FMK-MEA is widely used in biochemical research as a potent and irreversible inhibitor of cysteine proteases. Its primary application lies in studying the role of these enzymes in various biological processes, such as apoptosis, immune response, and protein degradation. Researchers utilize FMK-MEA to selectively block protease activity, enabling the investigation of enzyme function in cellular pathways and disease mechanisms, particularly in cancer and neurodegenerative disorders. Additionally, it serves as a valuable tool in drug discovery for identifying and validating protease targets. Its cell-permeable nature allows for effective use in both in vitro and in vivo studies, making it a versatile reagent in proteomics and enzymology research.