Phenylmethanesulfonyl fluoride is widely used as a serine protease inhibitor in biochemical research. It effectively blocks the activity of enzymes like trypsin, chymotrypsin, and thrombin, making it valuable in studying protein function and enzyme mechanisms. In molecular biology, it is employed to prevent protein degradation during cell lysis and protein extraction processes. Additionally, it plays a role in the preparation of samples for electrophoresis and chromatography by maintaining protein integrity. Its application extends to pharmaceutical research, where it aids in the development of enzyme-targeted drugs.