Figure 2.

Identification of persulfidated cysteine(s) in CSE by mass spectrometry. (a) LC-MS/MS analysis of a trypsin-digested peptide containing the persulfidated Cys109 residue derivatized with iodoacetamide with an additional mass increment of 88.9935 Da. (b) A trypsin-digested peptide containing the persulfidated Cys137 residue (mass increment of 88.9936 Da) was identified. (c) A trypsin-digested peptide containing the persulfidated Cys172 residue (mass increment of 88.9935 Da) was identified.