Table 2.
Limit of detection experiment for individual phosphopeptides in a tryptic digest of α- and β-casein. Values presented are the average spectra count per peptide from two runs for 1 fmol up to 10 pmol. 1 fmol was the lowest amount where at least one phosphopeptide was identified in both replicate MDLC runs.
| Phosphopeptides Identified | Amount Loaded | ||||
|---|---|---|---|---|---|
| 1 fmol | 10 fmol | 100 fmol | 1 pmol | 10 pmol | |
| K.FQS*EEQQQTEDELQDK.I | 1 | 3 | 8 | 61.5 | 91.5 |
| K.YKVPQLEIVPNS*AEER.L | 1 | 1.5 | 4.5 | 30.5 | 52 |
| K.VPQLEIVPNS*AEER.L | 0 | 1.5 | 1 | 5 | 19.5 |
| K.DIGS*ES*TEDQAMEDIK.Q | 0 | 0 | 1 | 5.5 | 21 |
| K.IEKFQS*EEQQQTEDELQDK.I | 0 | 0 | 1 | 1 | 4 |
| K.DIGS*ESTEDQAMEDIK.Q | 0 | 0 | 0 | 1 | 0.5 |
| K.VNELS*KDIGS*ESTEDQAMEDIK.Q | 0 | 0 | 0 | 0.5 | 0.5 |
| K.NMAINPS*KENLCSTFCK.E | 0 | 0 | 0 | 0 | 1 |
| K.TVDMES*TEVFTK.K | 0 | 0 | 0 | 0.5 | 0 |