Abstract
The interaction of plasminogen, tissue plasminogen activator (t-PA) and urokinase with a clinical strain of Helicobacter pylori was studied. Plasminogen bound to the surface of H. pylori cells in a concentration-dependent manner and could be activated to the enzymatic form, plasmin, by t-PA. Affinity chromatography assays revealed a plasminogen-binding protein of 58.9 kDa in water extracts of surface proteins. Surface-associated plasmin activity, detected with the chromogenic substrate CBS 00.65, was observed only when plasminogen and an exogenous activator were added to the cell suspension. The two physiologic plasminogen activators, t-PA and urokinase, were also shown to bind to and remain active on the surface of bacterial cells. epsilon-Aminocaproic acid caused partial inhibition of t-PA binding, suggesting that the kringle 2 structure of this activator is involved in the interaction with surface receptors. The activation of plasminogen by t-PA, but not urokinase, strongly depended on the presence of cells and a 25-fold enhancer effect on the initial velocity of activation by t-PA compared to urokinase was established. Furthermore, a relationship between cell concentration and the initial velocity of activation was demonstrated. These findings support the concept that plasminogen activation by t-PA on the bacterial surface is a surface-dependent reaction which offers catalytic advantages.
Original language | English |
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Pages (from-to) | 1015-1021 |
Number of pages | 7 |
Journal | Brazilian Journal of Medical and Biological Research |
Volume | 33 |
Issue number | 9 |
DOIs | |
Publication status | Published - Sept 2000 |
Keywords
- Aminocaproates/metabolism
- Chromatography
- Electrophoresis, Polyacrylamide Gel
- Fibrinolytic Agents/metabolism
- Helicobacter pylori/metabolism
- Humans
- Indicators and Reagents
- Plasminogen Activators/metabolism
- Receptors, Cell Surface/metabolism
- Tissue Plasminogen Activator/metabolism
- Urokinase-Type Plasminogen Activator/metabolism