Efficient expression and purification of recombinant therapeutic protein candidates, human midkine and pleiotrophin.

Midkine is a heparin-binding growth factor that promotes cell growth, survival, and migration. Externally added midkine prevents ventricular remodeling and improves long-term survival after myocardial infarction in the mouse. Preclinical testing of this protein is in progress.

Secretory expression of human protein in the Yeast Pichia pastoris by controlled fermentor culture.

The heterologous protein expression system of Pichia pastoris is now widely used for expression of many human proteins, because the efficiently expressed proteins will be correctly folded in Pichia pastoris cells and also efficiently secreted from the cells. Recombinant human serum albumin (rHSA) is efficiently secreted from Pichia pastoris. Nowadays, the expression of rHSA exceeds 10g in 1 L fermentor culture broth, and the protein is completely purified.

Efficient production of recombinant human pleiotrophin in yeast, Pichia pastoris.

Approximately 260 mg/l of authentic recombinant human pleiotrophin (rhPTN) was expressed into the medium of high-cell density fermentation using a Pichia pastoris protein expression system. The prepro-sequence of yeast alpha-mating factor was used successfully. The recombinant hPTN was efficiently recovered from the medium by expanded bed adsorption, and purified using successive column chromatography steps.

Characterization of partially truncated human midkine expressed in Pichia pastoris.

Recombinant human midkine (rh-midkine) was expressed under the control of the AOX1 gene promoter in Pichiapastoris. Approximately 640 mg of rh-midkine was secreted into one liter of medium of the high cell-density fermentation. The protein processing of the rh-midkine was done efficiently and correctly in P.