Table 2.
Quantitative peptidomics of mouse spinal cord: comparison of ECE-2 WT and KO mice
| Precursor | Peptide sequence | Obs. mass |
Theor. mass |
Z | #T | KO : WT Ratio±SD |
MS platform |
|---|---|---|---|---|---|---|---|
| Unknown | 658.18 | 1 | 1 | 0.81±0.09* | LC-ESI-Q-TOF | ||
| Unknown | 768.38 | 2 | 1 | 1.25±0.11* | LC-ESI-Q-TOF | ||
| Unknown | 900.42 | 1 | 1 | 1.74±0.38* | MALDI-TOF | ||
| Unknown | 1174.52 | 3 | 1 | 0.65±0.10** | LC-ESI-Q-TOF | ||
| Unknown | 1174.52 | 4 | 1 | 0.62±0.15* | LC-ESI-Q-TOF | ||
| Unknown | 1174.57 | 1 | 1 | 0.59±0.17* | MALDI-TOF | ||
| Unknown | 1423.34 | 2 | 2 | 0.86±0.02* | LC-ESI-Q-TOF | ||
| Myelin basic protein | N.PVVHFFKNIVTPR.T | 1552.36 | 1552.88 | 2 | 2 | 1.15±0.02** | LC-ESI-Q-TOF |
| Unknown | 1713.48 | 4 | 1 | 0.78±0.04** | LC-ESI-Q-TOF | ||
| Unknown | 1757.78 | 3 | 1 | 0.59±0.17* | LC-ESI-Q-TOF | ||
| Myelin basic protein | F.SWGGRDSRSGSPMARR.# | 1761.47 | 1761.83 | 3 | 1 | 1.24±0.11* | LC-ESI-Q-TOF |
| Unknown | 1777.52 | 4 | 1 | 0.84±0.07* | LC-ESI-Q-TOF | ||
| Unknown | 1777.4 | 3 | 1 | 0.84±0.08* | LC-ESI-Q-TOF | ||
| Unknown | 1990.51 | 3 | 2 | 0.86±0.03** | LC-ESI-Q-TOF | ||
| Unknown | 2104.51 | 3 | 2 | 0.86±0.05* | LC-ESI-Q-TOF | ||
| Unknown | 2298.15 | 1 | 2 | 1.29±0.01** | MALDI-TOF | ||
| Unknown | 2367.60 | 4 | 1 | 0.77±0.11* | LC-ESI-Q-TOF |
Two peptides (MW 1174.52 or 1777.52/1777.4 in bold) were quantified at different charge states (+3 or +4) by LC-ESI-Q-TOF MS, and the results from two charge states are consistent. Peptides were quantified by either LC-ESI-Q-TOF MS or MALDI-TOF MS, with one peptide (MW 1174.52/1174.57 in italic) showing consistent quantitation results between two instruments. Two peptides from myelin basic protein were identified by tandem MS.
(.) indicates a cleavage site;
(#) indicates the end of a precursor sequence;
(_) highlights amino acids W, I and V; Obs. mass, observed monoisotopic mass (after subtraction of the labeling tags); Theor. mass, theoretical monoisotopic mass; Z, charge state; #T, number of tags labeling the peptide; WT, wild type; KO, knockout; SD, standard deviation; n, number of biological replicates observed for a peptide. Student’s t-test was carried out to determine the statistically significant difference between the peptide level of WT and KO mice.
p<0.01,
p<0.05.