Fishing the PTM proteome with chemical approaches using functional solid phases

Post-translational modifications (PTMs) are covalent additions of functional groups to proteins and are known to play essential roles in biological processes. Covalently attached PTMs are usually present at substoichiometric levels, implying that a PTM proteome is often present in only a small fraction of the entire proteome. The low abundance of PTMs creates a tremendous analytical challenge for PTM proteomics. New analytical strategies, especially enrichment approaches, are required to allow the comprehensive determination of PTMs. Solid-phase capture of PTMs through chemical reactions provides the most specific approach for fishing the PTM proteome, and based on these chemical reactions, a variety of novel functional nanomaterials have been developed. This review mainly focuses on the currently available chemical approaches for investigating PTMs, as well as the functional solid phases used for PTM proteome separation.