PS-341 is a specific, reversible and cell permeable dipeptide boronic acid inhibitor of the chymotrypsin-like activity of the proteasome (Ki=0.6nM). It inhibits proliferation of various tumor cell lines with nanomolar potency. Its commercial version was approved by the USFDA for the treatment of relapsed multiple myeloma. The typical concentrations for cell culture use are 1-20 µM. For in vitro use, the typical concentrations are 10-100 µM.
