scholarly journals erythro -β-hydroxyaspartic acid in bovine factor IX and factor X

FEBS Letters ◽  
1984 ◽  
Vol 165 (1) ◽  
pp. 102-106 ◽  
Author(s):  
Teruko Sugo ◽  
Per Fernlund ◽  
Johan Stenflo
Keyword(s):  
Factor Ix ◽  
Factor X ◽  
Bovine Factor

Activation of Bovine Factor IX By Bovine Factor XIa . Active Site Titration Of Factor IXa and Development of A spectro-Photometric assay for Factor IX

1981 ◽  
Author(s):  
G Tans ◽  
T Janssen-Claessen ◽  
G v Dieijen ◽  
J Rosing ◽  
H C Hemker
Keyword(s):  
Active Site ◽  
Human Factor ◽  
Factor Ix ◽  
Plasma Samples ◽  
Factor X ◽  
Clotting Factors ◽  
Factor Ixa ◽  
Human Factor Ix ◽  
Factor Xia ◽  
Bovine Factor

Activation of factor IX by factor XIa occurs via an intermediate which has no esterase activity towards synthetic arginine esters or coagulant activity as determined with a clotting assay. Factor IXa can be active site titrated using p-nitrophenyl-p1-guanidinobenzoate (p-NPGB) as a titrant. The rate and equilibrium constants describing the active site titration will be presented. To determine whether the intermediate occurring during factor IX activation by factor XIa has its active site exposed for p-NPGB the time course of activation of factor IX by factor XIa was followed l) by active site titration of the active sites generated, 2) by gel- electrophoretic analysis in the presence of sodium dodecyl sulfate, 3) by a clotting assay for factor IXa and 4) by measurement of factor IXa using a spectrophotomefric assay. It will be shown that the intermediate occurring during activation of factor IX by factor XIa does not interact with p-NPGB indicating that the active site is not available in the intermediate.Factor IXa can be determined spectrophotometrically by measurement of the rate of factor X activation by factor IXa in the presence of phospholipid and CaCl2. The factor Xa generated is measured using the chromogenic substrate S222. Since human factor IX can be activated with bovine factor XIa and since human factor IXa can activate bovine factorX the bovine clotting factors factor XIa and factor X can be used to construct an assay for factor fx in plasma samples. Experiments will be presented in which it is shown that the spec- trophotometric assay for human factor IXa can be used to determine levels of factor IX in plasma samples of healthy individuals, in plasma samples deficient in various clotting factors and in plasma samples from patients under anti-coagulant therapy. The results are in agreement with a factor IX clotting test.

scholarly journals Bovine factor IX (christmas factor). Further evidence of homology with factor X (Stuart factor) and prothrombin

FEBS Letters ◽  
1974 ◽  
Vol 47 (1) ◽  
pp. 132-135 ◽  
Author(s):  
David L. Enfield ◽  
Lowell H. Ericsson ◽  
Kazuo Fujikawa ◽  
K. Titani ◽  
Kenneth A. Walsh ◽  
...  
Keyword(s):  
Factor Ix ◽  
Factor X ◽  
Bovine Factor

Very Low Activated Factor VII and Reduced Factor VII Antigen in Familial Abetalipoproteinaemia

1998 ◽  
Vol 80 (08) ◽  
pp. 233-238 ◽  
Author(s):  
K. A. Mitropoulos ◽  
M. N. Nanjee ◽  
D. J. Howarth ◽  
J. C. Martin ◽  
M. P. Esnouf ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Positive Association ◽  
Factor Ix ◽  
Factor Vii ◽  
Unesterified Fatty Acid ◽  
Factor Xii ◽  
Factor X ◽  
Factor Xi ◽  
Activated Factor Vii ◽  
Normal Mean

SummaryAbetalipoproteinaemia is a rare disorder of apolipoprotein B metabolism associated with extremely low plasma concentrations of triglyce-ride. To discover whether the general positive association between factor VII and triglyceride levels extends to this condition, 5 patients were compared with 18 controls. All patients had a triglyceride below 100 μmol/l. Plasma unesterified fatty acid concentration was normal. Although factor IX activity was only slightly reduced (mean 88% standard) and factor IX antigen was normal, mean activated factor VII in patients was strikingly reduced to 34% of that in controls, a level similar to that found in haemophilia B. The patients’ mean factor VII activity and factor VII antigen were also significantly reduced to 54% and 63% of those in controls, respectively. Mean factor XI activity and tissue factor pathway inhibitor activity were reduced in patients to 70% and 75% of control values respectively, while factor XII, factor XI antigen, factor X, prothrombin and protein C were normal.

Markers of Hypercoagulability in Patients with Hemophilia B Given Repeated, Large Doses of Factor IX Concentrates during and after Surgery

1994 ◽  
Vol 71 (06) ◽  
pp. 737-740 ◽  
Author(s):  
E Santagostino ◽  
P M Mannucci ◽  
A Gringeri ◽  
G Tagariello ◽  
F Baudo ◽  
...  
Keyword(s):  
High Risk ◽  
Ex Vivo ◽  
Factor Ix ◽  
Hemophilia B ◽  
Coagulation System ◽  
Prolonged Treatment ◽  
Orthopedic Procedures ◽  
Factor X ◽  
Prothrombin Complex Concentrates ◽  
Increased Risk

SummaryPurer factor IX (FIX) concentrates have been produced for the treatment of hemophilia B in the attempt to reduce the risk of thrombotic complications associated with the use of prothrombin complex concentrates. To evaluate ex vivo whether or not FIX concentrates activate the coagulation system in conditions associated with a high risk for thrombosis, we measured markers of hypercoagulability in 10 patients with hemophilia B who underwent surgery, mainly orthopedic procedures, covered by multiple concentrate infusions (40-80 U/kg/day). Postinfusion plasma levels of prothrombin fragment 1+2 and factor X activation peptide did not differ significantly from the presurgical levels, neither before nor after each concentrate dose. Therefore, it appears that prolonged treatment of patients with hemophilia B undergoing high risk surgical procedures with high doses of FIX concentrate does not cause systemic activation of coagulation. This suggests that purified FIX concentrates are preferable to prothrombin complex concentrates for conditions associated with an increased risk of thrombosis.

The Activation of Human Factor X in Sodium Citrate: the Role of Factor VII

1976 ◽  
Vol 36 (01) ◽  
pp. 104-114 ◽  
Author(s):  
D. L Aronson ◽  
A. J Mustafa
Keyword(s):  
Sodium Citrate ◽  
Human Factor ◽  
Deae Cellulose ◽  
Factor Ix ◽  
Factor Vii ◽  
Factor X

SummaryHuman factor X was purified by several different procedures yielding products which had varying amounts of factor VII and factor IX. Treatment with CHC13 during the fractionation of the factor X removed 95% of the factor VII and factor IX activity and the resulting factor X activated more slowly when incubated in 25% sodium citrate. Removal of residual factor VII by DEAE cellulose chromatography yielded a factor X which activated still more slowly and less completely. When the factor VII, removed by chromatography, was added to the chromatographed factor X, the ability to be activated in 25% sodium citrate was restored. Confirmatory evidence for the role of factor VII in this reaction was the inhibition of the conversion of the factor X by both DFP and SBTI.

The Binding of Calcium Ions to Bovine Factor X by Rate Dialysis

1978 ◽  
Vol 40 (02) ◽  
pp. 350-357
Author(s):  
Robert H Yue ◽  
Menard M Gertler
Keyword(s):  
Molecular Weight ◽  
Dissociation Constant ◽  
Calcium Ions ◽  
Activation Process ◽  
Factor X ◽  
The Real ◽  
High Affinity ◽  
Binding Data ◽  
Sequential Mechanism ◽  
Bovine Factor

SummaryThe binding of Ca+2 to bovine factor X (molecular weight of 74,000) (Yue und Gertler 1977) was studied by the technique of rate dialysis and with the use of 45Ca+2. The binding data are consistent with a model of sequential mechanism. One mole of Ca+2 binds to the glycoprotein with a dissociation constant of 5.2 × 10-5 M and an additional 39 ± 4 moles of Ca+2 bind to this zymogen with a dissociation constant of 3.7 × 10-3M. The binding of the high affinity Ca+2 causes a functionally significant change in the zymogen, and (calcium) (factor X) complex is the real substrate in the activation process by the protease in Russell’s viper venom.

Spectrophotometric Determination of Factor Xa Generation in Factor IX Concentrates

1977 ◽  
Vol 37 (03) ◽  
pp. 535-540 ◽  
Author(s):  
D. S Pepper ◽  
D Banhegyi ◽  
Ann Howie
Keyword(s):  
Intrinsic Factor ◽  
Factor Xa ◽  
Factor Ix ◽  
Factor V ◽  
Factor X ◽  
Generation Times ◽  
Incubation Periods ◽  
Multiple Sample ◽  
Recording Spectrophotometer

SummaryPrevious work from this department, concerned with testing the potential thrombogenicity of therapeutic factor IX concentrates, demonstrated that following recalcification of factor IX concentrates thrombin was generated within 3-30 minutes of incubation (Sas et al. 1975). The test developed (known as the TGt 50 test) is a two-stage assay and was thus found to be time consuming, tedious and tended to become inaccurate with long incubation periods and a large number of samples. A semiautomatic version of the test is reported in which the synthetic peptide Bz-ILE-GLU-GLY-ARG-pNA (S-2222) is added to recalcified, diluted factor IX concentrate in the micro-cuvette of a multiple sample recording spectrophotometer. Information can be obtained on (a) the amount of Xa (if any) present prior to recalcification (b) the initial amount of Xa formed and (c) the time taken to activate all factor X to Xa. Direct graphical interpretation shows a number of qualitative differences between commercial preparations, but by either of the criteria (b) or (c) above, it is possible to place the different products into “activated” and “non activated” groups such that both the Xa generation times and TGt 50 tests identify the same two groups of products. This agreement also indicates that the TGt 50 test is independent of the intrinsic factor V levels in the various concentrates.

The Formation of Intermediate Product I in a Purified System The Role of Factor IX or of its Precursor and of a Hageman Factor-PTA Fraction

1961 ◽  
Vol 6 (02) ◽  
pp. 224-234 ◽  
Author(s):  
E. T Yin ◽  
F Duckert
Keyword(s):  
Intermediate Product ◽  
Factor Ix ◽  
Assay Method ◽  
Lag Phase ◽  
Factor X ◽  
Haemophilia B ◽  
Hageman Factor ◽  
One Stage ◽  
The One

Summary1. The role of two clot promoting fractions isolated from either plasma or serum is studied in a purified system for the generation of intermediate product I in which the serum is replaced by factor X and the investigated fractions.2. Optimal generation of intermediate product I is possible in the purified system utilizing fractions devoid of factor IX one-stage activity. Prothrombin and thrombin are not necessary in this system.3. The fraction containing factor IX or its precursor, no measurable activity by the one-stage assay method, controls the yield of intermediate product I. No similar fraction can be isolated from haemophilia B plasma or serum.4. The Hageman factor — PTA fraction shortens the lag phase of intermediate product I formation and has no influence on the yield. This fraction can also be prepared from haemophilia B plasma or serum.

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