Redox States of Protein Cysteines in Pathways of Protein Turnover and Cytoskeleton Dynamics Are Changed with Aging and Reversed by Slc7a11 Restoration in Mouse Lung Fibroblasts

Figure 3

Representative mass spectrum for determining Cys redox state. Peptides in the mixed samples were ionized and separated by LC-MS/MS. Specific Cys-containing peptides were selected after the first mass spectrometry based on the mass to charge ratio. Those peptides were further fragmented to smaller ions and detected by the second mass spectrometry as shown in the upper panel. The region containing peaks of the reporter ions of the six iodoTMT labels ( 126-131) is shown in the lower panel. The peak intensity ratios of 129/128, 131/130, or 127/126 were defined as redox states for young, old, or old Slc7a11-overexpressing primary mouse lung fibroblasts, respectively.