Refinement of the Coomassie blue method of protein quantitation: A simple and linear spectrophotometric assay for ≤0.5 to 50 μg of protein
✍ Scribed by Thomas Spector
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- English
- Weight
- 279 KB
- Volume
- 86
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
The Coomassie brilliant blue Cl assay for proteins described by Bradford (1976) (Ana!. Biochem. 72, 248) was reexamined. It was found that the extinction coefficient of the dye-protein complex solution remained constant over the protein concentration range of 0.8 to 10 &ml of solution. This unchanging extinction coefficient, A,,, = 0.60 k O.Ol/lO pg of protein/ml of solution, enhances both the sensitivity and versatility of the assay. Selection of a volume of dye-reagent (0.5 to 5.0 ml) which dilutes the protein sample to a final concentration of 0.8 to 10 pg/ml permits the application of Beer's Law for accurate determinations of 50.5 to 50 pg of protein. A combination of Bradford's study and the present one indicates that most common laboratory reagents and chemicals exert little or no influence on the Asg5 of the dye-reagent.