Electrophoresis zonal

In the absence of K the enzyme exhibits a basal Mg -ATPase activity that can be reduced, but not completely removed, upon further purification of the enzyme by free-flow or zonal electrophoresis [66,89]. Wallmark et al. [104] demonstrated that the rate of spontaneous breakdown of phosphoenzyme corresponded very well to the Mg -ATPase activity at low ATP concentrations, implying that this activity was not due to a contaminating Mg -ATPase with a reaction path independent of the phosphoenzyme. This conclusion was confirmed by Reenstra et al. [129] in a study on the nonhyperbolic ATP dependence of ATPase activity and phosphoenzyme... 

Butler and Maxwell (1972) employed preparative zonal electrophoresis on Pevikon C870 blocks in 0.05 M barbiturate buffer, pH 8.2, to purify bovine IgM in their procedure in isolating the various immunoglobulins from whey. 

Two-dimensional (2D) electrophoretic methods are important variants of electrophoresis. In Section 6.4 we noted that electrophoresis could combine with flow in a 2D system providing continuous (and thus preparative) separation. Fundamentally, this is simply zonal electrophoresis converted into a continuous form by nonselective flow (see Section 7.5). If we observe the separation at different positions along the flow axis (as illustrated for one position in Figure 7.3), we have essentially a series of snapshots of the zones evolving with time. Each component zone is deflected from the flow axis at a unique angle as a consequence of the evolution of the electrophoretic separation. 

Most practical applications of electrophoresis in biochemistry employ some form of zonal electrophoresis, in which the aqueous ionic solution is carried in a solid support and samples are applied as spots or bands of material. Paper electrophoresis, cellulose acetate strip and cellulose nitrate strip, and gel electrophoresis are all examples of zonal... 

Figure 4-20. Schematic principles of various electrophoretic separation methods. In zonal electrophoresis (left) particles move according to their electrophoretic mobilities towards the oppositely charged electrode separation into discrete bands depends on mobility differences. In isotachophoresis (centre), the electrode and separation buffers are different. Particles in the sample form tight bands or zones, ordered according to electrophoretic mobility,...

Figure 4-21. Serum electrophoresis. Serum electrophoresis is the separation of serum proteins by simple zonal electrophoresis. It is usually carried out under slightly alkaline conditions where most of the proteins or classes of protein are negatively charged and thus migrate towards the anode.

In the simplest form of polyacrylamide gel electrophoresis (continuous zonal electrophoresis) the compositions of the electrode and gel buffers are the same separation is effected by differences in mass and charge, the latter can be altered by the choice of buffer. At pH 8-9 (for example, in diethylbarbiturate buffer) most pro-... 

Another specialised area of application of continuous zonal electrophoresis is the use of urea gradients to investigate protein stability. The gels for these studies are... 

Discontinuous zonal electrophoresis, known as disc-electrophoresis for short, is the electrophoretic technique that is most often used in protein analysis. The method, originally developed by Omstein and Davis, has given rise to several derivative techniques, notably the well-known SDS-PAGE method of Laemmli (1970). The technique is thoroughly covered in the literature, reflecting its importance in protein... 

Sucrose has been used in a few cases as a solute for zonal electrophoresis of cells (Carty et al., 1975 Gear, 1977) or for isoelectric focusing of cells (vide infra), but it is not desirable due to its osmotic effect. A mixed type isoosmotic gradient of sucrose and Metrizamide (Nyegaard, Oslo, Norway) seems more promising. 

The zeta potential of the virus at 0.02 I was measured by zonal electrophoresis in a sucrose gradient. In its evaluation we corrected the retarded, relaxed Smoluchowski equation (33) for the sucrose-dependent viscosity gradient (8). Again, the Hunter and Wright correlation was used to estimate the value of the zeta potential at 0.305 I. 

Mandel found essentially identical results as these when he determined lEPs by looking at zonal electrophoresis polarities as a function of pH in different buffers. This suggests that ampholytes used in isoelectric focusing (polyamino-polycarboxylic acids), and his buffers, had little effect on the expression of conformations. 

Capillary zonal electrophoresis has also been applied to the rapid quantitative analysis of serum retinol-RBP complex, requiring <5 min for analysis of 8... 

In another investigation (Neelin and Butler, 1961) specificity and a high degree of heterogeneity of histones were also discovered in the organs of the chicken. Histones of the spleen and liver, when tested by zonal electrophoresis on starch gel, formed 18 zones, the arrangement of which varied. Histones of the erythrocytes, however, possessed a much smaller assortment of components. 

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