TBE buffer

{{Short description|Concept in molecular biology}}

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 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{{efn|5 mM disodium borate decahydrate or 10 mM sodium hydroxide, pH adjusted to 8.5 with boric acid.}} is a superior and cheaper conductive media for most DNA gel electrophoresis applications.{{cite journal | last1 = Brody | first1 = J.R. | last2 = Kern | first2 = S.E. | year = 2004 | title = History and principles of conductive media for standard DNA electrophoresis | url = http://www.cc.ahs.chula.ac.th/Molmed/DNA%20electro%27s%20conductive%20media.pdf | journal = Anal Biochem | volume = 333 | issue = 1| pages = 1–13 | doi = 10.1016/j.ab.2004.05.054 | pmid=15351274}}{{cite journal |last1=Brody |first1=Jonathan R. |last2=Kern |first2=Scott E. |title=Sodium boric acid: a Tris-free, cooler conductive medium for DNA electrophoresis |journal=BioTechniques |date=February 2004 |volume=36 |issue=2 |pages=214–216 |doi=10.2144/04362BM02|doi-access=free }}