TE buffer is a commonly used buffer solution in molecular biology, especially in procedures involving DNA, cDNA or RNA. "TE" is derived from its components: Tris, a common pH buffer, and EDTA, a molecule that chelates cations like Mg2+. The purpose of TE buffer is to solubilize DNA or RNA, while protecting it from degradation.
Recipe
A typical recipe for making 1X TE buffer is:
TE buffer is also called as T10E1 Buffer, and read as "T ten E one buffer". To make a 100 ml solution of T10E1 Buffer, 1 ml of 1 M Tris-HCl (pH 8.0) and 0.2 ml EDTA (0.5 M) and made up with double distilled water up to 100ml.
Based on nuclease studies from the 1980s, the pH is usually adjusted to 7.5 for RNA and 8.0 for DNA. The respective DNA and RNA nucleases are supposed to be less active at these pH values, but pH 8.0 can safely be used for storage of both DNA and RNA.
EDTA further inactivates DNAse, by binding to metal cations required by this enzyme.
Genomic and plasmid DNA can be stored in TE Buffer at 4 °C (39.2 °F) for short-term use, or -20 °C (-4 °F) to -80 °C (-112 °F) for long-term storage. Repeated freeze-thaw cycles should be avoided.