PMSF is widely used as a serine protease inhibitor in biochemical research. It is commonly added to cell lysis buffers to prevent protein degradation during the extraction process, ensuring the integrity of proteins for analysis. In molecular biology, PMSF is employed to inhibit proteases that may interfere with experiments involving DNA, RNA, or protein isolation. It is also utilized in the study of enzyme mechanisms, particularly for serine proteases like trypsin and chymotrypsin, to block their activity. Additionally, PMSF is applied in the preparation of samples for techniques such as Western blotting and chromatography to maintain protein stability. Its rapid action and effectiveness make it a valuable tool in laboratory settings, though it requires careful handling due to its toxicity.