p-APMSF has been shown to be an irreversible and specific inhibitor of the class of plasma serine proteases which display substrate specificity for positively charged side chains of arginine and lysine amino acids. In addition, p-APMSF has been noted to be a protease inhibitor that blocks intracellular acidification, DNA fragmentation, and 5-Fluoro-2'-deoxyuridine induced cell death in mouse mammary tumor cells. This compound also demonstrates inhibitory abilities toward esterase activity in thrombin like enzymes. p-APMSF, Hydrochloride is an inhibitor of KLK11, Thrombin, Trypsin, C1r, C1s, Factor X and plasminogen.