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 cofactors 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 cofactor 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). TBE buffer is used to prepare agarose gels and as running buffer in agarose gel electrophoresis to separate and identify and analyse nucleic acids.
This protocol covers the steps involved in making 1L of 10x TBE buffer from Tris, Borate and EDTA powders