The Formation of the Extrinsic Prothrombin Activator

Summary

The formation of the extrinsic activator of prothrombin conversion is investigated. We use the term “extrinsic activator” to avoid ambiguity which could arise when employing the name tissue thromboplastin.

The experiments are carried out with purified clotting factors and congenital factor VII and X-deficient sera. Two steps can be distinguished. First, tissue factor and factor X react together as substrates in presence of Ca ions to form the extrinsic reaction product. The reaction is catalyzed enzymatically by factor VII. In the second stage, the reaction product and factor V (substrate) form the extrinsic activator which in turn can convert the prothrombin to thrombin.

• References

• 1 Bachmann F, Duckert F, Geiger M, Baer P, Koller F. Differentiation of the Factor VII Complex. Studies on the Stuart-Power Factor. Thromb. Diath. haem. 01: 169 1957;
• 2 Bachmann F, Duckert F, Koller F. The Stuart-Power Factor Assay and Its Clinical Significance. Thromb. Diath. haem. 02: 24 1958;
• 3 Biggs R, Macfarlane R. G. Human Blood Coagulation and Its Disorders. 2nd Ed.. Blackwell; Oxford: 1957
• 4 Clauss A. Gerinnungsphysiologische Schnellmethode zur Bestimmung des Fibrinogens. Acta haemat. (Basel) 17: 237 1957;
• 5 Duckert F, Koller F, Matter M. Purification and Physiological Properties of Factor VII from Plasma and Serum. Separation from Prothrombin. Proc. Soc. exp. Biol. (N.Y) 82: 259 1953;
• 6 Duckert F, Loeliger A, Koller F. Sur un Nouveau Facteur de la Coagulation, le Facteur VII. Sa Purification. Helv. 34: 2431 1951;
• 7 Duckert F, Yin T. E, Straub W. VIII Colloquium. Protides of the Biological Fluids. Sint-Janshospitaal, Brugge. Belgium: May 1960. Separation and Purification of the Blood Clotting Factors by means of Chromatography and Electrophoresis. Preparative Methods.
• 8 Fisch U, Duckert F. Some Aspects of Kinetics of the First Stages of Thromboplastin Formation. Thromb. Diath. haem. 03: 98 1959;
• 9 Geiger M, Duckert F, Koller F. Quantitative Bestimmungen von Faktor VIII und IX bei Blutersippen. 413 5th Cong. Europ. Soc. Haemat. Freiburg i. B; 1956
• 10 Hardisty R. M. The Reaction of Blood Coagulation Factors with Brain Extract. Brit. J. Haemat. 01: 323 1955;
• 11 Hjort P. Intermediate Reactions in the Coagulation of Blood with Tissue Thromboplastin. Scand. J. clin. Lab. Invest 09 suppl. 27, 183 1957;
• 12 Hougie C. Reactions of Stuart Factor and Factor VII with Brain and Factor V. Proc. Soc. exp. Biol. (N.Y) 101: 132 1959;
• 13 Kappeler R. Das Verhalten von Faktor V im Serum unter normalen und pathologischen Bedingungen. Z. klin. Med. 153: 103 1955;
• 14 Koller F, Loeliger A, Duckert F. Experiments on a New Clotting Factor. Factor VII. Acta haemat. (Basel) 06: 1 1951;
• 15 Quick A. J. The Nature of the Bleeding in Jaundice J. A. M. A. 110: 1658 1938;
• 16 Straub W. Separation of Coagulation Factors by means of Starch Gel Electrophoresis. Thromb. Diath. haem. 04: 451 1960;
• 17 Surgenor D. M, Wilson N. A, Henry A. S. Factor V from Human Plasma. Thromb. Diath. haem. 05: 1 1960;
• 18 Waaler B. A. Simultaneous Contribution to the Formation of Thrombin by the Intrinsic and Extrinsic Blood Clotting Systems. Scand. J. clin. Lab. Invest 09: 322 1957;
• 19 Zollinger W. Personal Communication. To be published.