Evaluation of In vivo Bioactivity of a Mutated Streptokinase

Background: Immunogenicity of Streptokinase, as a thrombolytic drug, has limited its clinical use. Elimination of the amino acid residues that are responsible for immunogenicity while don’t affect the bioactivity of streptokinase is worthy. Recently, we modified the streptokinase through the elimination of 42 amino acids from its’ Cterminal and assessed its bioactivity in vitro. In this study, bioactivity of the mutatedstreptokinase determined and compared with those of commercially available streptokinase (Heberkinase) in rabbits with induced blood clot.Materials and Methods: . Recombinant mutated streptokinase was purified and its lipopolysaccharide  contained  remove and evaluated by LAL test. Thrombolytic activity of drug was evaluated by rabbit jugular vein as in vivo thrombosis model. The thrombolytic property of the drug was evaluated with determining of Ddimer in plasma.Results:. The results showed in vivo bioactivity of both truncated and commercial streptokinase (p 0.05). This study showed an important influence of the 42 amino acids of Cterminal in bioactivity of the streptokinase.Conclusion: Clinical use of the rstreptokinase requires more modification to restore its’ activity in vivo. This product may be a promising choice for clinical use after confirmation of its stability and nonimmunogenicity.