(R)-MG-132 ((S,R,S)-(-)-MG-132) is the enantiomer of MG-132. (R)-MG-132 is a proteasome inhibitor with weaker cell cytotoxicity than MG-132.IC50 & Target:ProteasomeIn Vitro:(R)-MG-132, the stereoisomer of MG-132, is studied as a potential inhibitor of chymotrypsin-like, trypsin-like, and peptidylglutamyl peptide hydrolyzing activities of proteasome.
MG-132 and (R)-MG-132 are investigated for inhibition of ChTL, trypsin-like (TL) and peptidylglutamyl peptide hydrolyzing (PGPH) activities of purified 20S proteasomes isolated from human erythrocytes. For MG-132, the IC50s of 0.89 μM, 104.43 μM, and 5.7 μM for ChTL, TL, and PGPH, respectively. For (R)-MG-132, the IC50s of 0.22 μM, 34.4 μM, and 2.95 μM for ChTL, TL, and PGPH, respectively.