title: Characterization of a low molecular weight anti-elastase isolated from human bronchial secretion.
abstract: An elastase-specific, low molecular weight inhibitor was isolated from human bronchial secretions that is able to inhibit porcine pancreatic elastase and human granulocyte elastase (Ki = 1.0 X 10(-9) M) but not bovine pancreatic trypsin or human cathepsin G. Under dissociating conditions the inhibitor has a molecular weight of 5000, whereas 10,000 mol. wt. was found for the native protein. The inhibitor was quantified by an enzyme-linked immunosorbent assay using an antiserum prepared in rabbits. In 16 acid-treated sputum samples, the inhibitor was present at concentrations of 1.8 +/- 1.2 microgram/ml (means +/- SD), whereas only trace amounts were detectable in serum. These quantitative results suggest a local production of the inhibitor in the lung.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001980:Bronchi / Q000378:metabolism*; D056649:Cathepsin G; D002403:Cathepsins / Q000037:antagonists & inhibitors; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D005779:Immunodiffusion; D008970:Molecular Weight; D010179:Pancreas / Q000201:enzymology; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D011817:Rabbits; D012697:Serine Endopeptidases; D013552:Swine; D014357:Trypsin / Q000378:metabolism
chemical_list: D000596:Amino Acids; D004791:Enzyme Inhibitors; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D014357:Trypsin