TABLE 1 .
PkaC1 phosphorylation sites identified by LC-MS/MS analysis
| Peptide sequencea | Phosphorylated residue | m/z | Charge | Mass error (ppm) | Mascot ion scoreb | Ascore localization probabilityc |
|---|---|---|---|---|---|---|
| GKY[pS]LDDFTIQR | S175 | 761.8521 | 2 | 2.11 | 49.5 | 99.99 |
| EVPDI[pT]WTLCGTPDYLAP | T331 | 919.7646 | 3 | 2.29 | 52.8 | 95.22 |
| EVPDITW[pT]LCGTPDYLAP | T333 | 1,379.1445 | 2 | 1.1 | 73.9 | 95.74 |
| EVPDITWTLCG[pT]PDYLAP | T337 | 919.765 | 3 | 2.75 | 57.1 | 99.36 |
a
“[pS]” or “[pT]” indicates a phosphorylated residue.
b
Mascot identity score of >41 indicates identity or extensive homology (P < 0.05).
c
Probability of phosphorylated residue localization based on Ascore algorithm. Peptides contained uniquely identified phosphorylation residues or combinations of phosphorylation residues. Due to the proximity of multiple phosphorylatable residues within these peptides, mass spectra from each identification were submitted to an independent algorithm (Ascore) which assigns confidences to the localization of each phosphorylation.