Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.5 (thrombin)
 33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We attempted to construct a new recombinant protein characterized by fibrin-specific properties of plasminogen activation combined with antithrombin and antiplatelet activities. To the C-terminal part of recombinant staphylokinase (r-SAK), which is a promising profibrinolytic agent, we assembled: (i) the Kringle 2 domain (K2) of tissue-type plasminogen activator (t-PA), containing a fibrin-specific binding site, (ii) the RGD sequence (Arg-Gly-Asp) for the prevention of platelet aggregation and (iii) the antithrombotic agent - hirudin. The cDNA for hybrid protein SAK-RGD-K2-Hir was cloned into pESP-3 yeast protein expression vector. The introduction of K2 t-PA, RGD sequence and hirudin into r-SAK molecule did not alter the SAK activity. The plasminogen activation rate (determined by K(M) and K(cat)) of SAK-RGD-K2-Hir was not significantly different from that of r-SAK. Affinity and binding strength of the recombinant protein to fibrin immobilized on the biosensor were higher than to r-SAK. We observed a higher clot lysis potency of SAK-RGD-K2-Hir as evidenced by a faster and more profound lysis of 125I-labeled human fibrin clots. The potency of thrombin inhibition by the hirudin part of the recombinant fusion protein SAK-RGD-K2-Hir was the same as that of r-Hir alone. In conclusion, the results of the in vitro study suggest that the SAK-RGD-K2-Hir construct can be a more potent and faster-acting thrombolytic agent with antithrombin and antiplatelet properties compared with standard r-SAK.
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PMID:A new recombinant thrombolytic and antithrombotic agent with higher fibrin affinity--a staphylokinase variant. I. In vitro study. 1615 47

In the quest of a therapeutically improved thrombolytic drug, we designed and expressed a Staphylokinase based, recombinant fusion protein with fibrin specific clot lysis and anti-thrombin activities derived from human thrombomodulin, a transmembrane glycoprotein with anticoagulant properties, known to form a complex with thrombin and then activating Protein C. The fusion construct was expressed in the yeast Pichia pastoris for cost effective and facile production. The purified construct had comparable plasminogen activation and clot lysis capability as compared to native SAK in that it showed plasmin dependent Plasminogen activation, but exhibited significantly lower fibrinogenolysis (an indicator of fibrin-specific action) even at much higher doses than SAK. In addition, its successful activation of the thrombin-mediated Protein C anticoagulant pathway was reflected in increased in vitro plasma clotting time, as well as inhibition of clot bound thrombin, which led to nearly 15-25% lesser re-formation of fibrin clots after initial successful clot lysis in a specially designed in vitro assay for re-occlusion. Thus, this novel chimeric protein could be of high therapeutic potential as a thrombolytic drug with enhanced fibrin specific clot dissolving properties along with lower bleeding and re-thrombosis complications- a dire need today, especially in the treatment of thrombotic strokes.
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PMID:Design of a thrombin inhibitory staphylokinase based plasminogen activator with anti-reocclusion potential. 3173 7