Ixazomib Citrate (MLN9708) is a prodrug of Ixazomib (MLN2238), which is a selective, orally bioavailable inhibitor of 20S proteasome that inhibits the chymotrypsin-like proteolytic (β5) site with IC50 of 3.4 nM and Ki of 0.93 nM, respectively. Ixazomib (MLN2238) also inhibits caspase-like (β1) and trypsin-like (β2) proteolytic sites with IC50 of 31 nM and 3500 nM, respectively.