PR 619 is a broad spectrum, reversible inhibitor of the deubiquitinylating enzymes (DUBs) with an EC50 of 1-20 µM in a cell-free assay and only limited activity against other proteases. PR 619 induces accumulation of polyubiquitinated proteins, but has no direct inhibitory effect on the proteasome. PR 619 is cytotoxic in HEK293T and colorectal cancer cells and stabilizes microtubule networks in oligodendroglial cells.
