Activity-based protein profiling (ABPP) is a modern strategy
of chemical biology that overcomes several of these limitations
by applying molecular probes to profile active enzymes in
complex proteomes.15–18 In addition to its use as a tool for
functional characterization of proteins, ABPP provides also
a powerful method to unravel the molecular targets of natural
products and synthetic drugs alongside potential off-targets in
a living organism. The concept of ABPP relies on small molecules
that target the active site of specific enzymes and become covalently
bound either by their mechanism of enzyme inhibition or
by additional photo-cross-linking moieties like benzophenone or
diazirine