title: Contribution of Pro212-Ile276 sequence of human protein C to its anticoagulant and profibrinolytic activity.
abstract: Activated protein C exhibits strong anticoagulant and profibrinolytic properties. The Pro212-Ile276 fragment of a heavy chain of the protein molecule is located in the nearest neighborhood of the catalytic domain. It was found that polyclonal antibodies against this fragment recognize the sequence in the native molecule. To determine the contribution of the fragment in the anticoagulant and profibrinolytic activities of the enzyme, competitive inhibition analyses were performed. We found that amidolytic activity of the enzyme was inhibited by the recombinant Pro212-Ile276 fragment in a dose-dependent manner. Also, the fusion protein prolonged the time of clot lysis in a micro-clot lysis assay. The presence of the recombinant protein fragment did not influence the reaction of activated protein C with factor Va, neither the reaction of the enzyme with its specific inhibitor. We conclude, that Pro212-Ile276 region of protein C can not be identified with the binding pocket of the enzyme, but might be a binding site for small, low molecular weight substrates like chromogenic substrate.
authors.affiliation: Microbiology and Virology Centre, Polish Academy of Sciences, Lodz. ifijalko@wirus.cmiwpan.lodz.pl
authors.forename: I
authors.initials: I
authors.lastname: Fijalkowska
authors.forename: J
authors.initials: J
authors.lastname: Jastrzebowska
authors.forename: C S
authors.initials: CS
authors.lastname: Cierniewski
mesh_terms: D000925:Anticoagulants; D001667:Binding, Competitive; D001777:Blood Coagulation / Q000187:drug effects; D001780:Blood Coagulation Tests; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D015943:Factor Va / Q000378:metabolism; D005342:Fibrinolysis / Q000502:physiology*; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D010446:Peptide Fragments / Q000494:pharmacology / Q000502:physiology*; D011486:Protein C / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D011993:Recombinant Fusion Proteins
chemical_list: D000925:Anticoagulants; D010446:Peptide Fragments; D011486:Protein C; D011993:Recombinant Fusion Proteins; D015943:Factor Va; D006493:Heparin