Pichia pastoris

About: Pichia pastoris is a research topic. Over the lifetime, 7937 publications have been published within this topic receiving 162645 citations. The topic is also known as: Komagataella pastoris.

Multiple gene copy number enhances insulin precursor secretion in the yeast Pichia pastoris.

Abstract: We have found a direct relationship between protein production in Pichia pastoris and the number of introduced synthetic genes of miniproinsulin (MPI), fused to the Saccharomyces cerevisiae pre-pro alpha factor used as secretion signal, and inserted between the alcohol oxidase 1 (AOX1) promoter and terminator sequences. Two consecutive approaches were followed to increase the number of integrated cassettes: the head-to-tail expression cassette multimerization procedure and re-transformation with a dominant selection marker. This increased expression from 19 to 250 mg l(-1) when about 11 copies have been integrated. Further, the correct position of one of the disulphide bridges of the purified molecule was verified by digestion with Glu-C endoprotease, followed by mass spectrometry of the isolated fragments.

Secretory expression and characterization of insulin in Pichia pastoris

Abstract: The yeasts Pichia pastoris and Saccharomyces cerevisiae have similar overall features regarding the secretory expression of insulin. The S. cerevisiae mating factor alpha (alpha-factor) prepro-leader facilitated the secretion of an insulin precursor, but not proinsulin expressed in P. pastoris. Synthetic prepro-leaders developed for the secretory expression of the insulin precursor in S. cerevisiae also facilitated the secretion of the insulin precursor expressed in P. pastoris. In contrast with S. cerevisiae, only insulin precursor and no unprocessed hyperglycosylated alpha-factor pro-leader/insulin precursor fusion protein was secreted from P. pastoris. A spacer peptide in the fusion protein increased the fermentation yield of the insulin precursor in P. pastoris. A synthetic prepro-leader, but not an alpha-factor prepro-leader lacking N-glycosylation sites, facilitated the secretion of the insulin precursor in P. pastoris. P. pastoris has a capacity for secretory expression of the insulin precursor that is equal to or better than that of S. cerevisiae. Peptide mapping and MS indicated a structure of the insulin precursor expressed in P. pastoris identical with that of human insulin.

Amino acid biosynthesis and metabolic flux profiling of Pichia pastoris.

Abstract: Amino acid biosynthesis and central carbon metabolism of Pichia pastoris were studied using biosynthetically directed fractional (13)C labeling. Cells were grown aerobically in a chemostat culture fed at two dilution rates (0.05 h(-1), 0.16 h(-1)) with glycerol as the sole carbon source. For investigation of amino acid biosynthesis and comparison with glycerol cultivations, cells were also grown at 0.16 h(-1) on glucose. Our results show that, firstly, amino acids are synthesized as in Saccharomyces cerevisiae. Secondly, biosynthesis of mitochondrial pyruvate via the malic enzyme is not registered for any of the three cultivations. Thirdly, transfer of oxaloacetate across the mitochondrial membrane appears bidirectional, with a smaller fraction of cytosolic oxaloacetate stemming from the mitochondrial pool at the higher dilution rate of 0.16 h(-1) (for glucose or glycerol cultivation) when compared to the glycerol cultivation at 0.05 h(-1). Fourthly, the fraction of anaplerotic synthesis of oxaloacetate increases from 33% to 48% when increasing the dilution rate for glycerol supply, while 38% is detected when glucose is fed. Finally, the cultivation on glucose also allowed qualitative comparison with the flux ratio profile previously published for Pichia stipitis and S. cerevisiae grown on glucose in a chemostat culture at a dilution rate of 0.1 h(-1). This provided a first indication that regulation of central carbon metabolism in P. pastoris and S. cerevisiae might be more similar to each other than to P. stipitis.