Phosphopeptides - Chemical Synthesis, Analysis, Outlook and Limitations.

Protein phosphorylation is one of the most important post-translational events in cell regulation and signal transduction. Since the isolation of phosphorylated peptides from biological sources is usually not feasible, there is a need for efficient chemical phosphorylation methods to allow the study of the role of phosphorylation/dephosphorylation in biological processes. The recent developments in phosphopeptide chemistry (special protecting groups for the phosphate moiety and new amidite reagents) have provided peptide chemists with a wide variety of different strategies applicable for work with the sensitive phosphoserine, phosphothreonine and phosphotyrosine-containing peptides. This has made possible the efficient chemical preparation of longer, multiply phosphorylated, possibly cell-permeable or fluorescent residue-bearing peptides.