Polyacrylamide gel electrophoresis (PAGE) is a widely used laboratory technique employed to separate and analyze proteins or nucleic acids based on their size and charge. It is typically performed in a gel matrix composed of cross-linked polyacrylamide, which forms a porous network that acts as a molecular sieve.
In PAGE, an electric current is applied to the gel, causing charged molecules to migrate through the gel matrix. Size separation occurs as smaller molecules can move more easily through the pores, while larger molecules encounter greater resistance and migrate more slowly. Consequently, the gel acts as a molecular sieve, allowing the separation of different molecules based on their molecular weight.
The process of PAGE involves several steps. Firstly, a gel is prepared by polymerizing acrylamide and bisacrylamide monomers to create a solid matrix with defined pore sizes. This matrix is then loaded into a casting apparatus to form a gel slab. Secondly, samples containing the molecules of interest are mixed with a loading dye, which aids in monitoring the electrophoretic progress visually. The samples are loaded into the wells on the gel, followed by the application of an electric field. The molecules then migrate through the gel matrix according to their size and charge. Finally, after the electrophoresis run, the gel is stained or subjected to further analyses to visualize and quantify the separated molecules.
Polyacrylamide gel electrophoresis finds extensive applications in various scientific fields, including molecular biology, biochemistry, and genetics. It is commonly used to analyze protein samples, DNA fragments, and RNA molecules, providing valuable information about their size, purity, and molecular interactions.
