factor XII -> factor XIIa

Stable Identifier
Reaction [transition]
Homo sapiens
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Cleavage of a single peptide bond converts factor XII to activated factor XII (factor XIIa) (Fujikawa and McMullen 1983; McMullen and Fujikawa 1985). Identification of the catalytic activity or activities responsible for this cleavage has not been straightforward. Studies in vitro have demonstrated the autoactivation of factor XII as well as activation by kallikrein. Both reactions require the presence of negatively charged surfaces and are accelerated in the presence of kininogen (high molecular weight kininogen, HK) (Griffin and Cochrane 1976; Meier et al. 1977; Silverberg et al. 1980). Recent work suggests that factor XII activation in vivo may occur primarily on endothelial cell surfaces and that, as in vitro, association with kininogen may accelerate the reaction (Mahdi et al. 2002; Schmaier 2004), although alternative pathways and alternative mechanisms for associating factor XII with the cell surface have not been excluded (Joseph et al. 2001).

Literature References
PubMed ID Title Journal Year
11204562 Factor XII-dependent contact activation on endothelial cells and binding proteins gC1qR and cytokeratin 1

Ghebrehiwet, B, Joseph, K, Kaplan, AP, Shibayama, Y

Thromb Haemost 2001
14691562 The physiologic basis of assembly and activation of the plasma kallikrein/kinin system

Schmaier, AH

Thromb Haemost 2004
874082 Activation and function of human Hageman factor. The role of high molecular weight kininogen and prekallikrein.

Meier, HL, Pierce, JV, Kaplan, AP, Colman, RW

J Clin Invest 1977
1066663 Mechanisms for the involvement of high molecular weight kininogen in surface-dependent reactions of Hageman factor

Cochrane, CG, Griffin, JH

Proc Natl Acad Sci U S A 1976
6604055 Amino acid sequence of human beta-factor XIIa

Fujikawa, K, McMullen, BA

J Biol Chem 1983
7391081 Autoactivation of human Hageman factor. Demonstration utilizing a synthetic substrate.

Silverberg, M, Dunn, JT, Kaplan, AP, Garen, L

J Biol Chem 1980
11986212 Factor XII interacts with the multiprotein assembly of urokinase plasminogen activator receptor, gC1qR, and cytokeratin 1 on endothelial cell membranes

Schmaier, AH, Shariat-Madar, Z, Figueroa, CD, Mahdi, F

Blood 2002
3886654 Amino acid sequence of the heavy chain of human alpha-factor XIIa (activated Hageman factor)

Fujikawa, K, McMullen, BA

J Biol Chem 1985
Catalyst Activity

serine-type endopeptidase activity of kallikrein:kininogen:C1q binding protein tetramer [plasma membrane]

This event is regulated