Effects of lipid-binding proteins apo A-I, apo A-IL, beta 2-glycoprotein I, and C-reactive protein on activation of factor X by tissue factor--factor VIIa

Thromb Res. 1988 Jun 1;50(5):669-78. doi: 10.1016/0049-3848(88)90325-8.


Tissue factor is the membrane-associated protein which mediates activation of factors IX and X by factor VII. In a purified, reconstituted bovine system, factor X activation by the tissue factor-factor VIIa complex is inhibited by the mixed apoproteins from human high density lipoprotein (HDL) and by isolated apolipo-protein A-II (apo A-II). Other proteins found associated with plasma lipoproteins, apolipoprotein A-I (apo A-I), C-reactive protein (CRP), and beta 2-glycoprotein I (beta 2 GPI), have been examined for effects on the activation of factor X by tissue factor-factor VIIa. In these experiments, bovine tissue factor, reconstituted into phosphatidylserine-phosphatidylcholine (PS/PC; 30/70) vesicles, was used at a single concentration while factor X (the substrate), factor VIIa (the enzyme), and the potentially inhibitory proteins were varied in a continuous chromogenic assay. Apo A-II and CRP clearly inhibit tissue factor-factor VIIa activation of factor X, while apo A-I and beta 2 GPI have little or no effect. These results demonstrate that different lipid binding proteins vary in their effects on tissue factor activity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Apolipoprotein A-I
  • Apolipoprotein A-II
  • Apolipoproteins A / blood
  • C-Reactive Protein / metabolism
  • Carrier Proteins / blood*
  • Factor VII / metabolism*
  • Factor VIIa
  • Factor X / metabolism*
  • Glycoproteins / blood
  • Humans
  • Lipids / blood*
  • beta 2-Glycoprotein I


  • Apolipoprotein A-I
  • Apolipoprotein A-II
  • Apolipoproteins A
  • Carrier Proteins
  • Glycoproteins
  • Lipids
  • beta 2-Glycoprotein I
  • Factor VII
  • Factor X
  • C-Reactive Protein
  • Factor VIIa