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Secretion of extracellular superoxide dismutase in neonatal lungs.
- Source :
-
American journal of physiology. Lung cellular and molecular physiology [Am J Physiol Lung Cell Mol Physiol] 2000 Nov; Vol. 279 (5), pp. L977-84. - Publication Year :
- 2000
-
Abstract
- Extracellular superoxide dismutase (EC-SOD), the only known enzymatic scavenger of extracellular superoxide, may modulate reactions of nitric oxide (NO) in the lungs by preventing reactions between superoxide and NO. The regulation of EC-SOD has not been examined in developing lungs. We hypothesize that EC-SOD plays a pivotal role in the response to increased oxygen tension and NO in the neonatal lung. This study characterizes rabbit EC-SOD and investigates the developmental regulation of EC-SOD activity, protein expression, and localization. Purified rabbit EC-SOD was found to have several unique biochemical attributes distinct from EC-SOD in other species. Rabbit lung EC-SOD contains predominantly uncleaved subunits that do not form disulfide-linked dimers. The lack of intersubunit disulfide bonds may contribute to the decreased heparin affinity and lower EC-SOD content in rabbit lung. EC-SOD activity in rabbit lungs is low before birth and increases soon after gestation. In addition, the enzyme is localized intracellularly in preterm and term rabbit lungs. Secretion of active EC-SOD into the extracellular compartment increases with age. The changes in EC-SOD localization and activity have implications for the neonatal pulmonary response to oxidative stress and the biological activity of NO at birth.
- Subjects :
- Aging
Amino Acid Sequence
Animals
Animals, Newborn
Aorta enzymology
Chromatography, Affinity
Disulfides analysis
Embryonic and Fetal Development
Isoenzymes chemistry
Isoenzymes isolation & purification
Isoenzymes metabolism
Lung embryology
Lung growth & development
Molecular Sequence Data
Peptide Fragments chemistry
Protein Subunits
Rabbits
Superoxide Dismutase chemistry
Superoxide Dismutase isolation & purification
Extracellular Space enzymology
Lung enzymology
Superoxide Dismutase metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1040-0605
- Volume :
- 279
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Lung cellular and molecular physiology
- Publication Type :
- Academic Journal
- Accession number :
- 11053035
- Full Text :
- https://doi.org/10.1152/ajplung.2000.279.5.L977