Fig. 2From: Advancing understanding of microbial bioenergy conversion processes by activity-based protein profilingRepresentative mechanisms for labeling of glycoside hydrolase enzymes by a variety of probe types. In each image the orange shape represents a target enzyme. a Photoreactive diazirine-functionalized probes work by probe intercalation into the substrate binding site, followed by UV irradiation and formation of a carbene that performs C–H insertion into the peptide of the target protein. Subsequent click chemistry is used for characterization of probe targets, e.g., by imaging or mass spectrometry. b Following association of the probe into the substrate binding region of the enzyme, the electrophilic iodoacetamide moiety of the probe reacts with a nucleophilic amino acid residue of the enzyme in a classic nucleophilic displacement reaction. c Mechanism-based probes work by directly interrogating the catalytic machinery of the enzymes, resulting in a covalent complex between probe and enzymeBack to article page