Mannan-binding lectin-associated serine protease-1 (MASP-1), a protein of the complement lectin pathway, resembles thrombin in terms of structural features and substrate specificity. Due to its interplay with several coagulation factors, it has the ability to induce fibrin clot formation independent of the usual coagulation activation pathways. We have recently shown that MASP-1 activates proth...

Long-standing dogma proposes a profound contribution of membrane binding by prothrombin in determining the rate at which it is converted to thrombin by prothrombinase. We have examined the action of prothrombinase on full-length prothrombin variants lacking γ-carboxyglutamate modifications (desGla) with impaired membrane binding. We show an unexpectedly modest decrease in the rate of thrombin f...

Regulation of vascular homeostasis depends upon collaboration between cells of the vessel wall and blood coagulation system. A direct interaction between integrin alphaVbeta3 on endothelial cells and smooth muscle cells and prothrombin, the pivotal proenzyme of the blood coagulation system, is demonstrated and activation of the integrin is required for receptor engagement. Evidence that prothro...

Attention has recently been focused on the consumption of prothrombin during blood coagulation. Studies of the velocity of prothrombin conversion to thrombin have yielded important information concerning the clotting defect in various hemorrhagic disorders. Thrombin evolution is retarded in the coagulation of hemophilic blood (1-5), thrombocytopenic blood (3, 4, 6, 7) and blood exposed to silic...

By RICHARD WARREN, M.D. AND JOHN S. BELKO, M.S. A PRACTICAL CLINICAL METHOD for determining the activity in plasma of the accelerators of prothrombin conversion has not been so rapidly forthcoming as have been descriptions of their properties and reactions. Those methods which have been described have employed two general principles. The first. of these is the ability of the unknow’n plasma to ...

S TUDIES of the chemical nature of prothrombin have indicated a glycoprotein structure.2 Data obtained on purified bovine prothrombin have shown the reducing sugar content to be approximately 5 per cent, based on a reference standard of galactose and mannose.35 Laki et al.5 reported a value of 6.5 per cent in terms of glucose, and 1.6 to 1.7 per cent hexosamine. Alexander6 and colleagues observ...

congenital factor x deficiency is a rare autosomal recessive bleeding disorder that presents with variable bleeding tendency and prolonged coagulation tests, prothrombin time, and partial thromboplastin time. thromboembolic events have not been reported in patients with factor x deficiency yet. herein, we report a patient with factor x deficiency who had recurrent venous thromboembolic events.

background: inherited thrombophilic gene polymorphisms have been related to the pathogenesis of venous thromboembolism and its outcomes. considering the scarcity of data on the frequency of the thrombophilic gene polymorphisms in iranian populations, the aim of this study was to assess such polymorphisms in healthy individuals. materials and methods: this cross-sectional study was performed on ...

Prothrombin precursors undergo several modifications before secretion from the liver. These include signal-peptide cleavage (Friezner-Degen et al., 1983), complex glycosylation (Mizuochi et al., 1979) anddisulphide-bridge formation (Magnusson et al., 1975). Moreover, the function of plasma prothrombin is absolutely dependent upon the presence, at its N-terminus, of ten residues of y-carboxyglut...

OBJECTIVE Individuals with elevated prothrombin, including those with the prothrombin G20210A mutation, have increased risk of venous thrombosis. Although these individuals do not have increased circulating prothrombotic biomarkers, their plasma demonstrates increased tissue factor-dependent thrombin generation in vitro. The objectives of this study were to determine the pathological role of el...