Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.6 (thromboplastin)
 13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The binding ability of low molecular weight heparin (FR-860), and conventional unfractionated heparin (UF-heparin) to factor Xa (F.Xa), thrombin and AT III was investigated using FR-860- and UF-heparin-Sepharoses. FR-860 could not bind directly to F.Xa. FR-860 bound to thrombin and AT III with stronger affinity to AT III than to thrombin. On the other hand, UF-heparin bound to F.Xa, thrombin and AT III with the strongest affinity to AT III followed by thrombin and F.Xa. AT III mediated the binding between F.Xa and FR-860 and accelerated the reaction between F.Xa and UF-heparin. On the other hand, AT III did not affect the binding between thrombin and FR-860 or UF-heparin. Diisopropyl fluorophosphate-treated thrombin inhibited the binding between AT III and FR-860, but not that between AT III and UF-heparin. These results suggest that the anti-F.Xa activity of FR-860 is mediated by AT III. Furthermore, the difference of antithrombin activity between FR-860 and UF-heparin depends on the capability to form ternary complex of FR-860 or UF-heparin, AT III and thrombin.
 ...
PMID:Study of anticoagulant mechanism of low molecular weight heparin. 132 95

1. A procoagulant protein was isolated from Vipera aspis aspis (Aspic viper) venom by Sephadex G-75, DEAE-Sephacel, Q-Sepharose and Sephadex G-150 column chromatography. 2. The purified protein has a molecular weight of 125,000 and an isoelectric point of 4.3. 3. This procoagulant decreased the clotting time of plasma from humans, however, direct fibrongen clotting activity was not detected. 4. Diisopropyl fluorophosphate, a serine-protease inhibitor affected coagulant activity of purified protein significantly, while a factor Xa inhibitor (3-ABPE) possessed a slight inhibitory effect. 5. Bovine prothrombin incubated with isolated protein, phospholipid emulsion, bovine factor V and calcium ions drastically decreased the clotting time of fibrinogen and expressed hydrolytic activity against synthetic arginine esterase substrates. However, no hydrolytic activity these substrates was detected with the procoagulant alone indicating that this protein might participate in activation of prothrombin.
 ...
PMID:Isolation and characterization of procoagulant from the venom of Vipera aspis aspis. 834 17