title: Location of the binding site "b" for lateral polymerization of fibrin.
abstract: We examined the location of the binding site "b" for lateral polymerization of fibrin using two fractions of normal human fibrinogen, a high-molecular weight fraction (so-called normal fibrinogen) and a low-molecular weight fraction which lacks the C-terminal half of one of its two A alpha chains, and Gly-His-Arg-Pro, a synthetic peptide that corresponds to the N-terminal sequence of human fibrin beta chain and binds specifically to the site "b". The amounts of the synthetic peptide bound to each of the low- and high-molecular weight fractions were 1 mol/mol and 2 mol/mol, respectively. The peptide delayed the clotting of fibrinogen by blocking the site "b", but did not inhibit thrombin at all. In the presence of the peptide, the high-molecular weight fraction did not form a normal coarse clot but a fine clot which was identical to that produced by the low-molecular weight fraction. The identity of the two clots was judged from four different points: morphology, turbidity, elasticity and clotting velocity of fibrin. The results suggest that the site "b" is located within the portion of the fibrinogen molecule present in the high-molecular weight fraction, but not in the low-molecular weight fraction and that the site "b" plays an essential role in the lateral polymerization of fibrin.
authors.affiliation: Department of Physiology, Fujita Health University School of Medicine, Aichi, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hasegawa
authors.forename: S
authors.initials: S
authors.lastname: Sasaki
mesh_terms: D001665:Binding Sites; D004548:Elasticity; D005337:Fibrin / Q000378:metabolism* / Q000648:ultrastructure; D005340:Fibrinogen / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D066298:In Vitro Techniques; D008970:Molecular Weight; D011108:Polymers; D013918:Thrombin Time
chemical_list: D011108:Polymers; D005337:Fibrin; D005340:Fibrinogen