prekallikrein:kininogen:C1q binding protein tetramer -> kallikrein:kininogen:C1q binding protein tetramer

Stable Identifier
Reaction [transition]
Homo sapiens
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Prekallikrein in a complex with kininogen and C1q binding protein on the plasma membrane is cleaved to generate active kallikrein, which remains bound to the complex. In the body, this reaction appears to occur on the surfaces of endothelial cells and may require the presence of activated platelets. Recent work indicates that the protease that cleaves prekallikrein under these conditions is prolylcarboxypeptidase. Although this enzyme was originally isolated from lysosomes (Odya et al. 1978; Tan et al. 1993), it is associated with plasma membranes of cultured human endothelial cells in vitro (Moreira et al. 2002; Shariat-Madar et al. 2002), and the purified recombinant enzyme efficiently cleaves prekallikrein (Shariat-Madar et al. 2004). In contrast factor XII, despite its activity on prekallikrein in vitro, appears not to be responsible for prekallikrein activation on the cell surface (Rojkjaer et al. 1998).
Literature References
PubMed ID Title Journal Year
11830581 Identification and characterization of prolylcarboxypeptidase as an endothelial cell prekallikrein activator

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

J Biol Chem 2002
8344943 Sequencing and cloning of human prolylcarboxypeptidase (angiotensinase C). Similarity to both serine carboxypeptidase and prolylendopeptidase families.

Skidgel, RA, Erdos, EG, Morris, PW, Tan, F

J Biol Chem 1993
28321 Purification and properties of prolylcarboxypeptidase (angiotensinase C) from human kidney

Marinkovic, DV, Odya, CE, Erdos, EG, Hammon, KJ, Stewart, TA

J Biol Chem 1978
12123826 Identification of prolylcarboxypeptidase as the cell matrix-associated prekallikrein activator

Schmaier, AH, Shariat-Madar, Z, Moreira, CR, Nader, HB, Motta, G, Mahdi, F

FEBS Lett 2002
14996700 Recombinant prolylcarboxypeptidase activates plasma prekallikrein

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

Blood 2004
Catalyst Activity

serine-type carboxypeptidase activity of prolylcarboxypeptidase dimer [plasma membrane]

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