Sandbox Reserved 1482: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 30: | Line 30: | ||
====The coagulation process==== | ====The coagulation process==== | ||
In response to an injury, the coagulation factor VIII is separated from von Willebrand factor. The active form | In response to an injury, the coagulation factor VIII is separated from von Willebrand factor. The active form (called “Factor VIIIa”) is obtained by a proteolytic cleavage of the B-domain of Factor VIII by [[Thrombin]] <ref name="wikipedia" /><ref name="Ngo" />. Then the two remaining chains are linked together thanks to a metal link (probably calcium ion) <ref name="Ngo" />. | ||
Thus the factor VIIIa is a non-covalent dimer <ref name="Ngo" />. | Thus the factor VIIIa is a non-covalent dimer <ref name="Ngo" />. | ||
It is the catalyst for the activation reaction of the factor X (to [[Factor Xa]]) by activated [[Factor IX]]a in the presence of calcium ion and phospholipids. | It is the catalyst for the activation reaction of the factor X (to [[Factor Xa]]) by activated [[Factor IX]]a in the presence of calcium ion and phospholipids. | ||
This activation reaction is accelerated approximately 200,000 times when factor VIII is present. <ref name="wikipedia" /><ref name="Ngo" /><ref name="El" /> | |||
Then, no longer protected by the von Willebrand factor, the factor VIIIa is proteolytically inactivated and quickly cleared from the blood stream, whereas, factor Xa becomes able (with the help of other factors) to stop the bleeding by forming a blood clot. <ref name="wikipedia" /><ref name="El" /> | Then, no longer protected by the von Willebrand factor, the factor VIIIa is proteolytically inactivated and quickly cleared from the blood stream, whereas, factor Xa becomes able (with the help of other factors) to stop the bleeding by forming a blood clot. <ref name="wikipedia" /><ref name="El" /> | ||
