Protein quantitation methods and protein concentration determination protocols or assays. Includes the Lowry protein assay, the Bradford protein assays, UV spectrophotometric protein concentration determination and other methods.
Protein Quantitation Concentration Protocols Protocol Links
Absorbance Assay 205 nm Absorbance assay at 280 nm. This method is just as convenient as for absorbance at 280 nm. It may be preferred if there is excessive contamination by nucleic acids, since nucleic acids absorb very little radiation at 205 nm. Setting the wavelength is a bit tricky since 205 nm is right on the shoulder of the protein peak.
Absorbance Assay 280 nm Absorbance assays are fast and convenient, since no additional reagents or incubations are required. No protein standard need be prepared. The assay does not consume the protein. The relationship of absorbance to protein concentration is linear. Because different proteins and nucleic acids have widely varying absorption characteristics there may be considerable error, especially for unknowns or protein mixtures.
List of Protein Assays Find a list of assays for the determination of protein concentration in a solution. This list includes the sensitivity range, volume/amount of sample needed, subjective comments on accuracy and convenience, and major interfering agents. Procedural details, equipment requirements, and references are outlined in the individual assay documents.
UV Absorbance 280 nm Protein Determination UV Absorbance 280 nm Protein Determination. Simple and quick method to accurately quantitate total protein in purified material or approximately quantitate total protein in crude lysates or partial purified material. Quantitation of the amount of protein in a solution is possible in a simple spectrometer. Absorption of radiation in the near UV by proteins depends on the Tyr and Trp content (and to a very small extent on the amount of Phe and disulfide bonds). Dr. Mario Lebendiker