Table 1.
Some commonly observed m/z changes due to oxidative modification of Cys9, Met6, or Trp8 within proteins or peptides
| Name | Modification | Δmass | Residue mass |
|---|---|---|---|
| Cys | None | 0 | 103.0092 |
| Cys-disulphide | –H2 | −2.014 | 100.9952 |
| Cys-sulfinamide | +O(–H2) | +13.9809 | 116.9901 |
| Cys-sulfenic acid | +O | +15.9949 | 119.0041 |
| Cys-sulfinic acid | +O2 | +31.9898 | 134.9990 |
| Cys-sulphonic acid | +O3 | +47.9847 | 150.9939 |
| Cys-thiolation | +GSH | 305.6182 | 408.6274 |
| Met | None | 0 | 131.0405 |
| Met-sulphoxide | +O | +15.9949 | 147.0354 |
| Met-sulphone | +O2 | +31.9898 | 163.0303 |
| Trp | None | 0 | 186.0793 |
| Kynurenine | +O (–C) | +3.9949 | 190.0742 |
| 5-Hydroxytryptophan | +O | +15.9949 | 202.0742 |
| Dihydroxytryptophan | +O2 | +31.9898 | 218.0691 |