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Quantitative and Qualitative Analysis of Posttranslationally Modified Proteins

Peptides and Proteins

  1. Joshua S. Sharp

Published Online: 15 SEP 2011

DOI: 10.1002/9780470027318.a9200

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Sharp, J. S. 2011. Quantitative and Qualitative Analysis of Posttranslationally Modified Proteins. Encyclopedia of Analytical Chemistry. .

Author Information

  1. University of Georgia, Complex Carbohydrate Research Center, Athens, GA, USA

Publication History

  1. Published Online: 15 SEP 2011


The majority of proteins are posttranslationally modified. Posttranslational modifications (PTMs) have been found to modify a wide variety of biological and biophysical properties, including structure, biophysical stability and dynamics, enzymatic activity, protein-protein interactions, protein-ligand interactions, and protein half-life within the cell. Virtually every analytical technique that can be used to analyze proteins in general can and has been used to analyze posttranslationally modified proteins. A vast array of both enzymatic and nonenzymatic protein modifications have been identified and characterized, which can make comprehensive analyses of all possible modifications difficult. Owing to the enormous scope of this topic, this article focuses on the analytical techniques that are probably most broadly applicable and widely used for wide-scale analyses of posttranslationally modified proteins, namely mass spectrometry (MS) coupled to various separations technologies. Some technical and experimental details on the analyses of three heavily studied classes of PTM have been provided — phosphorylation, N-linked glycosylation, and nonenzymatic oxidation. While we will be using these three classes of modifications in order to provide focus to our discussion, we will attempt to use these specific examples to illustrate broadly applicable techniques, as well as issues that often lead to difficulties and conflict between the experimental designs required for thorough quantitative and qualitative analyses of posttranslationally modified proteins.