The influence of beta2-glycoprotein I on tissue factor activity.
The beta2-glycoprotein I (beta2-GPI) is known for its procoagulant as well as anticoagulant properties. The influence of beta2-GPI on tissue factor (TF) activity was investigated by chromogenic assays for both factor Xa generation and factor VIIa activity. When 1.36 mg/mL beta2-GPI was added to phospholipids prior to the addition of TF and factor VIIa, the TF activity was moderately inhibited by beta2-GPI in a concentration-dependent manner. Inhibition of TF activity by beta2-GPI required incubation for at least 20 min. When beta2-GPI was added to the mixture of phospholipids and TF followed by the addition of factor VIIa, the TF activity was little affected by the addition of beta2-GPI. The TF activity was inhibited when beta2-GPI was added after forming a complex with TF and factor VIIa. The results suggest that beta2-GPI inhibits both the reconstitution of TF with phospholipids and factor Xa generation by the TF factor-VIIa complex but does not affect the formation of a TF factor-VIIa complex.
Department of Internal Medicine, Health Science University of Hokkaido, Ishikari-Toubetsu, Japan.
M
M
Ieko
T
T
Yasukouchi
K I
KI
Sawada
T
T
Koike
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015942:Factor VIIa / Q000187:drug effects / Q000378:metabolism*; D015951:Factor Xa / Q000187:drug effects / Q000378:metabolism*; D006023:Glycoproteins / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D013925:Thromboplastin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D053482:beta 2-Glycoprotein I
D000925:Anticoagulants; D006023:Glycoproteins; D053482:beta 2-Glycoprotein I; D013925:Thromboplastin; D015942:Factor VIIa; D015951:Factor Xa