TBE buffer

TBEorTris/Borate/EDTA,is abuffer solutioncontaining a mixture ofTris base,boric acidandEDTA.

In molecular biology, TBE andTAEbuffers are often used in procedures involvingnucleic acids,the most common beingelectrophoresis.Tris-acid solutions are effective buffers for slightly basic conditions, which keep DNA deprotonated and soluble in water. EDTA is achelatorof divalentcations,particularly ofmagnesium(Mg²⁺). As these ions are necessary co-factors for many enzymes, including contaminantnucleases,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 asrestriction enzymesandDNA polymerases,its concentration in TBE or TAE buffers is generally kept low (typically at around 1mM).

More recently discovered substitutes for TBE and TAE buffers for electrophoresis are available.

Recipe (1 liter of 5X stock solution)

• 54 g ofTris base(CAS# 77-86-1, free base)
• 27.5 g ofboric acid(CAS# 10043-35-3)
• 20 ml of 0.5 MEDTA(CAS# 60-00-4) (pH8.0)

Adjust pH to 8.3 by HCl.

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

• LB buffer,lithium borate buffer, a similar buffer containing lithium ions in place of Tris
• TAE buffer,a similar buffer containing acetic acid in place of boric acid