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 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).

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

Recipe (1 liter of 5X stock solution)
Adjust pH to 8.3 by HCl.
 * 54 g of Tris base (CAS# 77-86-1, free base)
 * 27.5 g of boric acid (CAS# 10043-35-3)
 * 20 ml of 0.5 M EDTA (CAS# 60-00-4) (pH 8.0)

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.