GLUTATHIONE IS AN IMPORTANT ANTIOXIDANT MOLECULE IN THE YEAST SACCHAROMYCES-CEREVISIAE

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 t oxic 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) muta nts, deficient in glutathione synthesis, being hypersensitive to H2O2 and superoxide anions in both exponential- and stationary-phase cultur es. Despite this, these mutants are still able to induce adaptive stre ss responses to oxidants.