Factor XI activation in a revised model of blood coagulation
D Gailani, GJ Broze Jr - Science, 1991 - science.org
D Gailani, GJ Broze Jr
Science, 1991•science.orgCoagulation factor XI is activated in vitro by factor XIIa in the presence of high molecular
weight kininogen (HMWK) and a negatively charged surface. Factor XII deficiency is not
associated with bleeding, which suggests that another mechanism for factor XI activation
exists in vivo. A revised model of coagulation is proposed in which factor XI is activated by
thrombin. In the absence of cofactors, thrombin is more effective (k cat K m= 1.6× 105) than
factor XIIa (1.7× 104) in activating factor XI. Dextran sulfate enhances activation of factor XI …
weight kininogen (HMWK) and a negatively charged surface. Factor XII deficiency is not
associated with bleeding, which suggests that another mechanism for factor XI activation
exists in vivo. A revised model of coagulation is proposed in which factor XI is activated by
thrombin. In the absence of cofactors, thrombin is more effective (k cat K m= 1.6× 105) than
factor XIIa (1.7× 104) in activating factor XI. Dextran sulfate enhances activation of factor XI …
Coagulation factor XI is activated in vitro by factor XIIa in the presence of high molecular weight kininogen (HMWK) and a negatively charged surface. Factor XII deficiency is not associated with bleeding, which suggests that another mechanism for factor XI activation exists in vivo. A revised model of coagulation is proposed in which factor XI is activated by thrombin. In the absence of cofactors, thrombin is more effective (kcatKm = 1.6 × 105) than factor XIIa (1.7 × 104) in activating factor XI. Dextran sulfate enhances activation of factor XI by thrombin 2000-fold; part of this effect is due to autoactivation of factor XI by activated factor XI.
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