A cell-permeable inhibitor of the ubiquitin-specific protease (IC₅₀ = 8.6 µM) and the closely related deubiquitinase (DUB) USP47. P22077 displays weak or no inhibition (EC₅₀>50 µM) towards a panel of 14 isopeptidases and other proteases. Inhibits USP7-mediated p53 deubiquitination.