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Figure 5 | BMC Microbiology

Figure 5

From: Plasminogen activation by staphylokinase enhances local spreading of S. aureus in skin infections

Figure 5

Species-selectivity and fibrin-specificity of staphylokinase. A. Species-selectivity of staphylokinase (SAK) for human plasminogen (huPlg). Plasmin generation by adding SAK (6.25 nM) to either huPlg (0.25 μM), murine plasminogen (muPlg 0.25 μM), or a mixture of muPlg (0.25 μM) with huPlg (0.05 μM or 20% of the muPlg concentration, comparable to the level of huPlg in murine plasma after adenoviral-mediated huPlg expression). Plasmin generation was quantitated by conversion of the chromogenic substrate S-2403 and assessed in a microtiter plate ELISA reader at 405 nm. Mean and SD from 3 independent experiments. B. Plasmin generation by a preformed equimolar mixture of SAK with huPlg, added to muPlg (0.25 μM), highlighting that low levels of huPlg in a background of muPlg can induce efficient SAK-dependent plasmin generation. Mean and SD from 3 independent experiments. C-D. The complex of SAK with human plasmin (SAK-huPli) is protected from inhibition by alpha-2-antiplasmin (α2AP) in the presence of fibrin analogues. Plasmin generation by SAK (6.25 nM) in a mixture of muPlg (0.25 μM) and huPlg (0.05 μM); with or without α2AP (0.125 μM) and either in the absence or presence of Fg(CNBr) (C. and D. for Fg(CNBr) 10 nM and 100 nM, respectively). Mean and SD from 3 independent experiments.

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