Agarose gel electrophoresis is the most commonly used method for the size- and shape-based separation of dna molecules comprising several hundred or more base pairs, including plasmid dna molecules. Agarose is one of the main components of agar extracted from the cell wall of red algae. Agarose is a linear polysaccharide composed of galactose and anhydro-galactose units.
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Agarose is a polysaccharide, generally extracted from certain red seaweed.[1] It is a linear polymer made up of the repeating unit of agarobiose, which is a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose.[2] Agarose is one of the two principal components of agar, and is purified from agar by removing agar's other component, agaropectin.[3]
Agarose is frequently used in molecular biology for the separation of large molecules, especially DNA, by electrophoresis. Slabs of agarose gels (usually 0.7 - 2%) for electrophoresis are readily prepared by pouring the warm, liquid solution into a mold. A wide range of different agaroses of varying molecular weights and properties are commercially available for this purpose. Agarose may also be formed into beads and used in a number of chromatographic methods for protein purification.