Figure 2
Two representative MS2 spectra of the peptide IISNASCTTNCLAPLAK of human GAPDH (residues 146-162). Shown are 2 irreversible modifications of the functional Cys152 (A) or His179 (B) in the active site pocket of the enzyme. Modifications were detected through error tolerant searches and Mascot searches including H,W oxidation and C oxidations as variable modifications. (A) Asterisk (*) on C156 indicates carbamidomethylation of unmodified or reversibly modified cysteine residues. In red and blue are highlighted y and b ions, respectively, that arise from the fragmentation of the modified peptides (35 eV CID collision energy).
