Activity-based proteomics

[1] The basic unit of ABPP is the probe, which typically consists of two elements: a reactive group (RG, sometimes called a "warhead") and a tag.

The tag may be either a reporter such as a fluorophore or an affinity label such as biotin or an alkyne or azide for use with the Huisgen 1,3-dipolar cycloaddition (also known as click chemistry).

[2] A major advantage of ABPP is the ability to monitor the availability of the enzyme active site directly, rather than being limited to protein or mRNA abundance.

With classes of enzymes such as the serine hydrolases[3] and metalloproteases[4] that often interact with endogenous inhibitors or that exist as inactive zymogens, this technique offers a valuable advantage over traditional techniques that rely on abundance rather than activity.

[5] In recent years ABPP has been combined with tandem mass spectrometry enabling the identification of hundreds of active enzymes from a single sample.

Fluorophosphonate - rhodamine (FP-Rhodamine) activity-based probe for profiling of the serine hydrolase superfamily. In this probe the fluorophosphonate is the reactive group (RG) as it binds irreversibly to the active-site serine nucleophile of serine hydrolases and the tag is rhodamine , a fluorophore for in- gel visualization.
In- gel ABPP using probes with different fluorophores in the same lane to simultaneously profile differences in enzyme activities