TBE buffer

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TBE or Tris/Borate/EDTA, is a buffer solution containing a mixture of Tris base, boric acid and EDTA.

Contents

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).

According to studies by Brody and Kern, sodium boric acid [a] is a superior and cheaper conductive media for most DNA gel electrophoresis applications. [1] [2]

Recipe (1 liter of 5X stock solution)

Adjust pH to 8.3 by HCl. [3]

TBE can be diluted to 1X prior to use in electrophoresis, 0.5x is acceptable as well. Higher concentrations will result in poor results due to excessive heat generation.

See also

Notes

  1. 5 mM disodium borate decahydrate or 10 mM sodium hydroxide, pH adjusted to 8.5 with boric acid.

References

  1. Brody, J.R.; Kern, S.E. (2004). "History and principles of conductive media for standard DNA electrophoresis" (PDF). Anal Biochem. 333 (1): 1–13. doi:10.1016/j.ab.2004.05.054. PMID   15351274.
  2. Brody, Jonathan R.; Kern, Scott E. (February 2004). "Sodium boric acid: a Tris-free, cooler conductive medium for DNA electrophoresis". BioTechniques. 36 (2): 214–216. doi: 10.2144/04362BM02 .
  3. "5X TBE(1.1M Tris; 900mM Borate; 25mM EDTA; pH 8.3)" (PDF). Archived from the original (PDF) on 2017-11-07.