Activity-Based Protein Profiling Using Click Chemistry

A "tag-free" strategy for activity-based protein profiling using the azide-alkyne cycloaddition reaction (click chemistry). Proteins are first labeled by an azido-sulfonate ester probe and then treated with a fluorescent alkyne-tag under click-chemistry conditions (tag=Rhodamine, TCEP=tris(carboxyethyl)phosphine). Image by Anna Speers.