Gas-Phase Reactivity of Peptide Thiyl (RS center dot),Perthiyl (RSS center dot), and Sulfinyl (RSO center dot) Radical Ions Formed from Atmospheric Pressure Ion/Radical Reactions

作者：Tan Lei; Xia Yu^*

来源：Journal of the American Society for Mass Spectrometry, 2013, 24(4): 534-542.

DOI：10.1007/s13361-012-0548-y

• Peptide radical ion
• Thiyl radical
• Sulfinyl radical
• Perthiyl radical
• Disulfide bond
• Collision-induced dissociation
• Ion/molecule reactions

In this study, we demonstrated the formation of gas-phase peptide perthiyl (RSS center dot) and thiyl (RS center dot) radical ions besides sulfinyl radical (RSO center dot) ions from atmospheric pressure (AP) ion/radical reactions of peptides containing inter-chain disulfide bonds. The identity of perthiyl radical was verified from characteristic 65 Da (center dot SSH) loss in collision-induced dissociation (CID). This signature loss was further used to assess the purity of peptide perthiyl radical ions formed from AP ion/radical reactions. Ion/molecule reactions combined with CID were carried out to confirm the formation of thiyl radical. Transmission mode ion/molecule reactions in collision cell (q2) were developed as a fast means to estimate the population of peptide thiyl radical ions. The reactivity of peptide thiyl, perthiyl, and sulfinyl radical ions was evaluated based on ion/molecule reactions toward organic disulfides, allyl iodide, organic thiol, and oxygen, which followed in order of thiyl (RS center dot) > perthiyl (RSS center dot) > sulfinyl (RSO center dot). The gas-phase reactivity of these three types of sulfur-based radicals is consistent with literature reports from solution studies.

• 出版日期2013-4