Solubilization problems associated with

There are several problems associated with immunoblotting. The antigen is solubilized and electrophoresed in the presence of denaturing agents (e.g., SDS or urea), and some antibodies may not recognize the denatured form of the antigen transferred to the membrane. The results observed may be entirely dependent on the denaturation and transfer system used. For... 

Cytochrome oxidase also serves as a proton pump, so that the process of electron transfer is associated with the vectorial transfer of protons across the membrane, and thus contributes to the establishment of the proton gradient which is used to drive the synthesis of ATP. Cytochrome oxidase is located in the inner mitochondrial membrane of animal, plant and yeast cells (the eukaryotes) and in the cell membrane of prokaryotes. The arrangement is represented schematically in Figure 58. The complexity of cytochrome oxidase and the problems associated with its solubilization from the membrane have presented great obstacles to the elucidation of the structure and mechanism of the enzyme, but its importance has resulted in an enormous literature, which has been reviewed frequently.1296 1299... 

Micelles are molecular aggregates formed in solutions of surface-active agents (surfactants compounds that orient at an interface such as between oil and water) (McAulifFe, 1980). Micelles may contain up to 100 or more surfactant molecules with a nonpolar (hydrophobic) end on the inside and a polar (hydrophilic) end on the outside. In 1959, Baker first advanced the concept of solubilization of hydrocarbons in (soap) micelles as a possible primary migration mechanism. The possible role of soaps, i.e. salts of organic acids, in primary migration was supported by Cordell (1973). The concept was considered attractive because it also explains how the practically water-insoluble hydrocarbons can solubilize in groundwater at relatively low temperatures. However, the likelihood of micellar solution as an effective primary migration mechanism has been seriously questioned by many authors (for instance Price, 1976 Hunt, 1979 Tissot and Welte, 1984). The main problems associated with micellar solution are ... 

Paraphernalia associated with the use of heroin may also be encountered. These items include metal spoons, materials used in the process of dissolution and heating heroin (candles, foil, etc.), materials used to filter the dissolved samples, such as cotton wool, and items used for the injection of the solubilized product. All such materials should be treated with care due to the problems associated with needle-borne diseases. 

The formation of inclusion bodies reflects a general and often intractable problem associated with expression of eukaryotic DNA s in prokaryotes. Even though significant amounts of insoluble protein can be isolated, solubilization by denaturation and refolding often results in low recoveries, particularly when refolding is attempted... 

An important number of organic reactions are now catalyzed by whole cells or isolated enzymes. However, there are still problems associated with the solubility, yield and selectivity of these biotransformations. Ever since the solubilization of alkaline phosphatase in a mixture of [Et3NH][N03] and water (4 1), it has been known that enzymes can be stable in ionic liquids. Recent research shows that ionic liquids can be used efficiently as a medium for biocatalytic processes. ... 

Initially polymers were used as solubilizers, stabilizers, and mechanical supports for sustained release of drugs. However, over a period of time, the functionalities of polymers have changed. The polymers have been synthesized and designed to suit specific needs or rather solve specific problems associated with development of drug delivery systems. 

Similar to the other rigid aromatic polymers, the insolubility of polyphenylenes constitutes the major problem associated with their synthesis and characterization [5] indeed, this is the very reason why most polyphenylenes synthesized to date have been decorated with solubilizing side chains. Such substituents not only cause the dihedral angles to be detrimental for conjugation when connected at ortho positions (see Section 22.5.1), but they also dilute the main-chain properties, particularly in bulk. Consequently, the aim has been to reduce the side chain content as much as possible for certain applications. Bearing this in mind, Schliiter and coworkers have synthesized a variety of alkyl chain-substituted PPPs with systematically decreased densities of the side chains (Figure 22.22) [34]. 

There are a number of technical problems associated with biochemical studies on RARs. These include the fact that these proteins are not abundant in most cells and tissues, that high-specific activity retinoids will be required to detect binding and that high concentrations of salt are required for the solubilization of these proteins from nuclei and this may interfere with certain types of experiment. Higher levels of RAR expression may be obtained by transfection of cells with RAR cDNAs. RARs have been successfully extracted from transfected cells, although the subcellular localization may be different to that generally observed in normal cell lines (7). 

In vitro enzymatic polymerizations have the potential for processes that are more regio-selective and stereoselective, proceed under more moderate conditions, and are more benign toward the environment than the traditional chemical processes. However, little of this potential has been realized. A major problem is that the reaction rates are slow compared to non-enzymatic processes. Enzymatic polymerizations are limited to moderate temperatures (often no higher than 50-75°C) because enzymes are denaturated and deactivated at higher temperatures. Also, the effective concentrations of enzymes in many systems are low because the enzymes are not soluble. Research efforts to address these factors include enzyme immobilization to increase enzyme stability and activity, solubilization of enzymes by association with a surfactant or covalent bonding with an appropriate compound, and genetic engineering of enzymes to tailor their catalytic activity to specific applications. 

For some foods, incomplete extraction of color is obtained, probably due to the high binding affinity of dyes to the bulk of the food matrix, especially to proteins, lipids, and carbohydrates (156,161,162). This problem can be overcome by the use of selected solvents or enzymes to digest the food prior to extraction. Petroleum ether can be used to extract lipids (163). Acetone can be used to remove lipids and coagulate protein (164). Enzymes, such as amyloglucosidase (165,166), papain (167), lipase, pectinase, cellulase, and phospholipase, added to the sample and incubated under optimum pH and temperature conditions release synthetic colors bound to or associated with the food matrix. Furthermore, enzyme digestion can solubilize some foods, enabling analysis to be continued (156). 

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