Table 1. Identifying phosphorylation sites of GST-p12 precipitated from 293T cells using nano LC–MS/MS.
| Phosphorylated peptides | Missed cleavages | 1Phosphorylated residues (>50% probability) | 2Fraction of phosphorylated peptides | |
|---|---|---|---|---|
| 3R1 | R2 | |||
| DGNGGEATPAGEAPDPSPMASR (p12 aa 45–66) | 0 | T52 | 0.13 | 0.04 |
| S61 | 0.36 | 0.49 | ||
| S65 | 0.01 | 0.07 | ||
| DPRPPPSDRDGNGGEATPAGEAPDPSPMASR (p12 aa 36–66) | 1 | T52 | ND | ND |
| S61 | 0.47 | 0.52 | ||
| S65 | ND | ND | ||
| EPPVADSTTSQAFEFGGR (p12 aa 72–84+ linker) | 0 | S78 | 0.03 | 0.03 |
| T80 | 0.01 | ND | ||
| S81 | 0.03 | 0.01 | ||
| REPPVADSTTSQAFEFGGR (p12 aa 71–84+ linker) | 1 | S78 | ND | ND |
| T80 | 0.04 | ND | ||
| S81 | 0.10 | ND | ||
1 A peptide was counted as being phosphorylated at a specific residue if its phosphoRS site probability was >50%.
2 For each tryptic peptide, the phosphorylation level at a particular site was estimated by dividing the phosphorylated peptide count by the total peptide count.
3 R1 and R2 are biological replicates.