Pore gradient electrophoresis

Rodbard, D Kapadia, G Chrambach, A, Pore Gradient Electrophoresis, Analytical Biochemistry 40, 135, 1971. 

Rothe, GM, Determination of Molecular Mass, Stoke radius. Frictional Coefficient and Isomer-Type of Non-denatured Proteins by Time-Dependent Pore Gradient Gel Electrophoresis, Electrophoresis 9, 307, 1988. 

To put the preceding analysis into a more applied framework, let us consider the peak broadening in pore gradient electrophoresis (5, 6, 9). For this problem, let D and D0 represent the diffusion coefficient in the gel and in the absence of a gel, and M and M0 the respective mobilities. For many gels these variables experimentally satisfy Equation 5 ... 

Figure 1. A comparison of the exact and approximate concentration profiles (0 = c/c0) (Equations 13 and 18) for pore gradient electrophoresis, fore = 5 X 10 3, r = 5...

D. Rodbard, G. Kapadia, and A. Chrambach, Anal. Biochem., 40 135-157 (1971). Pore Gradient Electrophoresis. 

The subunit structure of the three enzymes was studied by SDS pore gradient electrophoresis. VI and V2 each comprise two subunits of 19 and 20 kilodaltons each, and V3 comprises a single 20 kilodalton polypeptide chain (see Figure 2). 

For the second dimension, a laboratory- or readymade SDS pore gradient gel (0.5 mm thick on GelBond PAGfilm) is placed on the cooling block of the horizontal electrophoresis unit. Electrode wicks (Bio-Rad) or buffer strips from acrylamide are then applied. The equilibrated IPG gel strip is simply placed gel side down onto the surface of the horizontal SDS gel without any embedding procedure. Horizontal setups are perfectly suited for the use of readymade gels on film supports. 

Figures. Typical plots of log M, against migration distance D or gel composition yrT afler pore gradient electrophoresis Note that these plots are nonlinear, whereas when log M,. is plotted against /D or s/Wf a linear relation.ship is obtained 77).

Figure 3.27 Polyacrylamide gradient gel electrophoresis of human serum proteins. The proteins are separated in a gel which has an increasing concentration gradient with a parallel decrease in pore size, which restricts the movement of the larger molecules. Note the large number of different protein bands that can be demonstrated. (Photograph by permission of Dr D. Brocklehurst, Department of Clinical Chemistry, Doncaster Royal Infirmary, UK.)...

CZE is a high resolution method provided that the sample is concentrated (>1 mg/ml) so that it can be loaded in a narrow zone. The buffer and pH for separation can be freely chosen, but buffer concentration should not exceed O.OIM to minimize Joule heating. In a homogeneous gel, separation occurs on the basis of both charge and size. In contrast, in a gradient polyacrylamide gel migration rates decrease until each protein species reaches its pore limit (15-17). This technique is termed "pore limit electrophoresis" and separates proteins on the basis of size. 

Electrophoresis Electrophoresis (also known as cataphoresis) is the transport of charged particles of colloidal size and bound contaminants due to the application of a low DC or voltage gradient relative to the stationary pore fluid. Compared with ionic migration and electroosmosis, mass transport by electrophoresis is negligible in low-permeabihty soil systems. However, mass transport by electrophoresis may become signiflcant in soil suspension systems, and it may also be a dominant transport mechanism for biocoUoids (i.e. bacteria) and micelles. 

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