YAP1 over-expression in Saccharomyces cerevisiae enhances glutathione accumulation at its biosynthesis and substrate availability levels.

Microbiological production of glutathione using genetically engineered yeast strains has a potential to satisfy the increasing industrial demand of this tripeptide. In the present work accumulation of glutathione in response to YAP1 over-expression in Saccharomyces cerevisiae was studied. The over-expression resulted in intracellular glutathione level over two times higher than in the parent strain.

Metabolic changes underlying the higher accumulation of glutathione in Saccharomyces cerevisiae mutants.

Molecular mechanisms leading to glutathione (GSH) over-accumulation in a Saccharomyces cerevisiae strain produced by UV irradiation-induced random mutagenesis were studied. The mutant accumulated GSH but also cysteine and γ-glutamylcysteine in concentrations that were several fold higher than in its wild-type parent strain under all studied cultivation conditions (chemostat, fed-batch, and turbidostat). Transcript analyses along with shotgun proteome quantification indicated a difference in the expression of a number of genes and proteins, the most pronounced of which were several fold higher expression of CYS3, but also that of GSH1 and its transcriptional activator YAP1.

Glutathione accumulation in ethanol-stat fed-batch culture of Saccharomyces cerevisiae with a switch to cysteine feeding.

Shot-wise supplementation of cysteine to a yeast culture is a common means of promoting glutathione (GSH) production. In the present work, we study the accumulation kinetics of cysteine, gamma-glutamylcysteine, and GSH and the expression of genes involved in GSH and sulfur metabolism in ethanol-stat fed-batch cultures as a result of switching to a medium enriched with cysteine and glycine. Supplementation in this fashion resulted in a rapid but short-term increase in the rate of GSH synthesis, while the expression of GSH1 decreased.

The response of the yeast Saccharomyces cerevisiae to sudden vs. gradual changes in environmental stress monitored by expression of the stress response protein Hsp12p.

The response of the yeast Saccharomyces cerevisiae to sudden vs. gradual changes in different environmental stress conditions during both respiratory growth and aerobic fermentative growth in the presence of excess glucose was investigated by monitoring the level and rate of expression of the stress response protein Hsp12p using the fluorescent fusion construct Hsp12p-Gfp2p. The initial expression level and the rate of Hsp12p synthesis was significantly greater under glucose-limited conditions in the chemostat (D<0.