BAY-805

BAY-805 is an inhibitor of ubiquitin-specific protease 21 (USP21; IC₅₀ = 6 nM in a homogenous time-resolved fluorescence (HTRF) assay).¹ It is selective for USP21 over a panel of 44 deubiquitinases (DUBs) and 68 other enzymes, receptors, transporters, and ion channels at 10 µM but does inhibit acetylcholinesterase (AChE) and adenosine transporters by 72 and 62%, respectively. BAY-805 is also selective for USP21 over a panel of six cysteine proteases (IC₅₀s = >20 µM for all) and a panel of greater than 360 kinases at 10 µM but does inhibit MAPK-activated protein kinase 5 (MAPKAPK5), also known as p38-regulated/activated protein kinase (PRAK; IC₅₀ = 8.6 µM). It induces activation of NF-κB in a reporter assay using HEK293T cells (EC₅₀ = 17 nM). BAY-805 reduces spheroid formation in HCT-15 and HT-29 colon cancer cells (IC₅₀s = 1.6 and 7.5 µM, respectively).² In vivo, BAY-805 (5 and 10 mg/kg) decreases disease severity and spleen, liver, kidney, and lung viral titers in a mouse model of enterovirus 71 (EV71) infection.³

WARNING This product is not for human or veterinary use.

1. Göricke, F., Vu, V., Smith, L., et al. Discovery and characterization of BAY-805, a potent and selective inhibitor of ubiquitin-specific protease USP21. J. Med. Chem. 66(5), 3431-3447 (2023).

2. Shin, J.H., Kim, M.-J., Kim, J.Y., et al. USP21-EGFR signaling axis is functionally implicated in metastatic colorectal cancer. Cell Death Discov. 10(1), 492 (2024).

3. Yang, X., Tang, M., Zang, L., et al. Ubiquitin-specific protease 21 aggravates enterovirus 71 (EV71) infection by restricting Lys48-linked ubiquitination of EV71-2A protease. Int. J. Biol. Macromol. 314, 144202 (2025).