ELECTROPHORESIS

Method used in clinical and research laboratories for separating molecules according their size and electrical charge. Electrophoresis is used to separate large molecules (such as DNA fragments or proteins) from a mixture of molecules. An electric current is passed through a medium containing the mixture of molecules. Each kind of molecule travels through the medium at a different rate, depending on its electrical charge and molecular size. Separation of the molecules is based on these differences. Although many substances including starch gels and paper have historically served as media for electrophoresis, agarose and acrylamide gels are the media commonly used for electrophoresis of proteins and nucleic acids.