Expression of Recombinant Human Platelet Factor 4 in Escherichia coli and Its Characterization

The polymerase chain reaction (PCR) and recombinant DNA cloning in prokaryotic gene vector were combined to achieve a high expression of recombinant human platelet factor 4 (rhPF4) in Escherichia coli (? coli) . The heparin-sepharose column and a C4 column on reverse phase high per-formance liquid chromatography (RP-HPLC) were used to purify rhPF4 to homogeneity. Purified rhPF4 was biochemically characterized by sodium dodec.vl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot analysis using specific antibody and N-terminal sequence analysis. Bioassay has shown that the rhPF4, like native PF4, has an inhibitory activity on megakaryocytopoiesis in vitro and in vivo in mice. These data demonstrate that the rhPF4 prepared by our methods is highly purified and biologically active and suggest that a potential use of PF4 as a pharmaceutical agent is available.