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Amino acids 225–235 of the protein C serine‐protease domain are important for the interaction with the thrombin‐thrombomodulin complex
Author(s) -
Vincenot A.,
Gaussem P.,
Pittet J.L.,
Debost S.,
Aiach M.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00552-k
Subject(s) - thrombomodulin , thrombin , serine protease , chemistry , amino acid , protease , serine , biochemistry , domain (mathematical analysis) , biology , enzyme , mathematics , platelet , immunology , mathematical analysis
Protein C (PC) is a vitamin K‐dependent zymogen that inactivates factors Va and VIIIa after its activation by thrombin complexed to thrombomodulin. We characterized a monoclonal antibody (mAb) against PC, whose only influence on PC functions was to inhibit PC activation by the thrombin‐thrombomodulin complex. It recognized an epitope in the PC heavy chain, the conformation of which is calcium‐dependent. The mAb did not recognize a natural PC variant that was not activated by the thrombin‐thrombomodulin complex (mutation R229Q) and did recognize a synthetic peptide corresponding to PC amino acids 225–235 in an Elisa assay. The peptide inhibited PC activation by the thrombin‐thrombomodulin complex. These data confirm that the calcium‐binding loop of the serine‐protease domain is involved in the interaction of PC with the thrombin‐thrombomodulin complex.