title: Fibrinogen coagulation without thrombin: reaction with vitamin C and copper(II).
abstract: We describe a novel method for inducing fibrinogen derived clots. The addition of vitamin C (0.1-1 mM) to a solution of fibrinogen (1 mg/ml) and Cu(II) (20-150 microM) results in protein coming out of solution. This phenomenon can be "read" by fibrometers as "clotting time". The reaction requires Cu(II) and can be prevented by a chelating agent, such as citrate, as well by a hydroxyl radical scavenger, such as mannitol. The insoluble protein, called "neofibe", is soluble in 4 M urea and 2% SDS. Isoelectric focusing and SDS-electrophoretic comparison of native fibrinogen with neofibe reveal molecular modifications of the starting protein. This reaction is an interesting example of a free radical mediated transformation of soluble protein into insoluble material. Some findings on the connection between hemostasis, vitamin C and Cu(II) are discussed.
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology*; D003300:Copper / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D013917:Thrombin / Q000378:metabolism*; D014914:Whole Blood Coagulation Time
chemical_list: D003300:Copper; D005340:Fibrinogen; D013917:Thrombin; D001205:Ascorbic Acid