Tritiated Bovine Fibrinogen Labelled in Fibrinopeptide a Region

摘要

The method is described for labelling of bovine fibrinogen with exp 3 H-AcOAc. Preparations labelled at pH 7.8 with 10 to 40 molar excess of exp 3 H-AcOAc were found to contain 8 to 13 moles of acetyl residues per mole of fibrinogen. The content of clottable protein and UV spectra were unchanged as compared with control unlabelled preprations. The rate of clotting with thrombin was only slightly affected. The investigations on distribution of exp 3 H in products of proteolysis of exp 3 H-fibrinogen by thrombin and plasmin demonstrated a preferential labelling of fibrinopeptide A, absence of radioactive tracer in fibrinopeptide B, significantly higher specific radioactivity of fragment E than that of fragment D. Incorporation of the label into fibrinopeptide A opens the possibility for application of exp 3 H-fibrinogen as a convenient substrate for selective investigations on the enzymatic phase of clotting. (Atomindex citation 08:337083)