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Electrophoresis

Paper Electrophoresis

This technique is useful for the separation of small charged molecules such as amino acids and small proteins. A strip of filter paper is moistened with buffer and the ends of the strip are immersed into buffer reservoirs containing the electrodes. The samples are spotted in the center of the paper, high voltage is applied, and the spots migrate according to their charges. After electrophoresis, the separated components can be detected by a variety of staining techniques, depending upon their chemical identity.

Electrophoretic techniques have also been adapted to other applications such as the determination of protein isoelectric points. Affinity gels with biospecific properties are used to study binding sites and surface features of proteins. Continuous flow electrophoresis is applied to separations in free solution and has found very useful application in blood cell separation. Recently, High Performance Capillary Electrophoresis (HPCE) has been developed for the separation of many classes of biological molecules.

Resources

Books

Lodish, H., et al. Molecular Cell Biology. 4th ed. New York: W. H. Freeman & Co., 2000.

Nelson, David L., and Michael M. Cox. Lehninger Principles of Biochemistry. 3rd ed. Worth Publishing, 2000.

Westheimer, Reiner. Electrophoresis in Practice. 3rd ed. New York: Springer Verlag, 2001.

Organizations

Human Proteome Organization. <http://www.hupo.org/.>


Leonard D. Holmes

KEY TERMS

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Biological activity

—The specific biochemical function of a biomolecule such as enzyme affinity for a substrate.

Biomolecule

—An organic compound present in living organisms.

Electrophoresis gel

—A natural or synthetic polymer matrix used as a support for sample separation in electrophoresis.

Isoelectric point

—The pH at which a molecule has no electric charge and does not move in an electric field.

Molecular sieving

—The restriction of molecules migrating through a gel due to their size.

Sodium dodecyl sulfate (SDS)

—A negatively charged detergent which strongly binds to amino acid residues of protein and denatures the protein.

Additional topics

Science EncyclopediaScience & Philosophy: Dysprosium to Electrophoresis - Electrophoretic TheoryElectrophoresis - Electrophoretic Theory, Methodology And Applications, Gel Electrophoresis, Gel Electrophoresis Of Dna, Gel Electrophoresis Of Proteins