Sequence Confirmation of Cyclic Thioether Bridged Peptides by Nanospray CID MS/MS.

摘要

This technique is useful for small, low charge thioether bridged peptides where ECD is not practical. The oxidation reaction is fast and relatively clean. A usable amount of the oxidized form is generated in a few minutes. The reaction does not need to be run to completion, which would risk oxidizing other amino acids. The hydrogen peroxide does not add any background ions or interfere with ionization. The isotope envelopes of the oxidized and unoxidized peptides do not overlap, so the oxidized peptide can be isolated in the mass spectrometer, eliminating the need for an offline separation.