Proteasome Inhibitor II is a potent, cell-permeable, reversible proteasome inhibitor. The compound has been shown to inhibit chymotrypsin-like activity of the pituitary multicatalytic proteinase complex (MPC; Ki = 460 nM). Proteasome Inhibitor II blocks the decay of IkB-a and IkB-b proteins in exponentially growing WEHI 231 cells. The chemical has been shown not to inhibit the peptidyl-glutamyl peptide hydrolyzing activity of MPC at concentrations as high as 200 µM.
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