Plasminogen tissue activator

CH12 RECOMBINANT BLOOD PRODUCTS AND THERAPEUTIC ENZYMES 

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Fig. 2. Outline of possible steps in the recovery and purification sequence for recombinant tissue plasminogen activator derived from recombinant CHO...

Fig. 3. Overview of puriftcation sequence for the nonrecombinant tissue plasminogen activator (t-PA) which also contains urokinase plasminogen activator (u-PA). Serum-free culture conditional media is from normal human ceU line. The temperature for aU. steps, except for size-exclusion chromatography...

Protein G. This vitamin K-dependent glycoproteia serine protease zymogen is produced ia the Hver. It is an anticoagulant with species specificity (19—21). Proteia C is activated to Proteia by thrombomodulin, a proteia that resides on the surface of endothefial cells, plus thrombin ia the presence of calcium. In its active form, Proteia selectively iaactivates, by proteolytic degradation. Factors V, Va, VIII, and Villa. In this reaction the efficiency of Proteia is enhanced by complex formation with free Proteia S. la additioa, Proteia activates tissue plasminogen activator, which... 

Fig. 4. Fibrinolytic system where SCUPA is single-chain urokinase plasminogen activator rTPA is recombinant tissue plasminogen activator APSAC is acylated plasminogen streptokinase activator complex SK is streptokinase and UK is urokinase.

As of early 1992, the market for ceU culture-derived products approached 1 billion per year. The market is expected to grow substantially throughout the 1990s. CeU culture products include erythropoietin, 1991 sales of approximately 400 million, for the treatment of anemia associated with kidney dialysis, and tissue plasminogen activator, 1991 sales approximately 200 million, for treating heart attack victims with blocked arteries (see Cardiovascularagents). 

Tissue Plasminogen Aetivator (tPA). While streptokinase and urokinase can effectively induce clot dissolution in the majority of patients if given early, they lack clot specificity. Treatment with these enzymes results in a systemic lytic state attributable to their degradative action on circulating fibrinogen. Tissue plasminogen activator (tPA) was developed to achieve rapid and specific thrombolysis. 

In a different approach, a TNF fusion protein designated TNF-Selectokine has been described [5]. This TNF prodrug is comprised of a trimeric scFv-TNF fusion protein to which a TNFR fragment has been fused at the C-terminal. A flexible peptide linker between TNF and the blocking receptor domain is comprised of sequences specifically recognized by tumor associated proteases such as tissue plasminogen activator, urokinase type plasminogen activator or... 

TISSUE PLASMINOGEN ACTIVATOR SUPERIOR THERAPY FOR HEART ATTACKS... 

Tissue plasminogen activators Human growth hormone Neuroactive peptides Regulatory peptides Lymphokines Human serum albumin Gamma globulin Antihemophilic factors Monoclonal antibodies... 

Tissue plasminogen activator (alteplase t-PA) is a serine protease that is released into the circulation from vascular endothelium under conditions of injury or... 

Figure 51-7. Scheme of sites of action of streptokinase, tissue plasminogen activator (t-PA), urokinase, plasminogen activator inhibitor, and Kj-antiplasmin (the last two proteins exert inhibitory actions). Streptokinase forms a complex with plasminogen, which exhibits proteolytic activity this cleaves some plasminogen to plasmin, initiating fibrinolysis. 

Table 51-3. Comparison of some properties of streptokinase (SK) and tissue plasminogen activator (t-PA) with regard to their use as thrombolytic agentsJ...

Fibrin is dissolved by plasmin. Plasmin exists as an inactive precursor, plasminogen, which can be activated by tissue plasminogen activator (t-PA). Both t-PA and streptokinase are widely used to treat early thrombosis in the coronary arteries. 

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