Epoxomicin is a naturally occurring proteasome inhibitor with high selectivity for the 20S proteasome complex. Its primary application lies in research settings, particularly in the study of protein degradation pathways and cellular regulation. Due to its ability to specifically inhibit the chymotrypsin-like activity of the proteasome, it is widely used to investigate the role of proteasomal degradation in processes such as apoptosis, cell cycle progression, and inflammation. It serves as a valuable tool in cancer research, where proteasome inhibition can lead to accumulation of misfolded proteins and subsequent death of malignant cells. Epoxomicin has also been used in the development and validation of other proteasome inhibitors, including clinical agents like bortezomib. Additionally, it has been employed in biochemical assays to probe proteasome function and to study neurodegenerative diseases linked to protein aggregation. Its specificity and potency make it a preferred choice for mechanistic studies in molecular and cellular biology.