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Blood Coagulation

Authors
  • Butenas, S.1
  • Mann, K. G.
  • Butenas,1
  • 1 University of Vermont, Department of Biochemistry, Burlington, VT, 05405 0068, USA , Burlington
Type
Published Article
Journal
Biochemistry (Moscow)
Publisher
Pleiades Publishing
Publication Date
Jan 01, 2002
Volume
67
Issue
1
Pages
3–12
Identifiers
DOI: 10.1023/A:1013985911759
Source
Springer Nature
Keywords
License
Yellow

Abstract

The process of tissue factor initiated blood coagulation is discussed. Reactions of the blood coagulation cascade are propagated by complex enzymes containing a vitamin K-dependent serine protease and an accessory cofactor protein that are assembled on a membrane surface in a calcium-dependent manner.These complexes are 105 109-fold more efficient in proteolyses of their natural substrates than enzymes alone. Based upon data acquired using several in vitro models of blood coagulation, tissue factor initiated thrombin generation can be divided into two phases: an initiation phase and a propagation phase. The initiation phase is characterized by the generation of nanomolar amounts of thrombin, femto- to picomolar amounts of factors VIIa, IXa, Xa, and XIa, partial activation of platelets, and almost quantitative activation of procofactors, factors V and VIII. The duration of this phase is primarily influenced by concentrations of tissue factor and TFPI. The characteristic features of the propagation phase are: almost quantitative prothrombin activation at a high rate, completion of platelet activation, and solid clot formation. This phase is primarily regulated by antithrombin III and the protein C system. Thrombin generation during the propagation phase is remarkably suppressed in the absence of factor VIII and IX (hemophilia A and B, respectively) and at platelet counts <5% of mean plasma concentration. The majority of data accumulated in in vitro models and discussed in this review are in good agreement with the results of in vivo observations.

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