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. Transcript analyses revealed that, in addition to the genes encoding enzymes in the glutathione biosynthesis pathway (GSH1 and GSH2), the expression levels of the genes in the cysteine biosynthesis pathway (CYS3 and CYS4) were also significantly higher in the YAP1 over-expressed strain. This suggests that YAP1 over-expression affects glutathione accumulation at both its biosynthesis and substrate availability levels.