The Activity based protein profiling

About 30% of human proteins have not been characterized yet in terms of activity and substrates, but their incorrect functionality is often one molecular basis for human diseases.
A research group of The Scripps Research Institute tried to overcome this problem and developed a system, usable in high throughput screening, to analyse not well characterized proteins.

Their ABPP (Activity based protein profiling) approach uses a chemical probe enable to fit in catalytic site of a broader range of proteins, belonging to the same family. In this way it is negligible to know all biochemical properties of the specific protein or the ideal substrate for each target. The probe is conjugated to a polarized fluorophore that could monitor the change in the catalytic site conformation in presence of the inhibitor and make possible to use this technique in high throughput screening.
One limitation of this method is the need, at least in high throughput, for purified proteins, otherwise with such a generic substrate it could be difficult to relate results of a screening to a specific protein. In this case it’s crucial to retest positive hits in gel based assays in order to obtain straightforward data. However, ABPP represents also a good starting point for biochemical characterization of unknown proteins.