and thus hardly crystallize with matrix, and they were in turn difficult to detect. On this... 

Membrane bioreactors have applications in fermentation, pharmaceutical production, protein extraction and wastewater treatment (Inloes et al., 1983 Gabelman and Hwang, 1999). Membranes can be used in the recycle loop with other types of reactor, such as CSTR, in which the membrane module is used to separate the cells from the product stream and then recycle the cells back into the reactor. In another arrangement, cells or enzymes can be entrapped on the surface of the membrane or incorporated into the membrane s porous structure. The substrate is fed through the lumen and product leaves the other side of the lumen through the shell side of the module. 

The biological applications of NMR include the study of the structure of macromolecules such as proteins and nucleic acids and the study of membranes, and enzymic reactions. Newer methods and instruments have overcome, to a large extent, the technical difficulties encountered with aqueous samples and the analysis of body fluids is possible, permitting the determination of both the content and concentration of many metabolites in urine and plasma. NMR is not a very sensitive technique and it is often necessary to concentrate the sample either by freeze drying and dissolving in a smaller volume cm- by solid phase extraction methods. 

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