Antithrombin-mediated inhibition of factor VIIa-tissue factor complex by the synthetic pentasaccharide representing the heparin binding site to antithrombin

Thromb Haemost. 1996 Jul;76(1):5-8.


We examined the effect of the synthetic pentasaccharide representing the minimal binding site of heparin to antithrombin on the antithrombin-mediated inactivation of factor VIIa bound to tissue factor. This effect was compared to the effect of unfractionated heparin. Using purified recombinant human coagulation factors and either a clotting or an amidolytic assay for the determination of the residual activity of factor VIIa, we showed that the pentasaccharide was an efficient antithrombin-dependent inhibitor of the coagulant activity of tissue factor-factor VIIa complex. In our experimental conditions, assuming a mean MW of 14,000 for heparin, the molar pseudo-first order rate constants for ATIII-mediated FVIIa inhibition by ATIII-binding heparin and by the synthetic pentasaccharide were found to be similar with respective values of 104,000 +/- 10,500 min-1 and 112,000 +/- 12,000 min-1 (mean +/- s.e.m., n = 3).

MeSH terms

  • Antithrombin III / metabolism*
  • Binding Sites
  • Factor VII / antagonists & inhibitors*
  • Factor VII / metabolism
  • Factor VIIa / antagonists & inhibitors*
  • Factor VIIa / metabolism
  • Fibrinolytic Agents / pharmacology*
  • Heparin / metabolism*
  • Humans
  • Oligosaccharides / pharmacology*
  • Thromboplastin / antagonists & inhibitors*
  • Thromboplastin / metabolism


  • Fibrinolytic Agents
  • Oligosaccharides
  • Antithrombin III
  • Factor VII
  • Heparin
  • Thromboplastin
  • Factor VIIa