A representative selenoprotein peptide MS/MS. Protein- Phospholipid hydroperoxide glutathione peroxidase (Gpx4). Sequence- TDVNYTQLVDLHAR, T1-TMT6plex (229.16293 Da), Charge: +3, Monoisotopic m/z: 625.33752 Da (+0.58 ppm error), MH+ - 1873.99802 Da. XCorr-6.13, Percolator q-Value- 0.0e0, Percolator PEP-5.3e-8. Fragment match tolerance used for search- 0.6 Da. Fragments used for search- b; b-H2O; b-NH3; y; y-H2O; y-NH3.