Brazilian Journal of Medical and Biological Research
On-line version ISSN 1414-431X
YARZABAL, A.; SERRANO, R.L. and PUIG, J.. Modulation of staphylokinase-dependent plasminogen activation by mono- and divalent ions. Braz J Med Biol Res [online]. 1999, vol.32, n.1, pp.39-43. ISSN 1414-431X. http://dx.doi.org/10.1590/S0100-879X1999000100005.
The effect of several ions (Cl-, Na+, K+, Ca2+) on the rate of plasminogen (Pg) activation by recombinant staphylokinase (rSTA) is reported. Both monovalent and divalent ions affect the rate at which Pg is activated by rSTA, in a concentration-dependent manner (range 0-100 mM). In almost all cases, a decrease of the initial velocity of activation was observed. Cl- showed the most striking inhibitory effect at low concentrations (64% at 10 mM). However, in the presence of a fibrin surface, this inhibition was attenuated to 38%. Surprisingly, 10 mM Ca2+ enhanced the Pg activation rate 21% when a polymerized fibrin matrix was present. These data support the idea that ions can modulate the rate of Pg activation through a mechanism that may be associated with changes in the molecular conformation of the zymogen. This effect is strongly dependent on the presence of a fibrin clot.
Keywords : staphylokinase; plasminogen activation; fibrinolysis.