Kininogen Quick Facts
- Molecular weight: 122 000 D
- Plasma-concentration: 74 – 84μg/ml
- Half-life: 144 hours
- Normal range: 70 – 130%
Biochemistry of Kininogen
High molecular weight kininogen (HMWK or Fitzgerald-factor) is a cofactor for the activation of prekallikrein, factor XII and factor XI. HMWK has its own enzyme activity.
HMWK has a multi-domain structure and numerous functions, inhibition of cystein proteases of the type of papain, participation in inflammatory processes and increase of the vessel permeability. By the cleavage of HMWK by kallikrein bradykinin is released. This causes an improvement of the microcirculation by vasodilatation.
Clinical significance of Kininogen
The rare hereditary HMWK-deficiency is seen from an extremely prolonged aPTT. Risk of bleeding or thrombosis is, however, not present.
Clinical or Research use of Kininogen
Suspected hereditary HMWK-deficiency, unexplained prolongation of the aPTT.
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