Medicago

Medicago AB Products Are Available Worldwide. For Research Use Only. In molecular biology, Tris-Borate-EDTA (TBE) Buffer Powder and TAE buffers are often used in procedures involving nucleic acids, the most common being agarose and polyacrylamide gel electrophoresis. Tris-acid solutions are effective buffers for the slightly basic conditions that keep DNA deprotonated and soluble in water. EDTA is a chelating agent for divalent cations, particularly magnesium (Mg2+). As these ions are necessary co-factors for many enzymes, including contaminant nucleases, one task of EDTA is to protect the nucleic acids against enzymatic degradation by nucleases. However, since Mg2+ is also a co-factor for many DNA-modifying enzymes such as restriction enzymes and DNA polymerases, its concentration in TBE or TAE buffers is generally kept low. Borate is a strong inhibitor for many enzymes, which makes its presence in TBE buffer very popular: the DNA sample run in a TBE buffer can better keep its integrity, which suits the purpose of many agarose gel electrophoreses runs, i.e. to analyze the size of DNA fragments. TBE buffer is often used for agarose and polyacrylamide gel electrophoresis when analysing DNA fragments from PCR amplification, DNA isolation protocols, or DNA cloning experiments. It is particularly useful for separating smaller DNA fragments (less than 1500 bp on a 0.8% agarose gel), e.g. small products of restriction enzyme digests. TBE has a greater buffering capacity and will give sharper resolution than TAE. DNA fragments also move faster in TBE than in TAE buffer. However, TBE gels in general afford a poor recovery of nucleic acids compared with TAE gels. TBE also inhibits DNA ligase, which may cause problems if subsequent DNA purification and ligation steps are intended. TBE buffer is supplied in 3 concentrations. Pre-weighed powders give 10x and 5x stock solutions or a 1x working solution.