Identification of prolylcarboxypeptidase as the cell matrix-associated prekallikrein activator.
Investigations determined that the cell matrix-associated prekallikrein (PK) activator is prolylcarboxypeptidase. PK activation on human umbilical vein endothelial cell (HUVEC) matrix is inhibited by antipain (IC(50)=50 microM) but not anti-factor XIIa antibody, 3 mM benzamidine, 5 mM iodoacetic acid or iodoacetamide, or 3 mM N-ethylmaleimide. Corn trypsin inhibitor (IC(50)=100 nM) or Fmoc-aminoacylpyrrolidine-2-nitrile (IC(50)=100 microM) blocks matrix-associated PK activation. Angiotensin II (IC(50)=100 microM) or bradykinin (IC(50)=3 mM), but not angiotensin 1-7 or bradykinin 1-5, inhibits matrix-associated PK activation. ECV304 cell matrix PK activator also is blocked by 100 microM angiotensin II, 1 microM corn trypsin inhibitor, and 50 microM antipain, but not angiotensin 1-7. 1 mM angiotensin II or 300 microM Fmoc-aminoacylpyrrolidine-2-nitrile indirectly blocks plasminogen activation by inhibiting kallikrein formation for single chain urokinase activation. On immunoblot, prolylcarboxypeptidase antigen is associated with HUVEC matrix. These studies indicate that prolylcarboxypeptidase is the matrix PK activator.
Departmento de Bioquimica, Universidade Federal de Sao Paulo, Sao Paulo, Brazil.
Claudia R
CR
Moreira
Alvin H
AH
Schmaier
Fakhri
F
Mahdi
Guacyara
G
da Motta
Helena B
HB
Nader
Zia
Z
Shariat-Madar
D000804:Angiotensin II / Q000494:pharmacology; D000976:Antipain / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D002268:Carboxypeptidases / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000201:enzymology / Q000378:metabolism*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D010940:Plant Proteins / Q000494:pharmacology; D011288:Prekallikrein / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology
D010940:Plant Proteins; C052160:trypsin inhibitor, Zea mays; D000804:Angiotensin II; D000976:Antipain; D011288:Prekallikrein; D002268:Carboxypeptidases; C022448:lysosomal Pro-X carboxypeptidase; D001920:Bradykinin