Secondary-site binding of Glu-plasmin, Lys-plasmin and miniplasmin to fibrin.
Active-site-inhibited plasmin was prepared by inhibition with d-valyl-l-phenylalanyl-l-lysylchloromethane or by bovine pancreatic trypsin inhibitor (Kunitz inhibitor). Active-site-inhibited Glu-plasmin binds far more strongly to fibrin than Glu-plasminogen [native human plasminogen with N-terminal glutamic acid (residues 1-790)]. This binding is decreased by alpha(2)-plasmin inhibitor and tranexamic acid, and is, in the latter case, related to saturation of a strong lysine-binding site. In contrast, alpha(2)-plasmin inhibitor and tranexamic acid have only weak effects on the binding of Glu-plasminogen to fibrin. This demonstrates that its strong lysine-binding site is of minor importance to its binding to fibrin. Active-site-inhibited Lys-plasmin and Lys-plasminogen (Glu-plasminogen lacking the N-terminal residues Glu(1)-Lys(76), Glu(1)-Arg(67) or Glu(1)-Lys(77))display binding to fibrin similar to that of active-site inhibited Glu-plasmin. In addition, alpha(2)-plasmin inhibitor or tranexamic acid similarly decrease their binding to fibrin. Glu-plasminogen and active-site-inhibited Glu-plasmin have the same gross conformation, and conversion into their respective Lys- forms produces a similar marked change in conformation [Violand, Sodetz & Castellino (1975) Arch. Biochem. Biophys.170, 300-305]. Our results indicate that this change is not essential to the degree of binding to fibrin or to the effect of alpha(2)-plasmin inhibitor and tranexamic acid on this binding. The conversion of miniplasminogen (Glu-plasminogen lacking the N-terminal residues Glu(1)-Val(441)) into active-site-inhibited miniplasmin makes no difference to the degree of binding to fibrin, which is similarly decreased by the addition of tranexamic acid and unaffected by alpha(2)-plasmin inhibitor. Active-site-inhibited Glu-plasmin, Lys-plasmin and miniplasmin have lower fibrin-binding values in a plasma system than in a purified system. Results with miniplasmin(ogen) indicate that plasma proteins other than alpha(2)-plasmin inhibitor and histidine-rich glycoprotein decrease the binding of plasmin(ogen) to fibrin.
D001665:Binding Sites; D004591:Electrophoresis, Polyacrylamide Gel; D005337:Fibrin / Q000378:metabolism*; D005341:Fibrinolysin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010958:Plasminogen / Q000378:metabolism*; D011485:Protein Binding; D014148:Tranexamic Acid / Q000494:pharmacology; D000979:alpha-2-Antiplasmin / Q000494:pharmacology
D005971:Glutamates; D010446:Peptide Fragments; D000979:alpha-2-Antiplasmin; C019493:miniplasmin; D014148:Tranexamic Acid; D005337:Fibrin; D010958:Plasminogen; D005341:Fibrinolysin; D008239:Lysine