Differences in the Reactivities of Human Urokinase and the Porcine Tissue Plasminogen Activator

Thorsen, Sixtus; Astrup, Tage

doi:10.1159/000214148

Cited by 13 publications

(15 citation statements)

References 29 publications

(36 reference statements)

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“…All of these forms not only bound to fibrin, but also appeared to require fibrin for their activity. This fibrin cofactor requirement is the primary functional distinction between tissue-type and urinary PAs (6). The Mr 52,000 form resembled urokinase in that it showed no association with fibrin.…”

Section: Discussionmentioning

confidence: 92%

Cultured bovine endothelial cells produce both urokinase and tissue-type plasminogen activators.

Levin¹,

Loskutoff²

1982

The Journal of Cell Biology

370

112

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Cell extracts and conditioned media (CM) from cultured bovine aortic endothelial cells (BAEs) were fractionated by PAGE in the presence SDS, and plasminogen activator (PA) activity was localized by fibrin autography. Multiple molecular weight forms of PA were detected in both preparations. Cell-associated PAs had Mr of 48,000, 74,000, and 100,000 while secreted PAs showed Mr of 52,000, 74,000, and 100,000. A broad zone of activity (Mr 80,000-100,000) also was present in both cellular fractions. In addition, PAs of Mr 41,000 and 30,000 appeared upon prolonged incubation or repeated freezing and thawing of the samples, and probably represent degradation products of higher molecular weight forms. This complex lysis pattern was not observed when CM was subjected to isoelectric focusing. Instead, only two classes of activator were resolved, one at pH 8.5, the other at 7.6. Analysis of focused samples by SDS PAGE revealed that the activity at pH 8.5 resulted exclusively from the Mr 52,000 form; all other forms were recovered at pH 7.6. The activity of the Mr 52,000 form was neutralized by anti-urokinase IgG but was not affected by antitissue activator IgG indicating that it is a urokinaselike PA. The activities of the Mr 74,000-100,000 forms were not affected by anti-urokinase. They were blocked by antitissue activator suggesting that all the forms in this group were tissue-type PAs. The multiple forms of PA were differentially sensitive to inactivation by diisopropylfluorophosphate (DFP). Treatment of CM with 10 mM DFP for 2 h at 37 degrees C only partially inhibited the 52,000-dalton form. However, it completely inactivated the 74,000-dalton partially inhibited the 52,000-dalton form. However, it completely inactivated the 74,000-dalton PA. The activity of the Mr 100,000 form was not affected by this treatment, or by treatment with 40 mM DFP. Thus, cultured BAEs produce multiple, immunologically distinct forms of PA which differ in size, charge, and sensitivity to DFP. These forms include both urokinaselike and tissue-activator-like PAs. The possibility that one of these forms is a zymogen is discussed.

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Section: Discussionmentioning

confidence: 92%

Cultured bovine endothelial cells produce both urokinase and tissue-type plasminogen activators.

Levin¹,

Loskutoff²

1982

The Journal of Cell Biology

370

112

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“…Enhancement of the fibrinolysis by the acid occurs under suitable conditions. The source, preparation and concentration of fibrinogen are important for the shape of the pattern [1], Clinically. EACA.…”

mentioning

confidence: 99%

Effect of EACA, PAMBA, AMCA and AMBOCA on Fibrinolysis Induced by Streptokinase, Urokinase and Tissue Activator

Westlund¹,

Lundén²,

Wallén³

1982

Pathophysiol Haemos Thromb

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A study is presented in which the inhibiting effects of EACA, PAMBA, AMCA and AMBOCA on fibrinolysis induced by three activators have been compared by a clot lysis method. The order of inhibitory potency was AMBOCA > AMCA > PAMBA > EACA. The activity ratios obtained were found to be influenced by the level of inhibition. At low levels of inhibition the differences between the inhibitory activities are usually more pronounced than at high levels. The degree of inhibition is dependent on the fibrinolytic activator used. The order of sensitivity to the inhibitors was, within the analytical conditions used, found to be: tissue activator > streptokinase > urokinase. The results are discussed in comparison to the different activity ratios reported by others.

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“…Thus, the curves obtained with urokinase deflect down ward at the lower concentrations, probably in part because this activator has a lower affin ity to fibrin than the tissue activator [40]. Urokinase and the tissue plasminogen activa tor also respond differently to changes in the composition of the substrate [41].…”

Section: Analytical Variability O F the Assay Of Tissue Plasminogen Amentioning

confidence: 98%

A Study of the Fibrin Plate Assay of Fibrinolytic Agents

Jespersen¹,

Astrup²

1983

Pathophysiol Haemos Thromb

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The reproducibility, precision and required conditions of the fibrin plate method for determination of fibrinolytic agents are described in detail. Under optimal conditions the assay is a sensitive and precise method for the quantitative determination of fibrinolytic agents. Thus, with a tissue plasminogen activator preparation its sensitivity is approximately 0.02 CTA urokinase units/ml, and dilutions yielded a curve with a slope (double-logarithmic) with a day-to-day mean of 0.53 with a coefficient of variation of 5.1%.

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Differences in the Reactivities of Human Urokinase and the Porcine Tissue Plasminogen Activator

Cited by 13 publications

References 29 publications

Cultured bovine endothelial cells produce both urokinase and tissue-type plasminogen activators.

Cultured bovine endothelial cells produce both urokinase and tissue-type plasminogen activators.

Effect of EACA, PAMBA, AMCA and AMBOCA on Fibrinolysis Induced by Streptokinase, Urokinase and Tissue Activator

A Study of the Fibrin Plate Assay of Fibrinolytic Agents

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