Lactacystin is a microbial metabolite isolated from Streptomyces that is now widely used as a selective inhibitor of the 20S proteasome. Clasto-lactacystin beta-lactone was later identified as the active metabolite of lactacystin, resulting from the elimination of cysteine and the formation of a reactive...

White to off-white solid. Soluble in DMSO or acetonitrile. Undergoes hydrolysis in aqueous buffers. Potent and selective irreversible and cell permeable proteasome inhibitor. Inhibits the chymotrypsin-like, trypsin-like and caspase-like peptidase activity of the proteasome, The active metabolite of lactacystin...