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Factor XIIa MeSH Descriptor Data 2025


MeSH Heading
Factor XIIa
Tree Number(s)
D08.811.277.656.300.760.324
D08.811.277.656.959.350.324
D12.776.124.125.450.324
D23.119.450.324
Unique ID
D015956
RDF Unique Identifier
http://id.nlm.nih.gov/mesh/D015956
Annotation
/defic = FACTOR XII DEFICIENCY
Scope Note
Activated form of factor XII. In the initial event in the intrinsic pathway of blood coagulation, kallikrein (with cofactor HIGH MOLECULAR WEIGHT KININOGEN) cleaves factor XII to XIIa. Factor XIIa is then further cleaved by kallikrein, plasmin, and trypsin to yield smaller factor XII fragments (Hageman-Factor fragments). These fragments increase the activity of prekallikrein to kallikrein but decrease the procoagulant activity of factor XII.
Entry Term(s)
Activated Factor XII
Blood Coagulation Factor XII, Activated
Coagulation Factor XIIa
Factor 12A
Factor Twelve A
Factor XII, Activated
Hageman-Factor Fragments
Prekallikrein Activator
Registry Numbers
EC 3.4.21.38
0
Previous Indexing
Factor XII (1966-1989)
Peptide Fragments (1979-1987)
Serine Proteinases (1988-1989)
See Also
Coagulants
Public MeSH Note
90
History Note
90
Date Established
1990/01/01
Date of Entry
1989/05/25
Revision Date
2019/05/30
Factor XIIa Preferred
Hageman-Factor Fragments Narrower
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