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Identification of oxidized methionine in peptides.

Rapid communications in mass spectrometry : RCM (1996-01-01)
F M Lagerwerf, M van de Weert, W Heerma, J Haverkamp
ABSTRACT

The positive- and negative-ion collision-induced dissociation spectra of peptides containing methionine, methionine sulphoxide and methionine sulphone have been studied. Characteristic fragmentations were identified and evaluated as possible indicators for the presence of oxidized methionine residues in peptides. It was found that the elimination of CH3SOH (-64 u) from [M + H]+ is unique for peptides that contain methionine sulphoxide. Sequence ions containing the oxidized methionine undergo the same elimination, allowing unambiguous sequence determination. Methionine sulphone exhibits an analogous elimination of CH3SO2H (-80 u) from the protonated molecule, but not from sequence ions.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
DL-Methionine sulfone, ≥99.0% (NT)
Sigma-Aldrich
L-Methionine sulfone