evaluation of in vivo bioactivity of a mutated streptokinase

background : immunogenicity of streptokinase (stk), as a thrombolytic drug, have limited its clinical use. elimination of the amino acid residues that are responsible for immunogenicity while don’t affect the bioactivity of stk is worthy. recently, we modified the stk through elimination of 42 amino acids from its’ c-terminal and assessed its bioactivity in vitro . objective : in this study, bioactivity of the mutated-stk determined and compared with those of commercially available streptokinase (heberkinase) in rabbits with induced blood clot. results :the thrombolytic property of the drugs evaluated with determining of d-dimer in plasma. the results showed in vivo bioactivity of both truncated and commercial stks (p < 0.05). this study showed an important influence of the 42 amino acids of c-terminal in bioactivity of the stk. conclusion: clinical use of the rstk 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 non-immunogenicity.