E bradykinin. The nonapeptide has a very short half-life (a matter of seconds) and exhibits its functions via the B1 and B2 receptors (3). Generating other mediators such as nitric oxide, prostaglandins, and leukotrienes, bradykinin is involved in the regulation of blood pressure, the induction of fever and pain, vascular leakage, and the chemotaxis of immune cells (4). In addition, further proces

N activator streptokinase might contribute to contact system activation by S. pyogenes. Here, we report that the human contact system is activated by the action of streptokinase. The role of secreted and surfacebound streptokinase in this process was investigated by comparing an M49 S. pyogenes wild-type strain with its isogenic ska mutant, which is unable to trigger plasmin activity in human plas

The GAS M49 591 chromosomal background was generated previously by insertional inactivation of the ska gene (16). The construction of the epf, emm49, and prtF2 mutant strains from GAS M49 591 has been described previously (17?0). The GAS strains were cultured in Todd-Hewitt broth (THB; Invitrogen) at 37 under a 5 CO2 and 20 O2 atmosphere. Materials. Pooled normal plasma and plasma deficient in

N activator streptokinase might contribute to contact system activation by S. pyogenes. Here, we report that the human contact system is activated by the action of streptokinase. The role of secreted and surfacebound streptokinase in this process was investigated by comparing an M49 S. pyogenes wild-type strain with its isogenic ska mutant, which is unable to trigger plasmin activity in human plas

T virulence mechanism and function to a growing list of streptokinase activities.MATERIALS AND METHODSBacterial strains and culture conditions. GAS serotype M49 strain 591 was obtained from R. L ticken (Aachen, Germany). GAS M1 strain 90226 was obtained from the World Health Organization Center for Reference and Research on Streptococci at the University of Minnesota. It was originally isolated fr

N activator streptokinase might contribute to contact system activation by S. pyogenes. Here, we report that the human contact system is activated by the action of streptokinase. The role of secreted and surfacebound streptokinase in this process was investigated by comparing an M49 S. pyogenes wild-type strain with its isogenic ska mutant, which is unable to trigger plasmin activity in human plas

System comprises four plasma proteins, circulating as zymogens in the bloodstream or being assembled on various cell types: the serine proteases factor XII (FXII), factor XI (FXI), and prekallikrein (PKK) and the nonenzymatic cofactor high-molecularweight kininogen (HK). The latter forms equimolar complexes with plasma kallikrein (PK) or FXI. The cascade is initiated upon contact to a negatively c

Ct on the ability of tAg to bind p107 (Fig. 4) or p130 (data not shown). It is likely that both LxCxE motifs contribute to Rb binding, perhaps redundantly, and that to abolish binding activity, double mutants will have to be createdJCV Small t Protein Functionsand tested. It is also possible that neither LxCxE motif is required for Rb binding, as a number of cellular proteins lacking this sequence