TE
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TE is a shorter name for "Tris-EDTA". For the rest of the story, see TAE, Tris, and TBE.
Purpose
- TE buffer is often used to store DNA and RNA.
- EDTA in TE chelates Mg2+ and other divalent metals ions necessary for most causes of DNA and RNA degradation, suppressing these processes.
- Tris is a buffering agent to keep the solution at a defined pH.
Recipe 10x TE
| volume | reagent | final conc. |
| 100 ml | 1M Tris-HCl pH 7.5 or 8.0 (see notes) | 100 mM |
| 20 ml | 0.5M EDTA pH 8.0 | 10 mM |
| 880 ml | ddH2O |
Recipe 1x TE
| volume | reagent | final conc. |
| 10 ml | 1M Tris-HCl pH 7.5 or 8.0 (see notes) | 10 mM |
| 2 ml | 0.5M EDTA pH 8.0 | 1 mM |
| 988 ml | ddH2O |
→ 1x TE is 10 mM Tris-HCl and 1 mM EDTA
Notes
- For the Tris-HCl use Tris base and adjust to desired pH using HCl.
- TE buffer is often used to store DNA and RNA. The EDTA in TE chelates Mg2+ and other divalent metals ions necessary for most causes of DNA and RNA degradation, suppressing these processes. However, downstream reactions like restriction digests, PCR, ligations, and reverse transcription typically require Mg2+, potentially making the presence of EDTA in the reaction problematic. So, when using DNA or RNA that was suspended in TE, you should keep track of the amount of EDTA in the mix to make sure there is still enough Mg2+ for subsequent reactions to proceed successfully. Each EDTA molecule chelates one Mg2+ ion.
- Some protocols use TE 10:0.1 with 0.1 mM EDTA to reduce the interaction of the EDTA with downstream applications.
- Some people use TE buffers with different pH's for different applications. For example, DNA is stored at pH 8 to reduce depurination, which is acid catalyzed, while RNA is stored at a slightly lower pH (7.5) because degradation of RNA is base-catalyzed. Most downstream reactions will not be influenced by the slightly different pH storage conditions.
- For dilution of primers water for injections can be used rather than TE.
