Linked Life Data

7640284

Source:http://linkedlifedata.com/resource/pubmed/id/7640284

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
32
pubmed:dateCreated
1995-9-19
pubmed:abstractText
Spread monolayers of pulmonary surfactant protein SP-A, alone or mixed with phospholipid(s), were formed at the air-water interface. Binary monolayers of SP-A plus dipalmitoylphosphatidylcholine (DPPC) showed positive deviations from ideal behavior of the mean areas in the films consistent with partial miscibility and interaction between the protein and lipid. During compression of SP-A/DPPC films which contained > or = 5 wt % SP-A, properties were displayed which were consistent with the protein being partially squeezed out at surface pressures of about 30 mN/m. Some protein appeared to remain in the monolayers even when they were compressed to high surface pressures of about 65-70 mN/m, and it was possibly included in the collapse phase(s) that was (were) formed at 72 mN/m. During dynamic cyclic compression-expansion of SP-A/DPPC monolayers initially formed at low surface pressures, SP-A enhanced the respreading of the films compressed beyond collapse compared to the respreading after collapse of films containing DPPC alone. Spread monolayers of SP-A plus either dipalmitoylphosphatidylglycerol (DPPG) or a mixture of DPPC plus DPPG (7:3, mol/mol) displayed additivity of the mean areas in the films, consistent with complete immiscibility (or ideal miscibility, an unlikely effect) between the protein and lipid components. Electrostatic repulsion between SP-A and DPPG, both negatively charged at physiological pH, possibly governed the behavior of these lipid-protein films. Calcium ions in the subphase did not alter the properties of SP-A/DPPC films, whereas they improved the ability of SP-A to mix with DPPG and DPPC/DPPG. Binding of calcium to the negatively charged DPPG and SP-A may account for association of the protein with DPPG and DPPC/DPPG in the monolayers in the presence of the divalent ions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10279-89
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Pulmonary surfactant protein SP-A with phospholipids in spread monolayers at the air-water interface.
pubmed:affiliation
Department of Biochemistry, Memorial University of Newfoundland, St. John's, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't