EC - Coagulation factor XIIa

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IntEnz Enzyme Nomenclature


Accepted name:
coagulation factor XIIa
Other names:
Hageman factor (activated)
Hageman factor β-fragment
Hageman factor fragment HFf
activated β blood-coagulation factor XII
blood-coagulation factor XIIaβ
blood-coagulation factor XIIf
kallikreinogen activator
prealbumin activator
prekallikrein activator
Systematic name:



Also activates plasminogen and plasma prokallikrein. Formed from the proenzyme, factor XII, by plasma kallikrein or factor XIIa. In peptidase family S1 (trypsin family).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , MEROPS , UniPathway
Protein domains and families: PROSITE:PDOC00124
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004252
CAS Registry Number: 75216-42-1


  1. Fujikawa, K. and Davie, E.W.
    Human factor XII (Hageman factor).
    Methods Enzymol. 80C : 198-211 (1981). [PMID: 6918768]
  2. Cho, K., Tanaka, T., Cook, R.R., Kisiel, W., Fujikawa, K., Kurachi, K. and Powers, J.C.
    Active-site mapping of bovine and human blood coagulation serine proteases using synthetic peptide 4-nitroanilide and thio ester substrates.
    Biochemistry 23 : 644-650 (1984). [PMID: 6370301]
  3. Que, B.G. and Davie, E.W.
    Characterization of a cDNA coding for human factor XII (Hageman factor).
    Biochemistry 25 : 1525-1528 (1986). [PMID: 3011063]
  4. Fujikawa, K.
    Bovine Hageman factor and its fragments.
    Methods Enzymol. 163 : 54-68 (1988). [PMID: 3237089]
  5. Silverberg, M. and Kaplan, A.P.
    Human Hageman factor and its fragments.
    Methods Enzymol. 163 : 68-80 (1988). [PMID: 3237092]

[EC created 1981]