TBE

Purpose

• TBE or Tris/Borate/EDTA is used for electrophoresis of nucleic acids in sequencing PAA gels or agarose gels.

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 conditions, which keep DNA deprotonated and soluble in water. EDTA is a chelator of divalent cations, particularly of magnesium (Mg²⁺). As these ions are necessary co-factors for many enzymes, including contaminant nucleases, the role of the EDTA is to protect the nucleic acids against enzymatic degradation. But since Mg²⁺ is also a co-factor for many useful DNA-modifying enzymes such as restriction enzymes and DNA polymerases, its concentration in TBE or TAE buffers is generally kept low (typically at around 1 mM).

Recipe

10x TBE (1 liter):

1. Dissolve 108 g Tris and 55 g Boric acid in 900 ml distilled water.
2. Add 40 ml 0.5 M Na₂EDTA (pH 8.0) (alternatively use 9.3 g Na₂EDTA)
3. Adjust volume to 1 Liter.
4. Store at room temperature.

Note: 10x TBE may take some time to dissolve, even with fast stirring

1x TBE (1 liter):

1. Dissolve 10.8 g Tris and 5.5 g Boric acid in 900 ml distilled water.
2. Add 4 ml 0.5 M Na₂EDTA (pH 8.0)
3. Adjust volume to 1 Liter.
4. Store at room temperature.

Note: 0.5x TBE may also be used for electrophoresis.

Commercial sources

1. UltraPure™ 10X TBE Buffer from Invitrogen