Electrophoretic zones

Many 2D planar structures have been used to implement deflection (continuous flow) electrophoresis. The primary requirement is that flow and electrophoresis be carried out simultaneously and uniformly. Hanging paper curtains soaked with electrolyte and fed a stream of electrolyte from above served admirably for this purpose when the technique was initiated in the 1950s. In recent years thin flow channels enclosed between flat plates have become important. The process is complicated by parabolic flow, which distorts and effectively broadens the electrophoretic zones. More detail is available in the cited references on electrophoresis [3-5]. 

J. R. Cann, Biochemistry, 5 1108-1112 (1966). Multiple Electrophoretic Zones Arising from Protein-Buffer Interaction. 

Buffer ions have a twofold purpose in electrophoresis they carry the applied current, and they fbc the pH at which electrophoresis is carried out. Thus they determine the kind of electrical charge on the solute, the extent of ionization of the solute, and therefore the electrode toward which the solute will migrate. The buffer s ionic strength determines the thickness of the ionic cloud (buffer and nonbuffer ions) surrounding a charged molecule, the rate of its migration, and the sharpness of the electrophoretic zones. With increasing concentration of ions, the ionic cloud increases in size, and the molecule becomes more hindered in its movement. For the separation of serum proteins, the barbital or tris-boric acid-EDTA buffers remain the most popular. 

A single polypeptide chain can in theory exist in an infinite number of different conformations. However, one specific conformation generally appears to be the most stable for any given sequence of amino acids, and this conformation is assumed by the chain as it is synthesized within the cell. Thus, the primary structure of the polypeptide chain also determines its three-dimensional secondary and tertiary structures. It is conceivable that in some cases there may be several alternative conformations ("conforraers ) of a single chain that are of nearly equal stabilities and therefore these alternative forms may coexist. This possibility was first suggested to account for the heterogeneity noted in preparations of the cytoplasmic and mitochondrial isoenzymes of malate dehydrogenase and has also been proposed as an explanation of the multiple electrophoretic zones of erythrocyte acid phosphatase. However, no multiple enzyme forms have been shown unequivocally to be due to conformational isomerism. 

The behaviour of radionuclides i s olljOwed up by measuring their electrophoretic mobility (u) (cm V s ) (S ) and by evaluating the amount of the respective radionuclide in the three observable zones, i.e. cationic, anionic, and the immobile zone at the starting point. The electrophoretic zones could be detected conveniently by autoradiography exposing an X-ray film overnight to the electrophoretic strips. The respective zones were cut from the paper and counted in a 3-llquid scintillation counter or in ay-counter. 

In Figure 5 we have tried to demonstrate the Influence of both the concentration of fulvic acid and of the aging of the system on the distribution of electrophoretic zones of Fe in diluted seawater. The concentration of 10 mg of FAC in 10% seawater produces a tremendous increase lnj.the cationic zone/tailing of Fe, amounting to 80.7% of the total Fe present (without FAC only 1.2% of Fe is in the cationic tailing zone). However, after aging 27 days, this zone dropped to only 0.4% in favour of the anionic zone (48.4%). At FAC concentrations of 100 mg dm the anionic Fe zone amounted to 9%, and after 27 days it amounted to 79.6% of the total Fe. 

Table VI. Distribution of electrophoretic zones of Fe in 10% seawater-humic acid (HAM) systems (%)...

Mn zones showed the spread of the radioactivity from the cationic to the anionic values without any electrophoretic zone defined. In other words, at the intermediate EDTA concentrations, which were not high enough to complex all manganese present, both Mn-EDTA complexes and free Mn were present at each position of the electrophoretic rip moving in opposite directions and resulting in the spread of... 

Figure 9.3 depicts the concept of ECEEM schematically. In contrast to NECEEM, in ECEEM the capillary is filled with T at a concentration identical to that in the equilibrium mixture. Therefore, quasiequilibrium will be maintained during electrophoresis if the time reqnired for reeqnilibration is shorter than the characteristic time of separation. In snch a case, the equilibrium mixture will be migrating as a single electrophoretic zone with an effective velocity being a function of fifd and [T], If Kd [T], most of L will be free and the... 

Yefimov, S. Yergey, A. L. Chrambach, A. Transfer of SDS-proteins from gel electrophoretic zones into... 

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