The isopropyl group in omuralide is
essential for activity, as is the chloro substituent in salinosporamide
A. Salinosporamide A interacts with the 20S
proteasome by forming a covalent link with the chymotryptic-like
threonine hydroxyl; the X-ray of the bound molecule was published in 2006.This molecule is being developed
by Nereus Pharmaceuticals and currently is in phase I clinical
trials against refractory lymphomas and myelomas, as well
as various solid tumors