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What Is Electrophoresis Used For?

Electrophoresis is a technique that separates biomolecules according to properties such as size, shape or charge. Life scientists use electrophoresis both to analyze samples and to purify biomolecules such as proteins and nucleic acids.

  1. Analyzing Protein Samples

    • Electrophoresis is useful for analyzing protein samples. Most proteins carry a negative charge in a slightly basic solution; thus, they will migrate through a gel with speed characteristics of their size. Because proteins have complex three-dimensional folded structures, it is necessary to add a mild solvent to denature the proteins through disrupting the interactions.

    DNA Electrophoresis

    • Electrophoresis is also used when DNA is involved. Deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) fragments of different sizes can be separated using either agarose gel electrophoresis or polyacrylamide gel electrophoresis, depending on the approximate molecular weight of the fragments.

    Pulsed-Field Gel Electrophoresis

    • For large DNA molecules--those that are between hundreds of thousands and millions of base pairs long--pulsed-field gel electrophoresis is used instead. This allows the forward direction to be interrupted by shorter pulses in the opposite direction.

    Alternating-Field Electrophoresis

    • When DNA needs to be separated, alternating-field electrophoresis is used. This type of electrophoresis is separation of the very large molecules of DNA. A portion of DNA varies in size from 40 to 20,000 kilobase pairs. For the average biologist, this is a big breakthrough, because it allows the separating of DNA in larger numbers.

    Displacement Electrophoresis

    • When analyzing small volumes, displacement electrophoresis often is used. Displacement electrophoresis has the ability to analyze extremely small concentrations. This makes it possible to use samples for many different studies.

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