IUBMB Enzyme Nomenclature


Accepted name: coagulation factor XIIa

Reaction: Selective cleavage of ArgIle bonds in factor VII to form factor VIIa and factor XI to form factor XIa

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

Comments: 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: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, PDB, CAS registry number: 75216-42-1


1. Fujikawa, K. and Davie, E.W. Human factor XII (Hageman factor). Methods Enzymol. 80 (1981) 198-211. [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 (1984) 644-650. [PMID: 6370301]

3. Que, B.G. and Davie, E.W. Characterization of a cDNA coding for human factor XII (Hageman factor). Biochemistry 25 (1986) 1525-1528 . [PMID: 3011063]

4. Fujikawa, K. Bovine Hageman factor and its fragments. Methods Enzymol. 163 (1988) 54-68. [PMID: 3237089]

5. Silverberg, M. and Kaplan, A.P. Human Hageman factor and its fragments. Methods Enzymol. 163 (1988) 68-80. [PMID: 3237092]

[EC created 1981]

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