title: Activation of bovine factor VII (proconvertin) by factor XIIa (activated Hageman factor).
abstract: Bovine factor VII (proconvertin) is a plasma glycoprotein that participates in the extrinsic pathway of blood coagulation. It has a molecular weight of 45 500 and is composed of a single polypeptide chain with an amino-terminal alanine residue. Factor VII is readily converted to factor VIIa by factor XIIa (activated Hageman factor) employing an enzyme to substrate weight ratio of 1:50. Factor VIIa is composed of a light and a heavy chain held together by a disulfide bond(s). The heavy chain, which is formed from the carboxyl-terminal region of the precursor, contains an amino-terminal sequence of Ile-Val-Gly-Gly-. The heavy chain also contains the active-site sequence of -Phe-Cys-Ala-Gly-Tyr-Thr-Asp-Gly-Thr-Lys-Asp-Ala-Cys-Lys-Gly-Asp-Ser-Gly-Gly-Pro-His-. This sequence is homologous with the active-site region of a number of plasma serine proteases. These data indicate that factor VII is a typical precursor of a serine protease which is converted to an enzyme by factor XIIa by the cleavage of a single, internal peptide bond.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D004789:Enzyme Activation; D005167:Factor VII / Q000378:metabolism; D005174:Factor XII / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D011487:Protein Conformation
chemical_list: D010446:Peptide Fragments; D005167:Factor VII; D005174:Factor XII