Used as an irreversible serine protease inhibitor in biochemical research, particularly to inactivate enzymes during protein extraction and purification. It effectively blocks proteolytic activity, helping preserve sample integrity in cell lysis and tissue homogenization. Commonly applied in studies involving enzyme mechanisms, signal transduction, and apoptosis. Also utilized in proteomics to prevent protein degradation when analyzing labile phosphorylated or acetylated proteins. Its cell-permeable nature allows use in both in vitro and cellular assays, though it requires careful handling due to reactivity and potential toxicity.