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SP-A binds alpha1-antitrypsin in vitro and reduces the association rate constant for neutrophil elastase
- Source :
- Respiratory Research, Vol 6, Iss 1, p 146 (2005)
- Publication Year :
- 2005
- Publisher :
- BMC, 2005.
-
Abstract
- Abstract Background α1-antitrypsin and surfactant protein-A (SP-A) are major lung defense proteins. With the hypothesis that SP-A could bind α1-antitrypsin, we designed a series of in vitro experiments aimed at investigating the nature and consequences of such an interaction. Methods and results At an α1-antitrypsin:SP-A molar ratio of 1:1, the interaction resulted in a calcium-dependent decrease of 84.6% in the association rate constant of α1-antitrypsin for neutrophil elastase. The findings were similar when SP-A was coupled with the Z variant of α1-antitrypsin. The carbohydrate recognition domain of SP-A appeared to be a major determinant of the interaction, by recognizing α1-antitrypsin carbohydrate chains. However, binding of SP-A carbohydrate chains to the α1-antitrypsin amino acid backbone and interaction between carbohydrates of both proteins are also possible. Gel filtration chromatography and turnover per inactivation experiments indicated that one part of SP-A binds several molar parts of α1-antitrypsin. Conclusion We conclude that the binding of SP-A to α1-antitrypsin results in a decrease of the inhibition of neutrophil elastase. This interaction could have potential implications in the physiologic regulation of α1-antitrypsin activity, in the pathogenesis of pulmonary emphysema, and in the defense against infectious agents.
- Subjects :
- Diseases of the respiratory system
RC705-779
Subjects
Details
- Language :
- English
- ISSN :
- 14659921
- Volume :
- 6
- Issue :
- 1
- Database :
- Directory of Open Access Journals
- Journal :
- Respiratory Research
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.9fd609ef139c4d479a0c8cceac82fec9
- Document Type :
- article
- Full Text :
- https://doi.org/10.1186/1465-9921-6-146