Linked Life Data

2144524

Source:http://linkedlifedata.com/resource/pubmed/id/2144524

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
1990-10-18
pubmed:abstractText
The anticoagulant vitamin K-dependent protein S interacts with the complement regulatory protein C4b-binding protein (C4BP), both in purified systems and in plasma. The concentrations of these proteins in plasma are approximately equimolar (0.3 microM) and 30-40% of protein S in plasma is found in the noncomplexed state. Only the uncomplexed form of protein S displays anticoagulant activity and studies have shown that patients with a selective deficiency of free protein S have a high incidence of thrombosis. In this study, we report that the protein S-C4BP interaction is at least 100-fold tighter in the presence of Ca2+ than in EDTA. The KD in the presence of Ca2+ was estimated with a gel filtration technique to be less than 5 x 10(-10) M, whereas in the presence of EDTA, it was approximately 100-fold higher. Ca2+ titration experiments suggested that the Ca2+ sites which function in the protein S-C4BP interaction are of high affinity which, in turn, suggests that they may be independent of the gamma-carboxyglutamic acid region and may be present in the epidermal growth factor-like domains of protein S. The high affinity of the protein S-C4BP interaction in the presence of Ca2+ suggested that virtually all of the protein S in whole blood should be complexed with C4BP. However, even though the protein S-C4BP interaction in Ca2(+)-containing serum was shown to have the same high affinity as in purified systems, approximately 30-40% of the protein S in serum was free. These results appear best explained by the presence of a third component in whole blood which regulates the protein S-C4BP interaction, keeping approximately 30-40% of circulating protein S in its free, functionally anticoagulant form. It is speculated that persons with little free protein S may be deficient in this hypothetical third component.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16082-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
High affinity interaction between C4b-binding protein and vitamin K-dependent protein S in the presence of calcium. Suggestion of a third component in blood regulating the interaction.
pubmed:affiliation
Department of Clinical Chemistry, University of Lund, Malmö General Hospital, Sweden.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't