scholarly journals Interaction of manganese with bovine factor X.

1977 ◽  
Vol 252 (14) ◽  
pp. 4758-4761 ◽  
Author(s):  
S P Bajaj ◽  
R Byrne ◽  
T Nowak ◽  
F J Castellino
Keyword(s):  
Factor X ◽  
Bovine Factor

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.

scholarly journals The role of phospholipid and factor VIIIa in the activation of bovine factor X.

1981 ◽  
Vol 256 (7) ◽  
pp. 3433-3442 ◽  
Author(s):  
G. van Dieijen ◽  
G. Tans ◽  
J. Rosing ◽  
H.C. Hemker
Keyword(s):  
Factor X ◽  
Factor Viiia ◽  
Bovine Factor

scholarly journals The endotoxin-induced procoagulant of mouse exudate macrophages: a factor-X activator

Blood ◽  
1983 ◽  
Vol 62 (2) ◽  
pp. 333-340 ◽  
Author(s):  
JW Jr Shands
Keyword(s):  
Tissue Factor ◽  
Culture Supernatant ◽  
Factor Vii ◽  
Mouse Tissue ◽  
Factor X ◽  
Macrophage Culture ◽  
Cellular Factor ◽  
Culture Supernatants ◽  
Bovine Factor

Abstract The properties of mouse macrophage procoagulant induced by endotoxin in vitro were studied by the acceleration of clotting and by chromogenic assays using as substrates human plasma and bovine components, which are not activated by mouse tissue factor. Maximal macrophage procoagulant activity occurred when activated cells were lysed in culture supernatant fluids, suggesting the interaction of cellular and supernatant factors. This procoagulant was clearly able to activate bovine factor X. The procoagulant also appeared to have prothrombinase activity. However, additional experiments suggested that the bulk of this activity was due to the activation of factor X contaminating the prothrombin. The production of the procoagulant was inhibited by warfarin (5 microM). Its activity was inhibited by 1 mM diisopropylfluorophosphate and unaffected by iodoacetamide, indicating that the procoagulant is a serine protease. Macrophage culture supernatants contained factor-VII-like activity. Neither mouse tissue factor nor macrophage culture supernatants alone activated bovine factor X. The two combined served as an efficient factor-X activator. Active supernatant factor (factor-VII-like) was not produced by macrophages cultured in the presence of warfarin, while the production of the macrophage cellular factor was unaffected by the presence of warfarin. I conclude that exudate macrophages cultured in vitro make and secrete factor VII or a factor-VII-like substance into the culture supernatant. When activated macrophages are lysed in this supernatant, the interaction of a cellular factor (? tissue factor) and factor VII gives rise to a factor-X activator.

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

scholarly journals The endotoxin-induced procoagulant of mouse exudate macrophages: a factor-X activator

Blood ◽  
1983 ◽  
Vol 62 (2) ◽  
pp. 333-340
Author(s):  
JW Jr Shands
Keyword(s):  
Tissue Factor ◽  
Culture Supernatant ◽  
Factor Vii ◽  
Mouse Tissue ◽  
Factor X ◽  
Macrophage Culture ◽  
Cellular Factor ◽  
Culture Supernatants ◽  
Bovine Factor

The properties of mouse macrophage procoagulant induced by endotoxin in vitro were studied by the acceleration of clotting and by chromogenic assays using as substrates human plasma and bovine components, which are not activated by mouse tissue factor. Maximal macrophage procoagulant activity occurred when activated cells were lysed in culture supernatant fluids, suggesting the interaction of cellular and supernatant factors. This procoagulant was clearly able to activate bovine factor X. The procoagulant also appeared to have prothrombinase activity. However, additional experiments suggested that the bulk of this activity was due to the activation of factor X contaminating the prothrombin. The production of the procoagulant was inhibited by warfarin (5 microM). Its activity was inhibited by 1 mM diisopropylfluorophosphate and unaffected by iodoacetamide, indicating that the procoagulant is a serine protease. Macrophage culture supernatants contained factor-VII-like activity. Neither mouse tissue factor nor macrophage culture supernatants alone activated bovine factor X. The two combined served as an efficient factor-X activator. Active supernatant factor (factor-VII-like) was not produced by macrophages cultured in the presence of warfarin, while the production of the macrophage cellular factor was unaffected by the presence of warfarin. I conclude that exudate macrophages cultured in vitro make and secrete factor VII or a factor-VII-like substance into the culture supernatant. When activated macrophages are lysed in this supernatant, the interaction of a cellular factor (? tissue factor) and factor VII gives rise to a factor-X activator.

The Clotting of a Snake (Crotalus Viridis Helleri) Plasma and its Interaction with Various Snake Venoms

1976 ◽  
Vol 35 (02) ◽  
pp. 314-323 ◽  
Author(s):  
K.W.E Denson
Keyword(s):  
Human Plasma ◽  
Factor Xa ◽  
Factor X ◽  
Snake Venoms ◽  
Crotalus Viridis ◽  
Fibrin Monomer ◽  
Russell’S Viper ◽  
Marked Specificity ◽  
Bovine Factor

SummaryThe clotting of C. V. Helleri plasma is not accelerated by the factor X activator or throm-bin-like enzymes from its own venom. Clotting of the plasma is accelerated by the factor X activator from Russell’s viper venom, but not by the thrombin-like enzyme from Agkistrodon Rhodostoma venom (“Arvin”).The prothrombin activator from the Taipan venom clots C. V. Helleri plasma equally well as human plasma, but the thrombin which is produced has a marked specificity for its own fibrinogen, and clots bovine fibrinogen more slowly.C. V. Helleri plasma contains an inhibitor which progressively inactivates bovine factor Xa and thrombin, but the inhibitor is not potentiated by heparin. The slow, protracted clotting of the snake plasma either alone or when mixed with human plasma or bovine fibrinogen suggests that this inhibitor may interfere with the polymerisation of fibrin monomer.

Activation of Bovine Factor X in the Presence of Calcium, Magnesium, Barium or Manganese ion

1978 ◽  
Vol 40 (02) ◽  
pp. 358-367 ◽  
Author(s):  
Robert H Yue ◽  
Menard M Gertler
Keyword(s):  
Metal Ions ◽  
Binding Site ◽  
Metal Ion ◽  
Factor Xa ◽  
Divalent Metal ◽  
Activation Process ◽  
Factor X ◽  
Divalent Metal Ion ◽  
Russell’S Viper ◽  
Bovine Factor

SummaryThe binding of divalent metal ions to bovine factor X, factor Xa and the coagulant protein in Russell’s viper venom was studied by the technique of fluorescence quenching. Titration of factor X with Ca+2, Mg+2 or Ba+2 revealed that these metal ions can bind to factor X. A tightly binding site(s) was observed with Kd of 79 and 98 μM for Ca+2 and Mg+2 respectively. A loosely binding site(s) was evident with Kd of 0.55, 0.50 and 0.35 mM for Ca+2, Mg+2 and Ba+2 respectively. The quenching phenomenon was also observed when Mn+2 was used as titrant but factor X precipitated out when the concentration of Mn+2 was 10 mM. The binding of Ca+2, Mg+2, Ba+2 or Mn+2 to bovine factor Xa or to the purified coagulant fraction of Russell’s viper venom was very weak in each case.In the absence of Ca+2, the coagulation fraction of Russell’s viper venom could not activate bovine factor X. Activation of factor X was achieved when Ca+2 was replaced by either Mg+2, Ba+2 or Mn+2. When the concentration of these ions were 5 mM, the efficiency of factor Xa generation was estimated to be: Ca+2> Mg+2> Ba+2> Mn+2. Higher concentration of Mg+2, Ba+2, or Mn+2 retarded the activation process. However, Ca+2, Mg+2, Ba+2 or Mn+2 has little or no influence on the esterase activity of factor Xa or purified Rusell’s viper venom.The results suggest that complexation of divalent metal ion with factor X is prerequisite in the activation process. The binding of Mg+2, Ba+2 or Mn+2 to these loosely binding sites might have altered the geometrical configuration as well as the electrostatic environment on factor X significantly. Thus, it is more difficult to form the binary complex and a slower generation of factor Xa results. Therefore, divalent metal ion serves as a dual role in the activation of factor X to factor Xa depending upon the ionic concentration.

BINDING OF CALCIUM TO HUMAN AND BOVINE FACTOR X

1987 ◽  
Author(s):  
D M Monroe ◽  
D W Deerfield ◽  
D L Olson ◽  
T N Stewart ◽  
H R Roberts ◽  
...  
Keyword(s):  
Binding Site ◽  
Binding Sites ◽  
Calcium Binding ◽  
Human Factor ◽  
Equilibrium Dialysis ◽  
Equilibrium Constants ◽  
Scatchard Analysis ◽  
Factor X ◽  
Amino Terminal ◽  
Bovine Factor

Human and bovine factor X contain 11 and 12 glutamyl residues respectively within the first forty amino terminal residues that are posttranslationally modified to y-carboxyglutamyl (Gla) residues. Calcium binding to these Gla residues and at other sites is critical for activity in factor X. We have measured calcium binding to human factor X by equilibrium dialysis for the first time. We have also re-examined calcium binding to bovine factor X in order to compare the two species. Factor X (10 μM) was incubated with 45Ca in 20 mM Tris (pH 7.5), 100 mM NaCl in a half cell separated by a 12-14000 molecular weight fast-equilib-rium disk membrane at 25°C for 24 hours. Four aliquots (100 μL each) were removed from each side of the cell and counted. Data were analyzed with a variety of models that allow for more than one class of binding site and for cooperativity among binding sites. Calcium binding to bovine factor X was best simulated by a model that assumes 1 very tight site, 3 cooperative tight sites, and 18 equivalent, non-interacting sites. Based on data from des(Gla)factor X, the first site is probably a high affinity non-Gla binding site. Our results differ from two previously published reports that indicated either 1 tight and 39 loose noncooperative sites (R.H. Yue & M.M. Gertler (1978) Thrombos. Haemostas. (Stuttg.) 40, 350) or 20 calcium binding sites with the first 4 being cooperative (M.J. Lindhout & H.C. Hemker (1978) Biochimica Biophysica Acta 533, 318). Our data on human factor X fit the same model as used for bovine factor X; however, coop-erativity is less in the 3 cooperative sites. Shown below are the first six thermodynamic equilibrium constants derived from a Scatchard analysis of binding data (values are M−1).Both proteins demonstrate the same total number of binding sites and essentially the same value for the first, tight binding site. Bovine factor X exhibits cooperativity, whereas human factor X has reduced cooperativity.

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