title: A new vitamin K-dependent protein. A phospholipid-binding zymogen of a serine esterase.
abstract: Conclusive evidence is presented that a recently purified (Stenflo, J. (1976) J. Biol. Chem. 251, 355-363) vitamin K-dependent protein (arbitrarily referred to as Protein C) which is not related to prothrombin, Factors IX or X is also unrelated to Factor VII. It therefore appears to be a new, previously unrecognized vitamin K-dependent protein. In contrast to prothrombin, which binds to negatively charged phospholipid only in the presence of Ca2+ ions, Protein C, like the other vitamin K-dependent proteins, is a precursor of a serine esterase, presumably a protease, but it does not seem to be necessary for blood coagulation. Although the lipid-binding properties of Protein C may suggest that it is associated with membrane structures, its biological function remains unknown.
mesh_terms: D001798:Blood Proteins; D004792:Enzyme Precursors; D004950:Esterases; D007531:Isoflurophate / Q000378:metabolism; D010743:Phospholipids; D011485:Protein Binding; D014357:Trypsin; D014812:Vitamin K / Q000494:pharmacology*
chemical_list: D001798:Blood Proteins; D004792:Enzyme Precursors; D010743:Phospholipids; D014812:Vitamin K; D007531:Isoflurophate; D004950:Esterases; D014357:Trypsin