Potent, reversible, and cell-permeable proteasome inhibitor (K
i = 4 nM).Reduces the degradation of ubiquitin-conjugated proteins in mammalian cells and permeable stains of yeast by the 26S complex without affecting its ATPase or isopeptidase activities. Activates c-Jun N-terminal kinase (JNK1) which initiates apoptosis. Inhibits NF-κBactivation (IC
50 = 3 μM). This material is ≥95% pure by HPLC. A material with ≥98% purity by HPLC (Cat. No.
474791) and the solid form of this compound (Cat. No.
474787) are also available.