Expression and purification of human placental growth factor 2 using the Pichia pastoris expression system

To prepare the human placental growth factor 2(PIGF-2), human PIGF-2 gene was cloned into pPIC9K vector to construct the recombinant pPIC9K-PIGF-2 vector. Linearized recombinant pPIC9K-PIGF-2 was transformed into Pichia pastoris by electroporation. YPD-Geneticin plate was used to screen geneticin hyper-resistant colonies. The positive colonies were verified by PCR. Results of SDS-PAGE and Western blot showed that recombinant human PIGF-2 was expressed after being induced by methanol. Using its characteristic heparin binding, recombinant human PIGF-2 was successfully purified by heparin affinity column chromatography.