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The basic principle of electrophoresis

  • Author:naky
  • Source:www.diecastingpartsupplier.com
  • Release on:2014-12-09
Electrophoresis

The basic principle of electrophoresis

Electrophoresis refers to the process of the charged particles migrate in an electric field . Many important biological molecules , such as amino acids , peptides, proteins , nucleotides , nucleic acids and so having ionizable groups , they may be positively or negatively charged at a specific pH, under the action of the electric field , the charged brought its molecules move toward the opposite electrode charge polarity direction . Electrophoresis technique is the use in the electric field , the molecule itself and the difference due to size, shape, and other properties of the various molecules to be separated in the charging properties of the sample , the charged molecules have different migration rates , and thus the samples were isolated , identified or purified technology.

Electrophoresis process must be carried out in a support medium. Tiselius et al. 1937 free interface electrophoresis carried no fixed support medium , so the diffusion and convection than the strong impact of separation. So there is a fixed support medium of electrophoresis , the sample was subjected to electrophoresis process in a fixed medium , reducing the interference effect diffusion and convection . Initial support medium is paper and cellulose acetate membranes , currently these media in the laboratory has been applied less. For a long period of time , small molecules such as amino acids , peptides , sugars or the like is usually carried out using a filter paper of cellulose , silica gel thin layer plate for electrophoretic separation medium , analysis , but is generally using more sensitive techniques such as HPLC and the like analyzed. These media suitable for separation of small molecules , simple, and convenient. But for the separation of complex biological macromolecules less effective . Gel as a support medium introduced greatly promoted the development of electrophoresis technology, the technology has become an important means of electrophoretic analysis of proteins, nucleic acids and other biological macromolecules . Gel initially using starch gel , but most used agarose gel and polyacrylamide gel. Proteins using polyacrylamide gel electrophoresis major .

Electrophoresis apparatus consists of two parts: the power supply and the electrophoresis tank . DC power supply , generating an electric field driven migration of charged molecules in the electrophoresis tank . Electrophoresis tank can be divided into horizontal and vertical categories. Vertical plate electrophoresis is a more common form , commonly used in polyacrylamide gel electrophoresis of protein separation . Intermediate electrophoresis tank is clamped together, the two glass sheets , glass plates separated by a strip on both sides , in the middle of the glass plate prepared in gel electrophoresis , the gel size is typically 12cm & acute; 14 cm, a thickness of 1mm ~ 2 mm, in recent years, newly developed electrophoresis tank , plastic surface is smaller , thinner, shorter electrophoresis reagents and to save time.When you put glue in a plastic comb gel solution , after removing the rubber polymerization , forming a groove on the sample . Horizontal electrophoresis , the gel laying on the horizontal glass or plastic plate , with a thin layer of damp filter paper and connected gel electrophoresis buffer , or directly immersed in the gel buffer . Because changing the pH of charged molecules cause a change in the charge , thereby affecting its electrophoretic migration velocity , so the electrophoresis process to be carried out in a suitable buffer , the buffer can maintain stable charging properties to be isolate.