Electrophoresis Buffers
Electrophoresis buffers are essential molecular biology reagents used to create the ionic environment necessary to separate charged macromolecules (DNA, RNA, and proteins) through a gel matrix. They act as a conductive medium to carry the electric current while stabilizing the solution’s pH to prevent sample degradation.
Depending on your specific downstream application (e.g., DNA sequencing, cloning, or Western blotting), the standard electrophoresis buffers vary significantly in their composition.
Product Description
Below are the primary buffer categories and their standard descriptions:
- Nucleic Acid Running Buffers (Agarose/PAGE)
- TAE (Tris-Acetate-EDTA): Ideal for separating larger DNA fragments ( > 1 kb). It is the preferred buffer when DNA is to be recovered for downstream enzymatic applications (like cloning or ligation), as the borate in other buffers can inhibit enzymes.
- TBE (Tris-Borate-EDTA): Best suited for high-resolution separations of smaller DNA fragments ( < 1 kb). It has a higher buffering capacity and lower conductivity than TAE, keeping the gel cooler during extended runs.
- SGTB (Sodium/Guanidine/Tris-Borate): A low-conductance buffer formulated to run agarose gels at much higher voltages without overheating or melting the gel, enabling very rapid and sharp band resolution.
- Protein Running Buffers (PAGE / SDS-PAGE)
- Tris-Glycine-SDS: The standard buffer for denaturing polyacrylamide gel electrophoresis (SDS-PAGE). It unfolds proteins and imparts a uniform negative charge, allowing proteins to separate strictly by molecular weight.
- Tris-Glycine (Native): Formulated without SDS or reducing agents, this buffer is designed for separating proteins in their native, folded state so that charge-to-mass ratio and biological activity are maintained.
- MOPS / MES: Commonly used for pre-cast Bis-Tris gels to provide optimal separation of small to mid-sized proteins under denaturing conditions.
- Transfer & Sample Buffers
- Transfer Buffers (Blotting): Designed to move proteins or nucleic acids out of a gel and onto a membrane (e.g., PVDF or nitrocellulose). They typically contain Tris and Glycine (often with methanol added) for proteins.
- Loading / Sample Buffers: Added directly to the sample prior to pipetting. They contain tracking dyes (like bromophenol blue) to monitor the run’s progress and density agents (like glycerol or Ficoll) to make the sample sink into the gel well.
