BAY-805 Chemical probe for USP21

The probe and control may be requested here.


Bayer in collaboration with the SGC has developed a first-in-class chemical probe BAY-805 for USP21. BAY-805 inhibits USP21 with IC50 < 10 nM in HTRF and Ub-Rhodamine assays. BAY-728 is a closely related negative control with IC50 > 12 micromolar.


BAY-805 is selective for USP21 in a Ub-Rhodamine assay.

selectivity profile
in vitro potency
cell based assay data

BAY-805 binds USP21 in a HiBiT based target engagement assay with an EC50 = 95 nM.


1. Discovery and Characterization of BAY-805, a Potent and Selective Inhibitor of Ubiquitin-Specific Protease USP21. Fabian Göricke, Victoria Vu, Leanna Smith, Ulrike Scheib, Raphael Böhm, Namik Akkilic, Gerd Wohlfahrt, Jörg Weiske, Ulf Bömer, Krzysztof Brzezinka, Niels Lindner, Philip Lienau, Stefan Gradl, Hartmut Beck, Peter J. Brown, Vijayaratnam Santhakumar, Masoud Vedadi, Dalia Barsyte-Lovejoy, Cheryl H. Arrowsmith, Norbert Schmees, and Kirstin Petersen.

pk properties
co-crystal structures
synthetic schemes
materials and methods