<p>Glutathione (GSH), the major low-molecular-weight thiol compound in most eukaryotic cells, is normally degraded through the gamma-glutamyl cycle initiated by the action of gamma-glutamyl transpeptidase. A novel pathway for the degradation of GSH that requires the participation of three previously uncharacterised genes has been identified in <taxon tax_id="4932">Saccharomyces cerevisiae</taxon> (Baker's yeast). These genes are DUG1 (YFR044c), DUG2 (YBR281c, <db_xref db="INTERPRO" dbkey="IPR017149"/>), and DUG3 (YNL191w), which contains a glutamine amidotransferase type 2 domain, <db_xref db="INTERPRO" dbkey="IPR000583"/>, and is defective in utilization of glutathione. Although dipeptides and tripeptides with a normal peptide bond, such as cys-gly or glu-cys-gly, can be hydrolysed by the DUG1 protein (a metallopeptidase), the presence of an unusual peptide bond, such as in GSH, requires the participation of the DUG2, which encodes a protein with a metallopeptidase domain and a large WD40 repeat region and DUG3 gene products as well. The DUG3 gene encodes a protein with a glutamine amidotransferase domain. These three proteins form a GSH degradosomal complex [<cite idref="PUB00035950"/>]. </p><p>This entry represents DUG1, which is a metallopeptidases also known as carnosine dipeptidase II that belong to MEROPS peptidase family M20A (glutamate carboxypeptidase family, clan MH).</p>