Inhibition of human leukocyte elastase, cathepsin G, chymotrypsin A alpha, and porcine pancreatic elastase with substituted isobenzofuranones and benzopyrandiones.
Several 3-halo-3-(1-haloalkyl)-1(3H)-isobenzofuranones, 3-(1-haloalkylidene)-1(3H)-isobenzofuranones, and 3-bromomethyl-1H-2-benzopyran-1-ones containing masked halo ketone functional groups were synthesized and tested as inhibitors of several serine proteases including human leukocyte (HL) elastase and cathepsin G. While many of the 3-halo-3-(1-haloalkyl)-1(3H)-isobenzofuranones were quite potent inhibitors of the enzymes tested, the alkylideneisobenzofuranones and benzopyran-1-ones inhibited poorly or not at all. The 3-halo-3-(1-haloalkyl)-1(3H)-isobenzofuranones decomposed rapidly upon addition to buffer to give the corresponding 3-alkyl-1H-2-benzopyran-1,4(3H)-diones. The pure benzopyran-1,4-diones were extremely potent inhibitors of HL elastase and chymotrypsin A alpha but did not inactivate porcine pancreatic elastase or cathepsin G. Enzymes inhibited by the isobenzofuranones and benzopyran-1,4-diones regained activity slowly upon standing or after dialysis (t1/2 = 5-16 h) and more rapidly in the presence of 0.5 M hydroxylamine, which indicated the presence of labile acyl moieties in the inhibited enzyme. These results are consistent with a scheme in which the active site serine of the protease reacts with the lactone carbonyl of these inhibitors to give a stable acyl enzyme and alkylation of another active site residue by the unmasked halo ketone functional group does not occur.
D000818:Animals; D001572:Benzofurans / Q000138:chemical synthesis / Q000494:pharmacology*; D001578:Benzopyrans / Q000138:chemical synthesis / Q000494:pharmacology*; D056649:Cathepsin G; D002403:Cathepsins / Q000037:antagonists & inhibitors*; D002918:Chymotrypsin / Q000037:antagonists & inhibitors*; D006801:Humans; D007202:Indicators and Reagents; D007700:Kinetics; D007962:Leukocytes / Q000201:enzymology*; D010179:Pancreas / Q000201:enzymology; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors* / Q000097:blood; D012697:Serine Endopeptidases; D013329:Structure-Activity Relationship; D013552:Swine
D001572:Benzofurans; D001578:Benzopyrans; D007202:Indicators and Reagents; D002403:Cathepsins; D012697:Serine Endopeptidases; D002918:Chymotrypsin; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase