Interaction of human mast cell tryptase and chymase with low-molecular-mass serine proteinase inhibitors from the human respiratory tract.
Mast cell degranulation results in the release of serine class proteinases with trypsin- and chymotrypsin-like specificity. While looking for natural protein inhibitors of these enzymes, we studied their reactions with the double-headed Kunitz-type inhibitor, bikunin, and the human bronchial secretion inhibitor (BSI), which are the only known low-molecular-mass proteinase inhibitors of the human respiratory tract. Both trypsin and chymotrypsin can be inhibited by these inhibitors. However, human BSI is unable to inhibit human tryptase and is the physiological counterpart of chymase in the upper respiratory tract. Human bikunin is unable to inhibit human chymase and human tryptase. Furthermore, human tryptase is also not inhibited by a fragment that consists only of the trypsin-specific C-terminal inhibitor domain of human bikunin. This finding contradicts reports that claim the occurrence of a tryptase-specific proteinase inhibitor in rat mast cells.
Hochstrasser
K
K
Department of Otorhinolaryngology, Ludwig Maximilians University, Munich, Federal Republic of Germany.
Gebhard
W
W
Albrecht
G
G
Rasp
G
G
Kastenbauer
E
E
D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry* / Q000166:cytology; D053818:Chymases; D006023:Glycoproteins / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008407:Mast Cells / Q000201:enzymology*; D008562:Membrane Glycoproteins; D008970:Molecular Weight; D014066:Palatine Tonsil / Q000166:cytology / Q000201:enzymology; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D014360:Trypsin Inhibitor, Kunitz Soybean; D053802:Tryptases
D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053491:Proteinase Inhibitory Proteins, Secretory; D011506:Proteins; C109148:SPINT2 protein, human; D015842:Serine Proteinase Inhibitors; D014360:Trypsin Inhibitor, Kunitz Soybean; D012697:Serine Endopeptidases; C083294:chymase 2; D053818:Chymases; C509223:Tpsab1 protein, rat; C509221:Tpsb2 protein, rat; D053802:Tryptases