Agarose Gel Electrophoresis Agarose gels are commonly used to sort DNA and RNA molecules based on size. The agarose gel concentration can be varied, based on the size of the molecules that need to be isolated.SDS-PAGE Electrophoresis Sodium dodecyl sulfate - polyacrylamide gel electrophoresis is used to separate proteins based on size. The proteins are unfolded, or denatured, using SDS detergent, and run on a polyacrylamide gel.DNA Sequencing Gels Denatured DNA can be run on polyacrylamide gels, which allows scientists to determine the sequence of the molecule.Native Protein Electrophoresis Proteins can remain folded in the native conformation and run on gels to separate them by both mass and charge.Electrofocusing Electrophoresis Electrofocusing separates proteins on the basis of charge as well as pH; the gel used in this type of electrophoresis has a pH gradient.

Theory

PAGE (Polyacrylamide Gel Electrophoresis), is an analytical method used to separate components of a protein mixture based on their size. The technique is based upon the principle that a charged molecule will migrate in an electric field towards an electrode with opposite sign.The general electrophoresis techniques cannot be used to determine the molecular weight of biological molecules because the mobility of a substance in the gel depends on both charge and size. To overcome this, the biological samples needs to be treated so that they acquire uniform charge, then the electrophoretic mobility depends primarily on size. For this different protein molecules with different shapes and sizes, needs to be denatured(done with the aid of SDS) so that the proteins lost their secondary, tertiary or quaternary structure .The proteins being covered by SDS are negatively charged and when loaded onto a gel and placed in an electric field, it will migrate towards the anode (positively charged electrode) are separated by a molecular sieving effect based on size. After the visualization by a staining (protein-specific) technique, the size of a protein can be calculated by comparing its migration distance with that of a known molecular weight ladder(marker).

Gel electrophoresisis a method for separation and analysis of macromolecules (DNA,RNAandproteins) and their fragments, based on their size and charge.It is used in clinical chemistry to separate proteins by charge and/or size (IEF agarose, essentially size independent) and inbiochemistryandmolecular biologyto separate a mixed population ofDNAandRNAfragments by length, to estimate the size ofDNAandRNAfragments or to separateproteinsby charge.[1]Nucleic acid molecules are separated by applying anelectric fieldto move the negatively charged molecules through anagarosematrix. Shorter molecules move faster and migrate farther than longer ones because shorter molecules migrate more easily through the pores of the gel. This phenomenon is called sieving.[2]Proteins are separated by charge in agarose because the pores of the gel are too large to sieve proteins. Gel electrophoresis can also be used for separation of nanoparticles.Gel electrophoresis uses a gel as an anticonvective medium and/or sieving medium during electrophoresis, the movement of a charged particle in an electrical field. Gels suppress the thermal convection caused by application of the electric field, and can also act as a sieving medium, retarding the passage of molecules; gels can also simply serve to maintain the finished separation, so that a post electrophoresis stain can be applied.[3]DNA Gel electrophoresis is usually performed for analytical purposes, often after amplification of DNA viaPCR, but may be used as a preparative technique prior to use of other methods such asmass spectrometry,RFLP,PCR,cloning,DNA sequencing, orSouthern blottingfor further characterization.