TAE buffer
Encyclopedia
TAE buffer is a buffer solution
Buffer solution
A buffer solution is an aqueous solution consisting of a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. It has the property that the pH of the solution changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a...

 containing a mixture of Tris base, acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

 and EDTA
EDTA
Ethylenediaminetetraacetic acid, widely abbreviated as EDTA , is a polyamino carboxylic acid and a colourless, water-soluble solid. Its conjugate base is named ethylenediaminetetraacetate. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ligand...

.

In molecular biology it is used in agarose electrophoresis
Electrophoresis
Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...

 typically for the separation of nucleic acids such as DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 and RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

. It is made up of Tris-acetate buffer, usually at pH 8.0, and EDTA
EDTA
Ethylenediaminetetraacetic acid, widely abbreviated as EDTA , is a polyamino carboxylic acid and a colourless, water-soluble solid. Its conjugate base is named ethylenediaminetetraacetate. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ligand...

, which sequesters divalent cations. TAE has a lower buffer capacity than TBE
TBE Buffer
TBE or Tris/Borate/EDTA, is a buffer solution containing a mixture of Tris base, boric acid and EDTA.In molecular biology, TBE and TAE buffers are often used in procedures involving nucleic acids, the most common being electrophoresis. Tris-acid solutions are effective buffers for slightly basic...

 and can easily become exhausted, but linear, double stranded DNA runs faster in TAE.

Recently, Brody & Kern simplified electrophoretic buffers by substituting TBE and TAE buffers for a more efficient and inexpensive conductive media in gel systems.

Uses

TAE (Tris-acetate-EDTA) buffer is used as both a running buffer and in agarose gel. Its use in denaturing gradient gel electrophoresis
Gel electrophoresis
Gel electrophoresis is a method used in clinical chemistry to separate proteins by charge and or size and in biochemistry and molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge...

 methods for broad-range mutation analysis has also been described. TAE has been used at various concentrations to study the mobility of DNA in solution with and without sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

. However, high concentration of sodium chloride (and many other salts) in a DNA sample retards its mobility. This may lead to incorrect interpretations of the resulting DNA banding pattern.

Compared with TBE buffer
TBE Buffer
TBE or Tris/Borate/EDTA, is a buffer solution containing a mixture of Tris base, boric acid and EDTA.In molecular biology, TBE and TAE buffers are often used in procedures involving nucleic acids, the most common being electrophoresis. Tris-acid solutions are effective buffers for slightly basic...

, TAE buffer offers advantages in subsequent enzymatic applications for the DNA sample. For example, if a DNA sample is going to be used in a cloning experiment, the step that follows its running on an agarose gel is to ligate (covalently link) to a cloning vector (most likely a plasmid). DNA sample from TAE Buffer is suitable for this purpose, while DNA from TBE buffer is not. Borate in the TBE buffer is a strong inhibitor for many enzymes. This enzyme inhibiting property made TBE buffer
TBE Buffer
TBE or Tris/Borate/EDTA, is a buffer solution containing a mixture of Tris base, boric acid and EDTA.In molecular biology, TBE and TAE buffers are often used in procedures involving nucleic acids, the most common being electrophoresis. Tris-acid solutions are effective buffers for slightly basic...

very popular in its realm for two reasons. First, a DNA sample run in a TBE buffer can better keep its integrity. The other main reason is that the purpose for many agarose gel electrophoreses is to analyze the size of DNA molecules.

Preparation

TAE buffer is commonly prepared as a 50X stock solution for laboratory use. A 50X stock solution can be prepared by dissolving 242g Tris base in water, adding 57.1mL glacial acetic acid, and 100mL of 500mM EDTA (pH 8.0) solution, and bringing the final volume up to 1 liter. This stock solution can be diluted 50:1 with water to make a 1X working solution. This 1X solution will contain 40mM Tris, 20mM acetic acid, and 1mM EDTA.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK