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)

Effects of human placental calphobindin II (CPB-II) on the protein C activation and prothrombin activation on the cell surface of cultured calf pulmonary arterial endothelial cells have been investigated. CPB-II inhibited thrombin generation by factor Xa bound to the surface of the cultured endothelial cells in a dose-dependent manner. The amount (IC50) of CPB-II causing the inhibition at 50% was estimated to be approximately 10 nM. CPB-II was found to be ineffective, however, in the protein C activation by thrombin-thrombomodulin (TM) complex on the cell surface. Assay using purified TM revealed that CPB-II was able to exhibit the inhibitory potency for the protein C activation exclusively in the reconstituted system with negatively charged phospholipids. These results suggest that the neutral phospholipids participate in the protein C activation through the thrombin-TM system on the endothelial cell surface. The ability of CPB-II to inhibit procoagulant activity without affecting anticoagulant activity on the cultured endothelial cells is probably related to its potential physiological function, while it is able to exert various degrees of influence upon these activities in blood coagulation by interacting with negatively charged phospholipids in vitro.
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PMID:Effects of calphobindin II (annexin VI) on procoagulant and anticoagulant activities of cultured endothelial cells. 139 5

An anticoagulant protein was purified from the EDTA extract of human placental tissue. The purified protein had a molecular weight of 73,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis under both reducing and non-reducing conditions. Because this protein had the ability to bind phospholipids such as phosphatidylserine, phosphatidylinositol, and cardiolipin in the presence of Ca2+, this protein was designated as calphobindin II (CPB-II). CPB-II prolonged the clotting time of normal plasma when coagulation was induced by tissue factor, cephalin and ellagic acid or recalcification, but did not affect thrombin-initiated fibrin formation. CPB-II also inhibited the activation of prothrombin by the complete prothrombinase complex or factor Xa-phospholipid-Ca2+ but not that by phospholipid-free factor Xa. In addition, CPB-II had an inhibitory activity against phospholipase A2.
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PMID:Isolation and characterization of an anticoagulant protein from human placenta. 252 73