Figure 1
Novel AGE modification sites on human cardiac troponin-I (TnI). (A) MS/MS spectrum of trypsin-digested TnI unglycated peptide 193–204 (m/z 645.828). (B) MS/MS spectrum of trypsin-digested TnI peptide 193–204 with CML modification (+29 m/z = +58 Da) of Lys193 (m/z 674.830), confirmed by 4 peptides. (C) MS/MS spectrum of trypsin-digested TnI unglycated peptide 118–131 (m/z 787.444). (D) MS/MS spectrum of trypsin-digested TnI peptide 118–131 with CML modification (+29 m/z = +58 Da) of Lys120 (m/z 816.446), confirmed by 23 peptides. (E) MS/MS spectrum of AspN-digested TnI unglycated peptide 113–126 (m/z 772.931). (F) MS/MS spectrum of AspN-digested TnI peptide 113–126 with CML modification (+29 m/z = +58 Da) of Lys120 (m/z 801.934), confirmed by 7 peptides. (G) MS/MS spectrum of trypsin-digested rat TnI unglycated peptide 119–132 (m/z 787.443) corresponding to human TnI unglycated peptide 118–131. (H) MS/MS spectrum of trypsin-digested rat TnI peptide 119–132 with CML modification (+29 m/z = +58 Da) of Lys121 (m/z 816.449) corresponding to human TnI Lys120. The b-ions denote N-terminal ions and y-ions denote C-terminal ions. CML, N ε-carboxymethyl-lysine.
