Description
TBE Buffer (5X) is a solution used in Agarose Gel Electrophoresis (AGE) typically for the separation of nucleic acids (i.e. DNA and RNA). Tris-Borate-EDTA (TBE) is not only used in nucleic acid agarose and polyacrylamide gel electrophoresis but also in agarose and polyacrylamide gel preparation. DNA mobility on AGE is known to depend on the composition and strength of electrode buffer as well as the agarose concentrations. Although the DNA fragments were generally believed to migrate faster in TAE than in TBE, under some circumstances and paradoxically this was not always the case. The higher mobility of small fragments in TBE may be attributed to the formation of non-specific, highly charged deoxyribose-borate complexes. The resolution of supercoiled DNA is better in TAE than TBE but TAE's buffering capacity is rather low as it tends to become exhausted during successive electrophoresis.
TAE buffer is more useful for larger DNA fragments (<2.0kb) but TBE is more effective to obtain higher resolution of smaller DNA fragments (i.e. 300bp). Either buffer is adequate is applicable for middle-sized DNA fragments. TBE not only has a more stable and higher buffering capacity when compared to the more conventional TAE but also more advantageous for obtaining a higher resolution of smaller DNA fragments on agarose gels.
