Filter paper electrophoresis

Simon, N., Radioactive gold in filter paper electrophoresis patterns of plasma. Science 119, 95 (1954). 

An octapeptide, Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala, which has a delicious taste, was isolated from beef treated with papain by the use of gel filtration and ion-exchange chromatography, and filter paper electrophoresis (33) A sensory evaluation showed that this octapeptide produced synthetically also elicited a delicious taste (54) The elimination of two amino acid residues at N-terminus, Lys-Gly, led to the disappearance of the savory taste and changed it into a sour taste. This indicated that the residues, Lys-Gly are important to the savory taste. 

The behavior of heparin in filter-paper electrophoresis has also been studied. ... 

As in all electrophoretic procedures, a rigidly standardized technique is essential for consistent results. However, the variable absorption of the proteins in paper, and their different protein dye-binding capacities used for quantitation (see Section 6.5), necessitate several corrections which are both tedious and impractical. Such corrections are frequently ignored on the ground of simplicity. In the opinion of the writer, filter paper electrophoresis of serum albumin and globulins is an inaccurate separative procedure which is now outmoded. 

LI. Larson, P., Deiss, W. P., and Albright, E. C., Localization of protein-bound radioactive iodine by filter paper electrophoresis. Science 116, 626 (1952). 

Smith, E. W., and Conley, C. L. 1953. Filter paper electrophoresis of human hemoglobins with special reference to the incidence and clinical significance of hemoglobin C. Bull. Johns Hopkins Hosp. 93, 94. 

One of the chief disadvantages of filter paper electrophoresis of all types is the difficulty in reproducing the exact same pattern from one experiment to another (65). There are so many variables in the filter paper itself, in the preparation of the paper for the separation, in the buffer concentration, in the electrical system, in the temperature, and in the staining that small deviations are almost impossible to control. To circumvent these difficulties it is advantageous to carry out a number of separations on the same sheet of paper under identical conditions (65). In this way one specimen can always serve as a control and the unknowns can be expressed quantitatively in relation to the control. Considerable effort has been directed to the problem of obtaining exactly similar migrations and separations of 10 to 14 specimens of the same serum on one sheet of paper. The provision of even distribution of pressure over the glass plates was of prime... 

Despite the relatively large number of papers that have appeared on filter paper electrophoresis, the amount of new information obtained with this procedure has been fairly small. The reason for this is that most people have applied the procedure to serum for clinical purposes, and analyses by free electrophoresis in this field have been carried out in the past in a far more quantitative manner. The method has proved more useful for other biological fluids, where it is difficult to obtain sufficient material for examination by free electrophoresis. A good example of this is the case of spinal fluid, concerning which considerable new information has been obtained by the use of paper electrophoresis (5,47,62). This has also proved true of the proteins in urine a large number of specimens has been studied... 

A number of the biologically active pituitary peptides have been studied successfully by means of filter paper electrophoresis. ACTH has been purified further and the biological activity in various fractions has been determined (45). Four different ACTH preparations obtained by this procedure have recently been reported (47). The hormones of the posterior pituitary have proved particularly suitable for analysis by micromethods on filter paper (44,74). Insufficient quantities of the purified hormones are as yet available for detailed studies by free electrophoresis. However, the relative homogeneity of the oxytocic and vasopressor hormones, purified by countercurrent distribution was readily ascertained by analyses on filter paper. The materials migrated as a round spot over a wide pH range (Fig. 4). The hormones were demonstrated to be amphoteric and the ap-... 

Another difficulty encountered in filter paper electrophoresis for isolation purposes is the failure to obtain 100% recovery of protein from the filter paper when ordinary nondenaturing solvents and simple soaking procedures are used. By employing the paper segments in a wicklike manner, as described by Sanger and Tuppy (60), better recoveries can be obtained by displacement. However, this is a tedious method and is technically difficult except on a microscale. 

The last few years zone electrophoresis, particularly using filter paper as a supporting medium, has found common use in biochemical and clinical investigations. The literature is growing rapidly, and it is not possible in this brief review to include all material that has been published. Filter paper electrophoresis will be dealt with in some detail, but it should be emphasized here that other supporting media often appear... 

A brief review of filter paper electrophoresis has been published by Lederer (1951). Grassman and Hannig (1952) have recently published a detailed discussion of the method in its application to the electrophoretic analysis of blood serum. 

The adsorption of negatively charged proteins is generally considerably lower than that of positively charged ones. The most suitable pH values for electrophoresis in ordinary filter paper are therefore those above the isoelectric points of the proteins. At low pH s the separations are often very bad. This fact considerably limits the use of filter paper electrophoresis. 

Great care should be exercised in the interpretation of the results of filter paper electrophoresis experiments, when studying the homogeneity of proteins, enzymes, etc. It must be remembered that the method involves several pitfalls. Control experiments for determination of the mobilities of the isolated components are easily made and are necessary to obtain conclusive evidence of the resolution. 

An electrode apparatus eonsists of a high-voltage supply, electrodes, buffer, and a support for the buffer such as filter paper (filter paper electrophoresis). 

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