We always add buffer solutions when performing DNA electrophoresis. Commonly used buffer solutions include TAE, which contains Tris, acetate and EDTA, and TBE (Tris-borate-EDTA).
What is the role of the buffer? One of the functions of the buffer is to maintain the pH of the solution stable. When an electric current passes through water, an oxidation reaction occurs at the anode to generate oxygen and hydrogen ions; a reduction reaction occurs at the cathode to generate hydrogen and hydroxide ions. Long-term electrophoresis will make the anode acid and the cathode alkaline. A good buffer system should have a strong buffering capacity to keep the pH of the solution at both poles basically stable. Another function of the electrophoresis buffer is to make the solution have a certain conductivity to facilitate the migration of DNA molecules. DNA is an alkaline substance that is negatively charged during electrophoresis (buffer pH=8) and migrates from the negative electrode to the positive electrode.
Another component of the electrophoresis buffer is EDTA, the purpose of which is to chelate Mg2+ plasma and prevent the activation of DNase during electrophoresis. Since nuclease needs these ions, EDTA can hold these ions firmly to avoid nucleic acid degradation. But it should be noted that magnesium ions are also cofactors of many enzymes, such as restriction enzymes, DNA polymerases, etc., so the concentration of EDTA is generally not too high (usually around 1mM).
Desheng TRIS buffer packaging
So which one is better, TAE or TBE? In fact, which one should I use for DNA electrophoresis? It really depends on the purpose of your experiment. Let's take a look at the difference between the two.
1. The conductivity of TBE is greater than that of TAE. Therefore, compared with TAE, TBE is less likely to cause overheating in the electrophoresis tank. TBE is recommended for long-term electrophoresis.
2. Boric acid is an enzyme inhibitor, so if you need to separate electrophoresis DNA for digestion reaction, it is recommended to use TAE as the electrophoresis buffer solution
3. TBE is better for separating smaller fragments. For fragments smaller than 300bp, the migration speed in TBE is faster on a 2% agarose gel.
4. TAE is suitable for the separation of large fragments. Fragments larger than 2kb migrate faster in TAE (in 0.8% agarose gel), and the speed is about 10% faster than in TBE. TAE is more suitable for recovery of DNA Fragment. Compared with TBE, TAE has higher resolution for supercoiled DNA.
In summary, the question of whether TBE or TAE is better cannot be generalized. The most suitable buffer system should be selected according to the specific experimental purpose. The biological buffer developed by Desheng has a wide buffer range, and only this kind of buffer is used. The system can prepare buffers with a wide range of pH values, and can provide various specifications of packaging. Buy buffers at Desheng Biochemical, welcome to consult and purchase.
Contact Person: Miss. Ankiwang