Posttranslational Modifications of Proteins: Tools for Functional
Proteomics is a compilation of detailed protocols needed to detect and
analyze the most important co- and posttranslational modifications of
proteins. Though, for reasons of simplicity not explicitly mentioned in
the title, both kinds of modifications are covered, whether they occur
during, or after, biosynthesis of the protein. My intention was to cover
the most significant protein modifications, focusing on the fields of
protein function, proteome research, and the characterization of
pharmaceutical proteins. The majority of all proteins undergo co- and/or
posttranslational modifications. Knowledge of these modifications is
extremely important, since they may alter physical and chemical
properties, folding, conformation distribution, stability, act- ity,
and, consequently, function of the proteins. Moreover, the modification
itself can act as an added functional group. Examples of the biological
effects of protein mo- fications include: phosphorylation for signal
transduction, ubiquitination for p- teolysis, attachment of fatty acids
for membrane anchoring or association, glycosylation for protein
half-life, targeting, cell-cell and cell-matrix interactions, and
carboxylation in protein-ligand binding to name just a few. Full
understanding of a specific protein structure-function relationship
requires detailed information not only on its amino acid sequence, which
is determined by the corresponding DNA sequence, but also on the
presence and structure of protein modifications.
