Title: Characterization of the interaction between plasminogen and staphylokinase
Authors: Lijnen, Roger ×
De Cock, F
Van Hoef, B
Schlott, B
Collen, Desire #
Issue Date: Aug-1994
Publisher: Published by Springer-Verlag on behalf of the Federation of European Biochemical Societies
Series Title: European Journal of Biochemistry vol:224 issue:1 pages:143-9
Abstract: Binding parameters [association (ka) and dissociation (kd) rate constants, and affinity constants (Ka = ka/kd)] for the interaction between recombinant staphylokinase (SakSTAR) and plasmin(ogen) were determined by real-time biospecific interaction analysis. The Ka value for binding of SakSTAR to native human Glu-plasminogen was 0.93 x 10(8) M-1 as compared to 2.0 x 10(8) M-1 and 1.6 x 10(8) M-1, respectively, for the binding to [S741A]recombinant plasminogen or Lys-[S741A]recombinant plasminogen (intact or proteolytically degraded plasminogen with the active site Ser741 replaced by alanine). Binding of SakSTAR to active plasmin or to active-site blocked plasmin occurred with Ka values of 4.0 x 10(8) M-1 and 8.4 x 10(8) M-1, respectively, whereas active-site blocked LMM-plasmin (a plasmin derivative lacking kringles 1-4) and the plasmin B-chain bound with Ka values of 1.0 x 10(8) M-1 and 0.49 x 10(8) M-1, respectively. Lysine-binding site I (a plasminogen derivative consisting of kringles 1-3) and lysine-binding site II (a plasminogen derivative consisting of kringle 4) bound with much lower affinity (Ka values of 1.2 x 10(5) M-1 and 2.9 x 10(5) M-1, respectively). The binding of these plasminogen derivatives to streptokinase occurred with similar relative Ka values. The Ka values for binding of the plasmin-SakSTAR complex to streptokinase and binding of the plasmin-streptokinase complex to SakSTAR, were, respectively, 44-fold and 30-fold lower than the values for free plasmin. The Ka for binding of plasminogen to the inactive mutants [M26R]Sak42D or [M26A]Sak42D (site-specific mutagenesis of Met26 to arginine or alanine) were 10-20-fold lower than that of native staphylokinase. These results indicate that: (a) the affinity of staphylokinase for Glu-plasminogen and Lys-plasminogen is comparable; (b) the active site in the plasmin molecule is not required for binding; (c) kringle structures 1-4 of plasminogen do not contribute significantly to plasminogen binding of staphylokinase; (d) Met26 in staphylokinase is important for its high-affinity binding to plasminogen; (e) the binding sites on plasmin for staphylokinase and streptokinase overlap at least partially.
ISSN: 0014-2956
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Molecular and Vascular Biology
× corresponding author
# (joint) last author

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