Isoelectric focusing characterization

Santora, L. C., Krull, I. S., and Grant, K., Characterization of recombinant human monoclonal tissue necrosis factor-alpha antibody using cation-ex-change HPLC and capillary isoelectric focusing, Anal. Biochem., 275, 98,1999. 

Another limitation of 2D gels is that membrane proteins are underrepresented. Because membrane proteins account for approximately 30% of total proteins (Wallin and Von Heijne, 1998), this is a serious problem for characterization of the proteome. The relative lack of membrane proteins resolvable on 2D gels can be attributed to thee main factors (i) they are not abundant, and therefore are difficult to detect by standard staining techniques, (ii) they often possess alkaline pi values, which make them difficult to resolve on the pH gradients most often used for isolelectric focusing, and (iii) the most important reason for under representation may be that membrane proteins are poorly soluble in the aqueous media used for isoelectric focusing (Santoni et al., 2000). Membrane proteins are designed to be soluble in lipid bilayers and are therefore difficult to solubilize in water-based solutions. 

Isoelectric focusing, as previously discussed, has been used to isolate and characterize the milk proteins (Josephson et al. 1971 Kaplan and Foster 1971 Peterson 1971 Josephson 1972 Josephson et al. 1972). Greater heterogeneity was observed in the caseins than was noted in... 

Polyacrylamide gel electrophoresis is one of the most commonly used electrophoretic methods. Analytical uses of this technique center around protein characterization, for example, purity, size, or molecular weight, and composition of a protein. Polyacrylamide gels can be used in both reduced and nonrcduced systems as well as in combination with discontinuous and isoelectric focusing (ief) systems. 

Electrophoresis plays a key role as an analytical or preparative technique in the characterization of natural organic matter because it gives information about the behavior of these molecular mixtures in controlled solution conditions, depending on both the size and the charge distribution frequency of the analytes in the complex mixture. Historically, the first electrophoretic separations were conducted with environmental colloids and over the years all the techniques based on zone, gel electrophoresis, or isoelectric focusing were used in their different setups to analyze natural organic matter and environmental particles to a minor extent. The goal of... 

Garcia, C., Hernandez, T., and Ceccanti, B. (1995). Characterization by isoelectric focusing of the organic matter of a regenerated soil. Commun. Soil Sci. Plant Anal. 26, 3033-3041. 

Govi, M., Bonoretti, G., Ciavata, C., and Sequi, P. (1994). Characterization of soil organic matter using isoelectric focusing a comparison of six commercial carrier ampholytes. Soil Sci. 157, 91-96. 

Schmitt, R, Garrison, A.W., Freitag, D., and Kettrup, A. (1997a). Capillary isoelectric focusing (CIEF) for the characterization of humic substances. Water Res. 31, 2037-2049. 

Dixon, B. R. Arai, H. P. (1985). Isoelectric focusing of soluble proteins in the characterization of three species of Hymenolepis (Cestoda). Canadian Journal of Zoology, 63 1720-3. 

Biochemical characterization of Australian strains of Echinococcus granulosus by isoelectric focusing of soluble proteins. International Journal for Parasitology, 14 581-6. 

Chemiluminescence detection in capillary electrophoresis (CE) has attracted much attention as a promising way to offer excellent analytical selectivity and sensitivity. Several reagents, such as luminol, acridinium, peroxyoxalate, and tris(2,29-bipyridine)ruthenium(II) complex have been utilized. Since chemiluminescence detection is approximately 102—106 times more sensitive than spectrophotometric and fluorometric detections, its combination with isoelectric focusing may result in a highly sensitive analytical tool for amphoteric compounds, e.g., proteins and peptides. A detector using luminol-H202 chemiluminescence has been characterized in a very simple and inexpensive setup, but only pressure-driven mobilization of the zones was effective. [68],... 

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