Glutathione is an important antioxidant molecule in the yeast Saccharomyces cerevisiae

Abstract

The tripeptide gamma-L-glutamyl-L-cystinylglycine (glutathione) is one of the major antioxidant molecules of cells and is thought to play a vital role in buffering the cell against reactive oxygen species and toxic electrophiles. We wished to determine the role of glutathione in the protection of the yeast Saccharomyces cerevisiae against oxidative stress. This study shows that glutathione is an important antioxidant molecule in yeast, with gamma-glutamylcysteine synthetase (gsh1) mutants, deficient in glutathione synthesis, being hypersensitive to H2O2 and superoxide anions in both exponential- and stationary-phase cultures. Despite this, these mutants are still able to induce adaptive stress responses to oxidants.

Amino acid‐dependent regulation of the Saccharomyces cerevisiaeGSH1 gene by hydrogen peroxide

“…Given the importance of glutathione as an antioxidant in eukaryotes and, in particular, in yeast, we wished to investigate the effect of various environmental stresses on the expression of the GSH1 gene (Izawa et al, 1995;Grant et al, 1996b;Stephen and Jamieson, 1996). While we had previously demonstrated that the steady-state levels of the GSH1 mRNA were increased by exposure of cells to oxidants, we needed to demonstrate that this was due to changes in transcription and not through alterations in mRNA stability (Stephen et al, 1995).…”

“…This molecule can act as a free-radical scavenger, with the redox-active sulphydryl group reacting with oxidants to produce oxidized glutathione (GSSG). Previously, ourselves and others have examined the role of glutathione in protecting S. cerevisiae against oxidative stress and have shown that glutathione is an important antioxidant molecule in this organism (Izawa et al, 1995;Grant et al, 1996b;Stephen and Jamieson, 1996). Cellular glutathione levels have been found to be regulated by a gene involved in conferring resistance towards zinc and cadmium (Kobayashi et al, 1996), but the molecular mechanism has not been established.…”

The adaptive response of Saccharomyces cerevisiae to mercury exposure

“…Glutathione-deficient mutants have been shown to be hypersensitive to H 2 O 2 , as well as to the superoxide anion generators plumbagin and menadione (Grant et al, 1996;Stephen and Jamieson, 1996). These mutants are also hypersensitive to the heavy metal cadmium, and the expression of the yeast GSH1 gene, involved in glutathione biosynthesis, has been shown to be inducible by cadmium (Glaeser et al, 1991;Kistler et al, 1986;Stephen and Jamieson, 1997).…”

Effects of Baker’s Yeast Addition on Some Properties and Phytic Acid Content of Tarhana Prepared With Different Cereal and Legume Products

“…Addition of yeast to tarhana caused an increase in antioxidant activity. The antioxidant activity of the bakers' yeast comes from bioactive compounds which can serve as antioxidants, for example glutathione, Maillard reaction products and sulfur-containing amino acids (Sommer, 1996;Stephen and Jamieson, 1996). 25 % barley bran (28.06%) and 50 % rye flour (27.86%) addition in tarhana showed the highest antioxidant activity.…”