| Autor: |
T J, Ahern, G E, Morris, K M, Barone, P G, Horgan, G A, Timony, L B, Angus, K S, Henson, J B, Stoudemire, P R, Langer-Safer, G R, Larsen |
| Rok vydání: |
1990 |
| Předmět: |
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| Zdroj: |
The Journal of biological chemistry. 265(10) |
| ISSN: |
0021-9258 |
| Popis: |
Recombinant variants of tissue plasminogen activator (t-PA) containing either substitutions or deletions of amino acids within the fibronectin finger-like domain (residues 6-50) were found to exhibit widely varying in vivo clearance profiles in rats and fibrinolytic activity in 125I-fibrin clot lysis assays. Clearance was not significantly affected by changes in the densely charged region of amino acid residues 7-10. Deletions or substitutions of amino acids in the region 14-32 decreased both fibrinolytic activity and the clearance of the enzyme. Modifications within the predicted omega loop of residues 37-41 affected clearance only to a small degree, whereas amino acid alterations in the region of residues 42-49 resulted in as much as a 6-fold decrease in the rate of clearance with only relatively minor decreases in the fibrinolytic activity of the variants. The cumulative results distinguish discrete sections of the NH2-terminal region of the enzyme as determinants of in vivo clearance and fibrinolytic activity of t-PA. In addition, the fibrinolytic activity of a variant containing the substitutions Gln42----Asn, His44----Glu, and Asn117----Gln, when compared with wild-type t-PA in an in vivo rabbit venous clot lysis model, was found to have similar lytic efficacy at approximately one-fourth the dose. We conclude that decreases in the in vivo clearance of t-PA can result in more potent thrombolytic agents in vivo, even though the in vitro fibrinolytic activity of the enzyme may be somewhat impaired. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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