The Activation of Factor VIII by Thrombin

Özge-Anwar, Ayse H.; Connell, G. E.; Mustard, J. F.

doi:10.1182/blood.v26.4.500.500

Cited by 22 publications

(4 citation statements)

References 10 publications

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“…Thrombin has been reported to increase the coagulant activity of factor VIII (Rapaport et al, 1963(Rapaport et al, , 1965Macfarlane et al, 1964;Ozge-Anwar et al, 1965;Legaz et al, 1973Legaz et al, , 1975Shapiro et al, 1973). Factor Xa has also been shown to result in the activation of factor VIII .…”

Section: Resultsmentioning

confidence: 99%

Preparation and properties of bovine factor VIII (antihemophilic factor)

Vehar¹,

Davie²

1980

Biochemistry

519

214

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Factor VIII has been purified approximately 300000-fold from bovine plasma by ammonium sulfate fractionation, glycine precipitation, DEAE-Sephadex column chromatography, sulfate--Sepharose column chromatography, Sephadex G-200 gel filtration, and factor X--Sepharose column chromatography. The highly purified preparation migrated as a triplet on sodium dodecyl sulfate/urea--polyacrylamide gel electrophoresis with apparent molecular weights of 93000, 88000, and 85000. The coagulant activity of the purified preparations was inhibited by antibodies raised in rabbits against either the purified factor VIII protein or a preparation of factor VIII/von Willebrand factor. Antibodies to the purified protein also inhibited the coagulant activity of factor VIII/von Willebrand factor preparations. The purified factor VIII contained no platelet-aggregating activity, as measured in human platelet-rich plasma. The purified preparation of factor VIII was required for the activation of factor X in the presence of factor IXa, calcium, and phospholipid. It was activated about 30-fold by thrombin or factor Xa plus calcium and phospholipid, and each of these reactions was accompanied by a change in the sodium dodecyl sulfate/urea--polyacrylamide gel electrophoresis pattern of the protein. Factor VIII was rapidly inactivated by bovine-activated protein C in a reaction requiring calcium and phospholipid. This reaction was also associated with a change in the sodium dodecyl sulfate/urea--polyacrylamide gel electrophoresis pattern of the highly purified protein. These experiments involving three highly specific serine proteases support the conclusion that the triplet observed on polyacrylamide gels is factor VIII.

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Section: Resultsmentioning

confidence: 99%

Preparation and properties of bovine factor VIII (antihemophilic factor)

Vehar¹,

Davie²

1980

Biochemistry

519

214

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“…In particular, there is no equivalent for the anti-Xa test system in the in vivo experiments. Second, it has been shown that even small amounts of Ila can activate various coagulation proteases such as F V, F VIII, F VII and F XI resulting in massive feedback coagulation activation (25)(26)(27)(28)(29)(30). Suppression of Ila generation either by inhibition of Xa by LMWH or of Ila by UFH may cause a marked reduction of Ila-induced feedback activation of the coagulation system and, subsequently, a (possibly comparable) reduction ofF 1 + 2 , TAT and FPA generation.…”

Section: Discussionmentioning

confidence: 99%

Effects of a Low Molecular Weight Heparin (Fragmin®) and of Unfractionated Heparin on Coagulation Activation at the Site of Plug Formation In Vivo

Eichinger¹,

Wolz²,

Nieszpaur-Los³

et al. 1994

Thromb Haemost

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SummaryThe clinical benefits of unfractionated heparin (UFH) and low molecular weight heparin (LMWH) have been shown in many trials. However, the mode of action of heparin has not been fully elucidated. Thus, we wanted to study the effects of UFH and LMWH in vivo by measuring coagulation activation markers in blood obtained directly from a vascular injury site. In a double-blind, randomized, 3-way, cross-over study 18 healthy volunteers were given UFH (150 U/kg s.c.) and 2 doses of LMWH [35 U/kg s.c. (low dose, Id), 75 U/kg s.c. (high dose, hd)]. Prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT) and fibrinopeptide A (FPA) were measured in bleeding time blood and in venous blood before and after drug application. In addition, the effects of UFH and LMWH on in vitro coagulation tests were studied. Compared to base line, UFH and both IdLMWH and hdLMWH caused significant reductions of F1+2, TAT and FPA in bleeding time blood at 2 h. A marked effect of UFH and of hdLMWH was also seen at 5 h. The inhibition of FPA generation was more pronounced after hdLMWH compared to IdLMWH. In venous blood, UFH and LMWH caused reductions of F1+2, but not of TAT and FPA. In vitro, UFH predominantly affected the anti-IIa assays (activated partial thromboplastin time, thrombin time) and LMWH mainly the anti-Xa test system. Using a technique that investigates the activated coagulation system in vivo, a time- and dose dependent inhibitory effect of heparin on coagulation activation was detectable. Therefore, in our experimental setting a preferential inhibition of a particular portion of the coagulation system by one of the two heparin preparations was not detectable.

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“…The substrates for these assays were plasmas congenitall y deficient in these factors 1 ) or artificially depleted with celite. Normal PPP and that deficient in factor XII was collected and processed as describ ed before (32). Normal PPP was rendered deficient in factor XI by adsorption with 6 mg Celite 512 per m l plasma, or exh austed of factors XII and XI by adsorption with 50 mg/ml according to Nossel (30).…”

Section: Clotting T Estsmentioning

confidence: 99%

The Kinin System of Human Plasma

Özge-Anwar¹,

Movat²,

Scott³

1972

Thromb Haemost

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SummaryHuman plasma was adsorbed to celite. The celite eluates were chromatographed on QAE-Sephadex A-50, followed by gel filtration, isoelectric focusing and preparative polyacrylamide electrophoresis.By anion-exchange chromatography, factor XI a, kallikrein and y-globulin were isolated from the excluded protein peak. Factor XIa (MW ∼170,000) corrected the deficiency in plasmas deficient in factors XII or XI, but had no effect on the kininsystem. Its isoelectric point was about 8.0-8.5. Kallikrein had a molecular weight of ∼ 90,000 and a pi of 7.8-8.0 The two substances could be isolated also by polyacrylamide electrophoresis.Highly anionic fractions contained a fragment of factor XII a (prekallikrein activator), which activated prekallikrein and retained some of the clot-promoting property of the intact factor XIIa molecule. Its molecular weight was about 37,000, the pi about 4.4 and it migrated as a prealbumin by disc electrophoresis.It is concluded that, by massive contact exposure, most of factor XII a converts to the highly anionic, low-molecular-weight prekallikrein activator. Since the prekallikrein activator is a fragment of factor XII a, we recommend that it be referred to as “XII f”.

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The Activation of Factor VIII by Thrombin

Cited by 22 publications

References 10 publications

Preparation and properties of bovine factor VIII (antihemophilic factor)

Preparation and properties of bovine factor VIII (antihemophilic factor)

Effects of a Low Molecular Weight Heparin (Fragmin®) and of Unfractionated Heparin on Coagulation Activation at the Site of Plug Formation In Vivo

The Kinin System of Human Plasma

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