抄録
The S-nitrosylation of cysteine thiols participates in the trafficking of nitric oxide (NO) in the intra- and extra-cellular milieu. To establish a mass spectrometric method to detect protein S-nitrosylation, an S-nitrosylated peptide was analyzed using different ionization modes. Electrospray ionization generated intact molecular ions, and in-source fragmentation gave rise to a loss of 30 mass units for the NO moiety. On the other hand, matrix-assisted laser desorption/ionization using an ultraviolet laser produced ions with a mass that was 29 units smaller and represented an unmodified molecule, probably due to reductive cleavage during the ionization process. All of these mass spectrometric features are diagnostic for protein S-nitrosylation.
