Engineering of a System for the Production of Mutant Human Alpha-Fetoprotein in the Methylotrophic Yeast Pichia pastoris

A system for the production of mutant recombinant human alpha-fetoprotein (rhAFP0) lacking the glycosylation site has been engineered in the yeast Pichia pastoris . A strain of the methylotrophic yeast Pichia pastoris GS115/pPICZαA/rhAFP0, which produces unglycosylated rhAFP0 and secretes it to the culture medium, has been constructed. Optimization and scale-up of the fermentation technology have resulted in an increase in the rhAFP0 yield to 20 mg/L. A scheme of isolation and purification of biologically active rhAFP0 has been developed. The synthesized protein has the antitumor activity, which is analogous to the activity of natural human embryonic alpha-fetoprotein.