Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1994-5-26
pubmed:abstractText
The structural and functional integrity of pulmonary surfactant depends on several specific proteins. Two of these, SP-A and SP-D, are large and water-soluble, while SP-B and SP-C are small and very hydrophobic. SP-A is an 18-mer of 26 kDa polypeptide chains and contains N-linked oligosaccharides. Structurally, it can be characterized as a collagen/lectin hybrid. Together with SP-B, SP-A is required for conversion of secreted endogenous surfactant to tubular myelin in the alveolar lining. It also regulates surfactant secretion and reuptake of surfactant lipids by type II cells; these functions are probably receptor mediated. SP-D, a 12-mer of 39 kDa polypeptide chains, is a collagenous glycoprotein with structural similarities to C-type lectins. Both SP-A and SP-D stimulate alveolar macrophages. SP-B is a 79-residue polypeptide that contains three intrachain disulphide bridges. It exists mainly as a homodimer, which is strongly positively charged and may selectively remove anionic and unsaturated lipid species from the alveolar surface film, thereby increasing surface pressure. SP-C is a mainly alpha-helical, extraordinarily hydrophobic polypeptide containing 35 amino acid residues and covalently linked palmitoyl groups. Its alpha-helical portion is inserted into surfactant lipid bilayers. SP-C accelerates the adsorption of lipid bilayers to an interfacial monolayer. In babies with respiratory distress syndrome, the clinical response to treatment with surfactant containing SP-B and SP-C is much faster than in babies treated with protein-free synthetic surfactant. We speculate that, in the near future, surfactant preparations based on recombinant hydrophobic proteins will be available for clinical use.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0903-1936
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
372-91
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
The proteins of the surfactant system.
pubmed:affiliation
Dept of Chemistry 1, Karolinska Institutet, Stockholm, Sweden.
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't