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