TE Buffer
Introduction
TE buffer (a.k.a Tris EDTA buffer) is one of the extensively used buffers in preparation and storage of DNA and RNA protocols. TE buffer is also known as T10E1 Buffer due to their ratio in the working concentration, which is 10mM and 1 mM respectively. As the name suggests, the TE buffer is composed of two reagents, i.e., Tris & EDTA. Tris takes the role of maintaining the buffering capacity, while the EDTA binds (chelating agent)and make the metal ions unavailable for traces of enzymes (if any) which might degrade DNA/ RNA. TE buffer is preferred over distilled water for storing DNA and RNA for a couple of properties. TE buffer is alkaline (DNA and RNA are relatively stable at pH8) and contains EDTA which helps in inactivation of DNases and RNases, which require metal ions for their activity.
Applications
- Used for Resuspension and long term storage of nucleic acids.
- Used in cloning reactions (eg., Gateway).
Composition
| Reagent (stocks) | Working concentration (1X) | add volume of reagent to make 1X (100mL) | add volume of reagent to make 10X (100mL) | add volume of reagent to make 50X (100mL) |
|---|---|---|---|---|
| 1M Tris (pH 8.0) | 10mM | 1 mL | 10 mL | 50 mL |
| 0.5M EDTA (pH 8.0) | 1mM | 0.2 mL | 2 mL | 10 mL |
| H2O | 98.8 mL | 88 mL | 40 mL |
Table 1.
pH
In most of the applications, pH 8.0 is desirable. Adding the solutions as specified in the table below, get the pH to 8.0 by default. In case of pH adjustment, use 0.5N HCl and 0.5N NaOH.
Preparation
Add the Tris (1M) and EDTA (0.5M) solutions, as mentioned in the table above. For adjusting volumes use dilution calculator.
Sterilize the buffer by autoclaving or by filter sterilization (0.2 µM).
Storage
Store the TE buffer at room temperature.
Points to be noted
- Add agar after adjusting the pH of the medium to avoid hydrolysis of agar.
- Protect the liquid medium and plates from light. Rose-bengal is light-sensitive, and its photodegradation product is toxic to fungi.
- Do not use the medium which is past its recommended storage time as the colony count can be affected.