Expression and secretion of natural N-terminal rBPTI with PHOI signal peptide in Pichia pastoris

Objective To express and secrete the natural N-terminal rBPTI with PHOⅠ signal peptide in Pichia pastoris.Methods PHOⅠ/bpti genes were inserted into the eukaryotic expression plasmid.The recombinant plasmid was transformed into the Pichia pastoris(X-33) via electroporation.Results The expression plasmid was constructed to contain correct sequence for PHOⅠ/bpti genes.The rBPTI was expressed and secreted in X-33 .An activity strain was selected with trypsin inhibitor experiment.The expression supernatant was purified with cation exchange chromatography to single peak and SDS-PAGE indicated that the relative molecular mass was 6 500.Conclusion rBPTI with natural N-terminal sequence is successfully expressed in Pichia pastoris with signal peptide of PHOⅠ.