3 4-Dichloroisocoumarin (CAS 51050-59-0) is a chlorinated derivative of isocoumarin that functions as an inhibitor of serine proteases This compound interacts with the active site serine residue of the enzyme thereby suppressing proteolytic activity Serine proteases play essential roles in various physiological processes including digestion immune response and cell signaling pathways 3 4-Dichloroisocoumarin is widely utilized as a biochemical tool for investigating serine protease function and enzymatic mechanisms in molecular and cellular studies