(R)-MG132

(R)-MG132 (CAS No.: 1211877-36-9) is a stereoisomeric variant of the widely used proteasome inhibitor MG-132 and is classified within peptide aldehyde–based proteasome modulators commonly employed in ubiquitin–proteasome system research. As the enantiomer of MG-132, (R)-MG132 exhibits markedly reduced biological activity and is generally characterized by minimal or negligible inhibition of the 20S proteasome, in contrast to the potent inhibitory effects associated with the parent compound; accordingly, it demonstrates substantially weaker cytotoxicity in cellular systems. Mechanistically, while MG-132 targets the chymotrypsin-like activity of the 20S proteasome to regulate protein degradation and downstream signaling pathways such as NF-κB and apoptosis, (R)-MG132 is typically regarded as functionally inactive in this context and is widely utilized as a negative control to distinguish on-target proteasome inhibition from off-target or nonspecific effects. Its apparent lack of inhibitory activity places its effective potency outside the typical nanomolar to low micromolar range observed for active proteasome inhibitors. In biomedical research and drug discovery, (R)-MG132 is therefore valuable in experimental designs requiring rigorous validation of proteasome-dependent mechanisms, including studies in cell-based assays and mechanistic investigations, where dosing and application conditions are adapted to the specific experimental framework.