Crossing over electrophoresi

A number of developments to further improve the resolution and specificity of the method have been reported [78,79], namely cross-over electrophoresis, rocket electrophoresis, two-dimensional Immunoelectrophoresis, and radioimmunoassay. 

There are many proteins in the human body. A few hundreds of these compounds can be identified in urine. The qualitative determination of one or a series of proteins is performed by one of the electrophoresis techniques. Capillary electrophoresis can be automated and thus more quantified (Oda et al. 1997). Newer techniques also enable quantitative determination of proteins by gel electrophoresis (Wiedeman and Umbreit 1999). For quantitative determinations, the former method of decomposition into the constituent amino acids was followed by an automated spectropho-tometric measurement of the ninhydrin-amino add complex. Currently, a number of methods are available, induding spectrophotometry (Doumas and Peters 1997) and, most frequently, ELISAs. Small proteins can be detected by techniques such as electrophoresis, isoelectric focusing, and chromatography (Waller et al. 1989). These methods have the advantage of low detection limits. Sometimes, these methods have a lack of specifidty (cross-over reactions) and HPLC techniques are increasingly used to assess different proteins. The state-of-the-art of protein determination was mentioned by Walker (1996). 

Polyacrylamide shows many advantages over starch gel as a medium for high resolution electrophoresis and because of its synthetic nature its pore size can be more easily controlled. The gel is formed by the polymerization of the two monomers, acrylamide and a cross-linking agent, N, iV-methylene-bis-acrylamide (Figure 3.26). The proportion of the two monomers and not their total concentration is the major factor in determining the pore size, the latter having more effect on the elasticity and... 

As in the case of the cisplatin interstrand cross-links, several techniques have been used to characterize the distortions induced in the DNA double helix by the transplatin interstrand cross-links. From gel electrophoresis [68] it has been deduced that the DNA double helix is unwound (12°) and its axis is bent (26°) toward the major groove. Chemical probes and DNase I footprinting indicate that the distortion of the double helix spreads over four-... 

Figure 1.3. Thin fused silica capillary tubes similar to (and frequently smaller than) those shown here are often used for the analytical-scale separation of complex mixtures by chromatography and electrophoresis. The inside diameters of these capillaries are only 220 /im (lower two) and 460 fim (upper). The diameters of the smaller tubes are 680 times less than that of the LC column shown in Figure 1.2. The cross-sectional area, roughly proportional to separative capacity, is over 400,000 times less. (Photo by Alexis Kelner.)...

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