3,4-Dichloroisocoumarin

3,4-Dichloroisocoumarin (3,4-DCI) is a serine protease inhibitor. 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. It has been used to functionally characterize the catalytic activities of multiple proteases including rat liver MPC and extracellular lipase.

Useful in a rapid staining method for identification of macrophages; counts by this method were confirmed by the more complex morphological criteria, by phagocytosis, and by the presence of Fc receptors. It is an inhibitor of Chymotrypsin and Trypsin. ,4 Dichloroisocoumarin also inhibits granzymes A, B, and H, cathepsin G, neutrophil elastase, proteinase and blocks apoptotic internucleosomal DNA cleavage in thymocytes without the involvement of endonucleases.

ChEBI: 3,4-dichloroisocoumarin is a member of the class of isocoumarins that is isocoumarin substituted by chloro groups at positions 3 and 4. It is a serine protease inhibitor. It has a role as a geroprotector and a serine protease inhibitor. It is a member of isocoumarins and an organochlorine compound.

A potent irreversible inhibitor of serine proteases. Blocks apoptotic internucleosomal DNA cleavage in thymocytes without the involvement of endonucleases. Reacts with serine proteases to release an acylchloride moiety that can acylate another active site residue. Does not affect thiol proteases and metalloproteases. Also has no activity towards β-lactamases. Effective at concentrations ranging from 5-100 μM.

Product does not compete with ATP.

[1] J. WADE HARPER  James C P  Keiji Hemmi. Reaction of serine proteases with substituted isocoumarins: discovery of 3,4-dichloroisocoumarin, a new general mechanism based serine protease inhibitor[J]. Biochemistry Biochemistry, 1985, 24 8: 1831-1841. DOI: 10.1021/bi00329a005
[2] M. PEREIRA. 3,4-dichloroisocoumarin-induced activation of the degradation of beta-casein by the bovine pituitary multicatalytic proteinase complex.[J]. The Journal of Biological Chemistry, 1992, 8 1: 7949-7955. DOI: 10.1016/s0021-9258(18)42604-x
[3] HAKIM DJABALLAH. Use of serine-protease inhibitors as probes for the different proteolytic activities of the rat liver multicatalytic proteinase complex[J]. The FEBS journal, 1992, 209 2: 629-634. DOI: 10.1111/j.1432-1033.1992.tb17329.x
[4] IVANA LEI ALER. Inhibition of extracellular lipase from Streptomyces rimosus with 3,4-dichloroisocoumarin.[J]. Journal of Enzyme Inhibition and Medicinal Chemistry, 2013, 28 5: 1094-1104. DOI: 10.3109/14756366.2012.716834