Description
An inhibitor of the ubiquitin-proteasome system; increases the levels of polyubiquitinated proteins in HeLa cells, but does not inhibit the chymotrypsin-like, trypsin-like, or peptidylglutamyl peptide hydrolyzing-like activities of the 20S proteasome, in cell-free assays at 10 µM; decreases the viability of HeLa cells (IC50 = 2 µM)