Linked Life Data

3955055

Source:http://linkedlifedata.com/resource/pubmed/id/3955055

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1986-5-2
pubmed:abstractText
The central enzyme involved in blood coagulation and activation of platelets is the serine proteinase thrombin. The principal inhibitor of this proteinase in plasma is antithrombin. The mechanism of regulation of the thrombin-antithrombin reaction remains unknown. Two polypeptides of 74 and 55 kDa present on the platelet surface and in plasma are known to specifically enhance the activity of thrombin on different substrates. This study was undertaken to assess the effects of these platelet proteins on thrombin-antithrombin interaction. Direct measurements of residual thrombin activity in mixtures of thrombin and antithrombin, in the presence or absence of the platelet proteins, were made utilizing a specific chromogenic substrate. Under these conditions, when 60% of thrombin activity was inhibited by antithrombin in controls, 100% of enzyme activity was retained in the presence of the platelet proteins. When heparin was used in these assays, the rate of inhibition of thrombin by antithrombin was much more rapid and 62% of thrombin activity remained after 1 min. Under these conditions, the platelet proteins continued to protect thrombin from inactivation with 98% activity remaining at 1 min and 85% activity at 5 min. In contrast, the inhibition of trypsin by antithrombin was not affected by the platelet proteins. Additional studies in platelet aggregation showed that the platelet polypeptides have two effects on thrombin: (i) protection of the enzyme inhibition by antithrombin and (ii) stabilization of thrombin from loss of activity due to aging. The results suggest a novel role for the platelet proteins in hemostasis - regulation of the inhibition of thrombin by antithrombin.
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
28
pubmed:volume
870
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
204-10
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Thrombin-reactive polypeptides of platelets may regulate inhibition of thrombin by antithrombin.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.