Click Chemistry‐Led Advances in High Content Functional Proteomics

The availability of complete genome sequences for numerous eukaryotic and prokaryotic organisms has inspired the advent of new methods to functionally characterize proteins on a global scale. Chemical approaches, in particular, have emerged as a powerful way to investigate the proteome, providing small‐molecule probes that report on protein activity and Post‐Translational Modification (PTM) state directly in complex biological samples. Many of the key advances made in chemical proteomics can be attributed to the development of efficient bio‐orthogonal reactions such as the copper (I)‐catalyzed Huisgen's azide–alkyne cycloaddition, a reaction commonly known as “Click Chemistry” (CC). The generation of “clickable” proteomics probes has removed the requirement for bulky reporter tags, thereby allowing access to more biologically relevant systems such as live cells or animals. The versatility of CC has also allowed for greater experimental efficiency, as different reporter tags (i.e., a fluorophore for detection or biotin for enrichment) can be appended to a single probe. Such advances have enabled researchers to identify protein activities dysregulated in disease states, assess the selectivity of enzyme inhibitors in vivo, and inventory specific PTMs on a proteome‐wide scale.