title: Modulation of staphylokinase-dependent plasminogen activation by mono- and divalent ions.
abstract: 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.
authors.affiliation: Laboratorio de Biologia y Medicina Experimental, Facultad de Ciencias, Universidad de Los Andes, Merida, Venezuela. yluis@ing.ula.ve
authors.forename: A
authors.initials: A
authors.lastname: Yarzábal
authors.forename: R L
authors.initials: RL
authors.lastname: Serrano
authors.forename: J
authors.initials: J
authors.lastname: Puig
mesh_terms: D004789:Enzyme Activation / Q000187:drug effects; D005343:Fibrinolytic Agents / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007477:Ions; D008666:Metalloendopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D010958:Plasminogen / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005343:Fibrinolytic Agents; D007477:Ions; D010958:Plasminogen; D008666:Metalloendopeptidases; C022653:auR protein, Staphylococcus aureus