Freimoser:Protocols:ProteinQuantification
Absorbance assays
- Absorbance at 280 nm
- Range: 20 micrograms to 3 mg
- Volume: Depends on cuvette - volumes range from 200 microliters to 3 ml or greater
- Accuracy: Fair
- Convenience: Excellent, if equipment available
- Major interfering agents: Detergents, nucleic acids, particulates, lipid droplets
- Absorbance at 205 nm
- Range: Roughly 1 to 100 micrograms
- Volume: Depends on cuvette - volumes range from 200 microliters to 3 ml or greater
- Accuracy: Fair
- Convenience: Very good
- Major interfering agents: Detergents, nucleic acids, particulates, lipid droplets
- Extinction Coefficient
Range: 20 micrograms to 3 mg Volume: Depends on cuvette - volumes range from 200 microliters to 3 ml or greater Accuracy: ~2% (very good) Convenience: Very good Major interfering agents: Detergents, nucleic acids, particulates, lipid droplets Colorimetric assays
Modified Lowry Range: 2 to 100 micrograms Volume: 1 ml (scale up for larger cuvettes) Accuracy: Good Convenience: Fair Major interfering agents: Strong acids, ammonium sulfate
Biuret Range: 1 to 10 mg Volume: 5 ml (scale down for smaller cuvettes) Accuracy: Good Convenience: Good Major interfering agents: Ammonium salts
Bradford assay Range: 1 to 20 micrograms (micro assay); 20 to 200micrograms (macro assay) Volume: 1 ml (micro); 5.5 ml (macro) Accuracy: Good Convenience: Excellent Major interfering agents: None
Bicinchoninic Acid (Smith) Range: 0.2 to 50 micrograms Volume: 1 ml (scale up for larger cuvettes) Accuracy: Good Convenience: Good Major interfering agents: Strong acids, ammonium sulfate, lipids
Amido Black method Range: 2 to 24 micrograms Volume: 2 ml Accuracy: Good Convenience: Poor Major interfering agents: None reported
Colloidal Gold Range: 20 to 640 nanograms Volume: 1 ml (scale up for larger cuvettes) Accuracy: Fair Convenience: Poor Major interfering agents: Strong bases