Biotech Basics: TAE or TBE 

Welcome to this blog post on the difference between TAE and TBE. While this may not seem like the most exciting topic, trust me, it’s electrifying!

First, let’s start with the basics. Gel electrophoresis is a technique used in laboratories to separate DNA, RNA, and protein molecules based on their size and charge. During an electrophoresis experiment, samples are loaded into wells (indentations) at one end of a gel, and then an electrical current is applied which pulls the samples through the gel.

Buffers serve two essential functions during this process. First, they provide the ions that allow the current to travel through the gel. Second, they maintain the pH throughout the experimental run, which is essential to keeping the structure and charge of the sample molecules stable. In addition, some buffers also chelate metal ions which can help prevent enzymatic degradation of DNA.

Now, let’s get to the main event – TAE and TBE. While both TAE and TBE carry a current, stabilize pH, and protect DNA, the chemical differences between the two can affect their resolution power, buffering capacity, and interactions with downstream enzymes.

TBE is a mixture of Tris base, boric acid, and EDTA. This mixture is a great conducive medium, so it’s the buffer of choice for long electrophoresis runs as it won’t overheat and unintentionally melt a gel. TBE also resolves small DNA fragments better, so researchers working with DNA fragments less than 2 kb reach for the TBE bottle.

On the other hand, TAE is a mixture of Tris base, glacial acidic acid, and EDTA. TAE is often used when isolating DNA samples via electrophoresis because borate, which is present in TBE, is an enzyme inhibitor and can have carryover effects, while acetic acid isn’t and doesn’t. In addition, large DNA fragments seem to separate better in TAE, so researchers reach for the TAE bottle when working with DNA fragments greater than 2 kb.

TAE and TBE differences are subtle but much more than a simple “A” or “B”. Next time you’re in the lab, reach for the TAE or TBE bottle with confidence, knowing that you’re using the right buffer for the job!

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