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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1985-7-24
pubmed:abstractText
Binding of heparin and low molecular weight heparin fragments (CY 222, Mr range 1500-8000) to human vascular endothelial cells was studied. Primary culture of human umbilical vein endothelial cells and either 125I or 3H-labeled heparin or [125I]CY 222 were used. Slow, saturable and specific binding was found. No other tested glycosaminoglycan, excepting a highly sulfated heparan fraction, was able to compete for heparin binding. Two groups of binding sites for [3H]heparin could be distinguished: one with high affinity (Kd = 0.12 microM) and another with lower affinity (Kd = 1.37 microM) and a relative large capacity of binding (1.16 X 10(7) molecules/cell) was calculated. The Kd for unlabeled heparin, as calculated from competition experiments, was 0.23 microM. Much lower affinity was calculated for unlabeled low molecular weight heparin fragments CY 222 (Kd = 4.3 microM) from competition experiments with [125I]CY 222. The binding reversibility was only partial for unfractionated heparin. Even by chasing with unlabeled compound, a fraction of 25-30% was not dissociable from endothelial cells. This fraction was much lower if incubation was carried out at 4 degrees C. The addition of basic proteins (histones) to the incubation medium greatly enhanced the undissociable binding at 37 degrees C, but not at 4 degrees C. The undissociable fraction of heparin was not available to degradation by purified microbial heparinase. These results suggest that a fraction of bound heparin is internalized by the vascular endothelium.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
845
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
196-203
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Binding and endocytosis of heparin by human endothelial cells in culture.
pubmed:publicationType
Journal Article, Comparative Study