Purification and characterization of a novel Kazal-type serine proteinase inhibitor of neutrophil elastase from sheep lung.
Biochim Biophys Acta
; 1342(1): 51-61, 1997 Sep 26.
Article
in En
| MEDLINE
| ID: mdl-9366270
ABSTRACT
A Kazal-type elastase inhibitor was purified by trichloroacetic acid precipitation of sheep lung lavage fluid followed by chymotrypsin affinity and gel-filtration chromatography of the supernatant. Sheep lung elastase inhibitor (SLEI) is glycosylated. Laser desorption mass spectrometry indicated that SLEI has a molecular mass of 16.8-17.3 kDa. Partial protein sequence of SLEI and of a peptide derived from SLEI showed 31-52% and 51-66% homology at the N-terminus and at the inhibitory site respectively with Kazal-type double-headed proteinase inhibitors (bikazins). SLEI inhibited human leukocyte elastase and porcine pancreatic elastase but not human cathepsin G. It was inactivated by chloramine-T and reactivated when incubated with methionine sulfoxide peptide reductase and dithiothreitol, indicating the presence of a methionine at the active site. The concentration of SLEI in bronchoalveolar lavage fluid (BALF) and lung lymph was 0.28 microM (0.23-0.49); 0.24 microM (0.20-0.31) (median, (range), n = 5), respectively and was undetectable in plasma (< 0.03 microM) suggesting that SLEI is produced in the lung. The median molar ratios of SLEI to alpha1-proteinase inhibitor in BALF and lung lymph were 3.2 to 1 and 0.017 to 1, respectively. These results indicate that SLEI probably makes an important contribution to antielastase defence in epithelial lining liquid.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Serine Proteinase Inhibitors
/
Trypsin Inhibitor, Kazal Pancreatic
/
Leukocyte Elastase
/
Lung
Limits:
Animals
/
Humans
Language:
En
Journal:
Biochim Biophys Acta
Year:
1997
Document type:
Article
Affiliation country:
United kingdom