title: Generation of the combined prothrombin activation peptide (F1-2) during the clotting of blood and plasma.
abstract: We have investigated the pathway of prothrombin activation in blood and plasma. By means of a rapid purification procedure involving chromatography on DEAE-cellulose and hydroxyapatite, we demonstrated that the major prothrombin fragment in serum is that representing the amino-terminal half of prothrombin (i.e. F1-2). The F1-2 isolated was characterized by its size, amino acid and antigenic compositions, amino-terminal residue, and the peptides (designated F1 and F2, respectively) it yielded upon hydrolysis by thrombin. Measurements by the isotope dilution technique showed that F1-2 could account for the fate of at least 90% of the prothrombin originally present in plasma. By contrast, the serum concentration of the fragment representing the amino-terminal third of prothrombin (viz. F1) was less than 10% that of F1-2. These results demonstrated that the major route of prothrombin conversion in blood or plasma involves the removal of the combined activation fragment (F1-2) as a single peptide.
mesh_terms: D000595:Amino Acid Sequence; D001777:Blood Coagulation; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006868:Hydrolysis; D005779:Immunodiffusion; D010455:Peptides / Q000032:analysis; D010949:Plasma; D011516:Prothrombin / Q000032:analysis; D011865:Radioisotope Dilution Technique; D012995:Solubility; D013053:Spectrophotometry; D014316:Tritium
chemical_list: D010455:Peptides; D014316:Tritium; D011516:Prothrombin