Objective To express vascular endothelial growth factor(VEGF)189 in Pichia pastoris, purify the expressed product and determine its biological activity in vitro. Methods VEGF183 gene was amplified by overlap PCR using human VEGF183 gene sequence as a template and subcloned to vector pPIC9K. The constructed recombinant plasmid pPIC9K-VEGF189 was transformed to E. coli DH5α for amplification. The plasmid was extracted and linearized with SacⅠ,and transformed to P.pastoris GS115, and high copy clones were scre...