Staphylokinase
| Staphylokinase ( Staphylococcus aureus ) | ||
|---|---|---|
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Existing structural data: s. UniProt |
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| Mass / length primary structure | 136 amino acids | |
| Cofactor | Plasmin | |
| Identifier | ||
| Gene name (s) | sak | |
| External IDs | ||
The staphylokinase is one of a prophage encoded pathogenicity of Staphylococcus aureus . It is a protein with no enzymatic activity.
Staphylokinase interacts with defensins and with plasminogen . By interacting with defensins, it neutralizes the bacteriocidal effect of these substances and thus represents a means of undermining the innate immune system of the host. The interaction with plasminogen results in active plasmin, a serine protease which dissolves the fibrin into blood clots during fibrinolysis . Staphylokinase is an antagonist of coagulase , which is also produced by S. aureus . The effect of coagulase is similar to that of the body's own thrombin , the most important enzyme in blood clotting , it leads to the polymerisation of fibrinogen to fibrin.
This procedure by S. aureus is very tricky:
- At the beginning of an infection , this bacterium uses the coagulase and, by activating the blood coagulation system, creates a space in which it can multiply undisturbed. This delimitation of the infection site protects it from the attacks of the immune system.
- As soon as it has reached a certain cell density in this niche, it switches on the production of staphylokinase , regulated by quorum sensing depending on the cell density . This dissolves the fibrin structures and blocks part of the immune system. This enables the pathogen to spread further into the surrounding tissue outside of the original site of infection.
In cardiology , streptokinase is used to treat myocardial infarction and severe thrombosis . Clinical tests are currently being carried out to determine whether staphylokinase is also suitable for therapeutic purposes.
literature
- MI Bokarewa, T. Jin, A. Tarkowski: Staphylococcus aureus: staphylokinase. In: Int. J. Biochem. Cell. Biol. 38, 2006, pp. 504-509. PMID 16111912