The hypothetical protein YOL049w on the chromosome XV was identified to be the structural gene for glutathione synthetase (GSH2) of Saccharomyces cerevisiae. Translational initiation site was identified by making the GSH2-lacZ fusion. The GSH2 gene contained an open reading frame (1473 bp) with 491 amino acids, and molecular weight of the GSH2 gene product was calculated to be 55,812. Glutathione synthetase activity in transformant carrying the GSH2 gene with multicopy plasmid increased approximately 4-fold. The GSH2 gene was not essential for growth of yeast cell, and glutathione was not detected from the gsh2 disrupter.