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.

* * *

The movement of particles in an electric field toward an electric pole (anode or cathode); used to separate and purify biomolecules. SEE ALSO: electropherogram. SYN: dielectrolysis, ionophoresis, phoresis (1). [electro- + G. phoresis, a carrying]

- capillary zone e. (CZE) a method for separating molecules extremely rapidly based on their electrophoretic mobility.

- carrier e. e. done on a carrier (such as paper, polyacrylamide gel, etc.).

- disk e. a modification of gel e. in which a discontinuity (pH, gel pore size) is introduced near the origin to produce a lamina (disk) of the materials being separated; the separating bands retain their discoid shape as they move through the gel.

- free e. e. of substances placed in a solution in a U-shaped tube.

- gel e. e. through a gel, usually a cylindrical tube or on a slab consisting of a gel of uniform composition.

- isoenzyme e. electrophoretic separation of serum enzymes; separation of lactate dehydrogenase and creatine phosphokinase is commonly used for diagnosis of acute myocardial infarction.

- lipoprotein e. electrophoretic separation of plasma lipoproteins.

- polyacrylamide gel e. (PAGE) a gel formed by cross-linking of acrylamide that is used for the separation of proteins or nucleic acid s. These substances are separated on the basis of both size and charge.

- pulsed-field gel e. SYN: pulse-field gel e..

- pulse-field gel e. gel e. in which, after electrophoretic migration has begun, the current is briefly stopped and reapplied in a different orientation; allows for the purification of long DNA molecules. SYN: pulsed-field gel e..

- thin-layer e. (TLE) electrophoretic migrations (separations) through a thin layer of inert material, such as cellulose, supported on a glass or plastic plate.

* * *

elec·tro·pho·re·sis -trə-fə-'rē-səs n, pl -re·ses -.sēz the movement of suspended particles through a fluid or gel under the action of an electromotive force applied to electrodes in contact with the suspension called also cataphoresis

elec·tro·pho·ret·ic -'ret-ik adj

elec·tro·pho·ret·i·cal·ly -i-k(ə-)lē adv

* * *

n.

the technique of separating electrically charged particles, particularly proteins, in a solution by passing an electric current through the solution. The rate of movement of the different components depends upon their charge, so that they gradually separate into bands. Electrophoresis is widely used in the investigation of body chemicals, such as the analysis of the different proteins in blood serum.

* * *

elec·tro·pho·re·sis (e-lek″tro-fə-reґsis) [electro- + phoresis] the separation of ionic solutes based on differences in their rates of migration in an applied electric field. electrophoretic adj