Protein Digestion Techniques

  • Daniel C. Liebler


Modern MS instruments are capable of measuring the molecular weights of intact proteins with a fairly high degree of accuracy. So why not do proteomics simply by measuring the masses of intact proteins? Unfortunately, intact mass measurements are of relatively little use for three reasons. First, as good as MS instruments are, there are still errors in the measurements they produce. The greater the mass of the protein, the greater the absolute magnitude of the error. Those errors introduce enough uncertainty to make the measurements insufficiently accurate for definitive identification. Moreover, diverse posttranslational modifications further complicate assignments based on mass. Second, not all proteins are amenable to intact mass measurements. It can be very difficult to obtain mass measurements on very large and hydrophobic proteins. Third, the sensitivity of measurements of intact protein masses is not nearly as good as sensitivity for peptide mass measurements and peptide tandem MS analyses. For these reasons, doing proteomics by analyzing intact proteins is not a realistic option at present.


Mass Measurement Intact Protein Cyanogen Bromide Cleavage Specificity Mass Spectrometric Sequencing 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Suggested Reading

  1. Jensen, O. N., Wilm, M., Shevchenko, A., and Mann, M. (1999) Sample preparation methods for mass spectrometric peptide mapping directly from 2-DE gels. Methods Mol. Biol. 112, 513–530.PubMedGoogle Scholar
  2. Shevchenko, A., Wilm, M., Vorm, O., and Mann, M. (1996) Mass spectrometric sequencing of proteins silver-stained polyacrylamide gels. Anal. Chem. 68, 850–858.PubMedCrossRefGoogle Scholar
  3. Walker, J. M. (1996) Protein Protocols Handbook. Humana Press, Totowa, NJ.Google Scholar

Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • Daniel C. Liebler
    • 1
  1. 1.College of PharmacyThe University of ArizonaTucsonUSA

Personalised recommendations