title: Binding properties of 111In-diethylenetriaminepentaacetic acid (DTPA)-fragment E1,2, a fibrin-specific probe, are dependent on use of protecting complex during attachment of DTPA groups.
abstract: Fragments E1 and E2, plasmic degradation products of crosslinked fibrin, bind specifically to polymers of fibrin. A mixture of these fragments, denoted as fragment E1,2, was radiolabeled with 111In after covalently attaching metal chelating groups (diethylenetriaminepentaacetic acid, DTPA) to the fragment, using two approaches. In the first approach, DTPA groups were attached directly to purified fragment E1,2. In the second approach, attachment sites of DTPA groups were directed away from the active region of the molecule by having fragment E1,2 bound in complex, with its active sites protected during the derivatization. Direct attachment of DTPA groups to fragment E1,2 resulted in complete loss of binding to fibrin in vitro. When derivatized in complex, 111In-DTPA-fragment E1,2 retained a higher degree of binding to human fragment DD and human plasma clots in vitro than did radioiodinated fragment E1, even when up to eight DTPA groups were attached per molecule of fragment E1,2.
mesh_terms: D005338:Fibrin Fibrinogen Degradation Products / Q000302:isolation & purification / Q000378:metabolism*; D005341:Fibrinolysin; D006801:Humans; D007204:Indium / Q000378:metabolism*; D007700:Kinetics; D004369:Pentetic Acid / Q000378:metabolism*; D011485:Protein Binding; D011868:Radioisotopes / Q000378:metabolism*
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; D011868:Radioisotopes; C046679:fibrinopeptide E; D007204:Indium; D004369:Pentetic Acid; D005341:Fibrinolysin