3,4-Dichloroisocoumarin

3,4-Dichloroisocoumarin (3,4-DCI) is a serine protease inhibitor.{38255} It completely inhibits enzyme activity of 24 serine proteases including human leukocyte elastase, thrombin, plasmin, Factor Xa, and Factor XIIa in vitro. 3,4-DCI stimulates caseinolytic activity of bovine pituitary multicatalytic proteinase complex (MPC) by inducing a conformational change in the MPC that exposes the caseinolytic active site.{38256} It has been used to functionally characterize the catalytic activities of multiple proteases including rat liver MPC and extracellular lipase.{38257,38258}