Purified prothrombin can be converted into thrombin in different ways (2), namely, by the use of biological activators, by the action of high concentrations of sodium citrate, and by treatment with trypsin. Biological activation of prothrombin requires lipoprotein tissue-factor(s) that have prothrombin-converting or thromboplastic activity, protein serum-factor(s) which augment thromboplastic a...

The prothrombin of the blood is elaborated in the liver. Andrus et al. (1939), and Warren and Rhoads (1939) produced experimental evidence in support, of this hypothesis. By total and partial hepatectomy in animals they produced a profound reduction in plasma prothrombin concentration which was unaffected by treatment with vitamin K and bile salts. It has been found essential to have vitamin K ...

The conversion of prothrombin into thrombin by Factor Xa requires the cleavage of two peptide bonds in prothrombin. Dependent on the order of cleavage, prethrombin 2 or meizothrombin occurs as intermediate. Since prethrombin 2 has as yet been the only observed intermediate, prothrombin activation is generally considered to proceed via prethrombin 2. In this paper we present new methods that all...

Extirpation of a large portion of the liver in rats results in a marked decrease in the plasma prothrombin. The plasma prothrombin level gradually returns to normal during the period required for restoration of the liver to its normal weight. The decrease in prothrombin incident to partial hepatectomy supports the thesis that the liver is concerned in the manufacture of plasma prothrombin.

objective(s): echis carinatus is one of the venomous snakes in iran. the venom of iranian echis carinatus is a rich source of protein with various factors affecting the plasma protein and blood coagulation factor. some of these proteins exhibit types of enzymatic activities. however, other items are proteins with no enzymatic activity.   materials and methods: in order to study the mechanism an...

Interaction of certain metal ions with prothrombin and prothrombin fragment 1 has been shown to result in conformational change(s). Self-association of prothrombin and prothrombin fragment 1 in the presence of divalent cations has been reported. The present study has made use of a covalent cross-linking reagent, dithiobis(succinimidylpropionate), to study the self-association of prothrombin in ...

Vascular endothelial cells derived from adult bovine aorta (ABAE) treated with factor Xa and calcium were found to activate prothrombin. In contrast, nonvascular cells (human foreskin fibroblasts, bovine corneal endothelial cells, or human fetal lung cells) had either no or very little effect on prothrombin activation. In the presence of 6 X 10(5) ABAE cells, 20 ng of factor Xa converted 90 mic...

The kringle 2 domain of prothrombin has been shown to interact with factor Va during the activation of prothrombin by the prothrombinase complex composed of factor Xa, factor Va, negatively charged phospholipids and Ca2+ ions. However, contradictory results have been reported about the role of the kringle 1 domain of prothrombin during the assembly of the prothrombinase complex. In an attempt t...

BACKGROUND Congenital or acquired prothrombin deficiency is a rare condition. CASE REPORT A 2-year-7-month old Thai girl presented with ecchymosis, bleeding at both thighs and right ear lobe after a self-limited viral infection. RESULTS The investigations revealed prolonged APTT and PT, prothrombin level 6% and positive anticardiolipin antibody 26.2 IU/mL. The 1:1 mixture of her plasma and ...

Purified prothrombin can be converted into thrombin in different ways (2), namely, by the use of biological activators, by the action of high concentrations of sodium citrate, and by treatment with trypsin. Biological activation of prothrombin requires lipoprotein tissue-factor(s) that have prothrombin-converting or thromboplastic activity, protein serum-factor(s) which augment thromboplastic a...