FIGURE 3.

Analysis by mass spectrometry of glutathionylated peptides from the complex I 75-kDa subunit in oxidatively stressed mitochondria. Bovine heart mitochondria were incubated ± diamide; the 75-kDa subunit of complex I was then isolated by BN-PAGE followed by nonreducing SDS-PAGE as described in Fig. 1. After protease digestion, the peptides containing Cys-531 and Cys-704 were analyzed for glutathionylation by MALDI-TOF-MS as described in Table 2. An 8-Da portion of the mass spectra from the analysis of the modified peptides is shown. Data shown for + diamide and - diamide traces are typical MALDI-TOF traces, repeated at least three times with the same result.