Design and synthesis of metabolic chemical reporters for the visualization and identification of glycoproteins

Glycosylation events play an invaluable role in regulating cellular processes including enzymatic activity, immune recognition, protein stability, and cell–cell interactions. However, researchers have yet to realize the full range of glycan mediated biological functions due to a lack of appropriate chemical tools. Fortunately, the past 25 years has seen the emergence of modified sugar analogs, termed metabolic chemical reporters (MCRs), which are metabolized by endogenous enzymes to label complex glycan structures. Here, we review the major reporters for each class of glycosylation and highlight recent applications that have made a tremendous impact on the field of glycobiology.