Biomedical Engineering Reference
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is outlined in Figure 12.13. Binding of the staphylokinase to plasminogen appears initially to yield
an inactive staphylokinase-plasminogen complex. However, complex formation somehow induces
subsequent proteolytic cleavage of the bound plasminogen to form plasmin, which remains com-
plexed to the staphylokinase. This complex (via the plasmin) then appears to catalyse the conver-
sion of free plasminogen to plasmin, and it may even accelerate the process of conversion of other
staphylokinase-plasminogen complexes into staphylokinase-plasmin complexes. The net effect is
generation of active plasmin, which displays a direct thrombolytic effect by degrading clot-based
fi brin, as described previously (Figure 12.11).
The serum protein
α
2
-antiplasmin can inhibit the activated plasmin-staphylokinase complex.
It appears that the α
2
-antiplasmin can interact with the active plasmin moiety of the complex,
resulting in dissociation of staphylokinase and consequent formation of an inactive plasmin-
α
2
-
antiplasmin complex.
Staphylokinase
Staphylokinase-plasminogen
complex (inactive)
+
Free plasminogen
Staphylokinase-plasmin
complex (active)
Free plasmin
Free plasminogen
Figure 12.13
Schematic representation of the mechanism by which staphylokinase appears to activate the
thrombolytic process via the generation of plasmin. See text for details
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