Table 2. List of Detected Histidine Modifications in the ILGGHLDAK Peptidea.
| m/z (no laser/laser) | –10lgP (no laser/laser) | Z (no laser/laser) | RT, min (no laser/laser) | 1/k0 range (no laser/laser) | intensity* (no laser/laser) | contribution to the overall oxidation of the peptide* (no laser/laser), % | modification |
|---|---|---|---|---|---|---|---|
| 469.24 | 34.28/32.24 | 2 | 9.45 | 0.8353–0.8539 | 13,852/22,520 | 1.2/0.6 | +14 Da |
| 900.49 | 53.31 | 1 | 8.59 | 1.4441–1.4619 | -/41,104 | -/1.2 | His → Asn |
| 901.48 | 51.15 | 1 | 9.47 | 1.4377–1.4555 | -/27,527 | -/0.8 | His → Asp |
| 913.48 | 49.49/43.38 | 1 | 6.21 | 1.4477–1.4655 | 8763/11,365 | 0.7/0.3 | –10 Da |
| 928.48 | 52.13 | 1 | 9.23 | 1.4527–1.4705 | -/21,471 | -/0.6 | +5 Da |
| 470.25/939.50 | 35.18/62.14 | 2/1 | 9.06/9.01 | 0.8182–0.8368/1.4833–1.5010 | 6025/505,579 | 0.5/14.5 | +16 Da |
a
1/k0, reduced ion mobility coefficient;12 *, the parameter was calculated using all charge states of respective peptides.