- The composition and concentration of DNA loading dye can vary a lot. However, all DNA loading dyes contain two essential components:
- High-density reagent
- Tracking dye
- The simplest DNA loading dye contains at least one tracking dye and one high-density reagent. The most common and widely used DNA loading dye contains two tracking dyes and a high-density reagent.
- In addition to tracking dyes and high-density reagent, DNA loading dye can be supplemented with EDTA, SDS or Tris.
| Ingredients | Concentration(in 6x loading dye) | Remarks |
| High-density reagents: Usually a DNA loading dye contains one high-density reagent. Any of the following reagents can be added to the loading dye. | ||
| Glycerol | 60% (v/v) | Interact with borate of TBE electrophoresis buffer. Do not use it with the TBE buffer. |
| Sucrose | 40% (w/v) | Prone to mold-like growth |
| Ficoll 400 | 15% (w/v) | Can be stored at room temperature, quite stable |
| Tracking dyes: One or more tracking dyes can be added. | ||
| Bromophenol blue | Conc range: 0.03 – 0.5 % (w/v)Standard conc: 0.25% (w/v) | Migration corresponds to the migration of 4000 – 5000 bp long DNA fragments in 1% agarose gel |
| Xylene cyanol | Conc range: 0.03 – 0.5 % (w/v)Standard conc: 0.25% (w/v) | Migration corresponds to the migration of 4000 – 5000 bp long DNA fragments in 1% agarose gel |
| Orange G | Conc range: 0.15 – 0.5 % (w/v)Standard conc: 0.4% (w/v) | Migration corresponds to the migration of 40 – 45 bp long DNA fragments in 1% agarose gel |
| Optional/special purpose reagents | ||
| Tris.Cl (pH 7.6) | 10 mM | Maintain the pH of loading dye |
| EDTA | 60 – 100 mM | Protect DNA from DNA modifying enzymes by sequestering divalent cations |
| SDS | 1% | Removes tertiary structure of DNA and eliminate protein from DNA |
REFERENCES
- Sciarra & Elliott, 1960. A solubility study of the boric acid-glycerin complex. I. Solubility of boric acid in glycerin solution at 25 degrees. J Am Pharm Assoc Am Pharm Assoc. 49, 115-117. PMID-13854731; Full Text Links: wiley, readcube, booksc
Was this post helpful?
Let us know if you liked the post. That’s the only way we can improve.
1 thought on “Composition and Ingredients of DNA Loading Dye”