CA-074 Methyl Ester is widely used in biomedical research as a selective inhibitor of cathepsin B, a lysosomal cysteine protease involved in protein degradation. Its primary application lies in studying the role of cathepsin B in various pathological processes, including cancer, neurodegenerative diseases, and inflammation. Researchers use this compound to probe the enzyme's contribution to tumor invasion and metastasis, as elevated cathepsin B activity is often associated with aggressive cancer phenotypes. It is also employed in models of ischemic brain injury and Alzheimer’s disease to assess the impact of cathepsin B inhibition on neuronal damage and amyloid processing. Due to its cell permeability, the methyl ester form allows effective intracellular delivery, making it a valuable tool in cellular and animal studies aimed at understanding protease function and developing targeted therapies.