Used as a reversible inhibitor of serine proteases, particularly trypsin-like enzymes. Commonly employed in biochemical research to prevent protein degradation during cell lysis and protein purification. Frequently added to protease inhibitor cocktails to protect target proteins from enzymatic breakdown. Also utilized in studies involving blood coagulation and fibrinolysis due to its ability to inhibit plasmin and thrombin activity. Its cell-impermeable nature makes it suitable for extracellular enzyme inhibition in cell culture experiments.