Electroelution

Electroelution is a method used to extract a nucleic acid or a protein sample from an electrophoresis gel by applying a negative current in the plane of the smallest dimension of the gel, drawing the macromolecule to the surface for extraction and subsequent analysis.^[2] For example, electroblotting and preparative native PAGE are based upon the same principle.^[3][4]

Equipment for bioanalytical continuous-elution gel electrophoresis: electrophoresis chamber, peristaltic pump, fraction collector, buffer recirculation pump and UV detector (in a refrigerator), power supply and recorder (on a table).^[1]

DNA extraction

Using this method, DNA fragments can be recovered from a particular region of agarose or polyacrylamide gels. The gel piece containing the fragment is excised (cut out from the whole gel) and placed in a dialysis bag with buffer. Electrophoresis causes the DNA to migrate out of the gel into the dialysis bag buffer. The DNA fragments are recovered from this buffer and purified, using phenol–chloroform extraction followed by ethanol precipitation. This method is simple, rapid and yields high recovery (75%) of DNA fragments from gel pieces.^[3]

Protein extraction

Proteins are continuously eluted from a gel column and separated in different fractions according their isoelectric point.^[1] Preparative native PAGE yields more than 95% recovery of metalloproteins.^[4]

References

1. Kastenholz B, Garfin DE (2010). "Isolation of acidic, basic and neutral metalloproteins by QPNC-PAGE" (PDF). Nature Precedings: 1–4. doi:10.1038/npre.2010.4617.1.
2. Seelert H, Krause F (2008). "Preparative isolation of protein complexes and other bioparticles by elution from polyacrylamide gels". Electrophoresis. 29 (12): 2617–36. doi:10.1002/elps.200800061. PMID 18494038. S2CID 35874355.
3. Zarzosa-Álvarez, Ana L.; et al. (2010). "Electroeluting DNA Fragments". Journal of Visualized Experiments. 43 (43): 2136. doi:10.3791/2136. PMC 3157863. PMID 20834225.
4. Kastenholz, B (2004). "Preparative Native Continuous Polyacrylamide Gel Electrophoresis (PNC‐PAGE): An Efficient Method for Isolating Cadmium Cofactors in Biological Systems". Analytical Letters. 37 (4). Informa UK Limited: 657–665. doi:10.1081/al-120029742. ISSN 0003-2719. S2CID 97636537.