after 15 min and 30 min of intraperitoneal injection of fitc labeled proteins fig1 the pbmc analyzed by facs showed a gain in fluorescence indicative of the presence of fitc labeled proteins as compared with control animals that received fitc labeled hpsb or unconjugated fitc one of the two parkin recombinant proteins hm 321 psb showed a higher intracellular signal in pbmc the distribution of fitc labeled proteins in different organs in cryosections analyzed by fluorescence microscopy fig9 and 18 similar results the parkin recombinant proteins lacking amtd hp and hpsb showed limited tissue permeability in various organs brain heart lung liver spleen and kidney in contrast amtd 321 enhanced the systemic delivery of parkin recombinant proteins in tissues heart lung liver and kidney to determine the blood brain barrier permeability by using immunohistochemical labeling immunohistochemistry tissues were immunohistochemically processed using anti parkin 1 200 santa cruz biotechnology monoclonal antibodies parkin positive immunoreactivity was observed in brain of the hm 321 psb treated mice but it was not observed in brain of the hpsb treated mice fig2 in the result of western blot parkin antibody positive band was only observed in group administered hm 321 psb recombinant protein fig2 the results have demonstrated that the amtd 321 sd fused parkin recombinant protein could be efficiently delivered to the brain by penetrating the blood brain barrier permeability to determine the protective effect of parkin recombinant protein on the neuronal death caused by the neurotoxin cath a and sh sy5y cells were treated with 6 hydroxydopamine 6 ohda after treatment of 6 ohda these cells were pre treated with parkin recombinant proteins.