Linked Life Data

3155968

Source:http://linkedlifedata.com/resource/pubmed/id/3155968

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1985-4-24
pubmed:abstractText
The binding of hematoporphyrin derivative to membrane was studied at the molecular level, employing fluorimetric techniques and using liposomes (large unilamellar) to model biological membranes. Two specific issues were probed: (a) the effect of increasing the porphyrin-liposome incubation period (37 degrees C, neutral pH, in the dark) from 2 h up to 24 h, with liposomes composed of PC or PC/cholesterol 7:3 (molar ratio); (b) the effects of membrane lipid composition, in terms of mol% cholesterol in PC/cholesterol liposomes, on the porphyrin-membrane binding equilibrium, for a long incubation period (16 h). The data were processed and found to be in good agreement with the following proposed model: With time (t greater than 2 h), the porphyrin fractions into three components, two of them binding to membrane with high and low affinities, respectively, the time effect reaching a plateau at 16 h. Linkage was observed between the slow process and changes in the available pools of each fraction. At sufficiently long incubations, the magnitude of each of the two binding fractions was found to be (roughly) 30%, independent of the membrane lipid composition. On the other hand, the magnitude of the binding constants was found to depend on the lipid composition, that of the high-affinity fraction decreasing from 9000 M-1 for 0% cholesterol, to 3000 M-1 for 40% cholesterol, then increasing back to 5000 M-1 upon further increase in cholesterol (to 50% mol) and that of the low-affinity fraction going from 1000 M-1, to 100 M-1, to 300 M-1 for similar lipid compositions. The origin of the time effect, in terms of porphyrin-specific processes, and the biological relevance of the present findings are discussed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
813
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
307-12
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Binding of hematoporphyrin derivative to membranes. Expression of porphyrin heterogeneity and effects of cholesterol studied in large unilamellar liposomes.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.