Table 2.
Sites of HNE Modification on Endogenous CDK2 Identified by LC-MS/MSa
| peptide | residue modified | XCorr | observed m/z | charge | mass error (ppm) | peptide start–stop | observed spectra |
|---|---|---|---|---|---|---|---|
| LLDVIH*TENK | His71 | 3.58 | 670.3919 | 2 | 4.92 | 66–75 | 3 |
| APEILLGC*K | Cys177 | 2.87 | 1101.6543 | 1 | 3.99 | 170–178 | 5 |
RKO cells were transfected with CDK2-His and treated with HNE. Following isolation of His-tagged proteins and separation by SDS-PAGE, bands corresponding to CDK2-His were excised, subjected to in-gel digestion, and analyzed by tandem mass spectrometry. Modified residues are indicated by an asterisk. Data shown in the table represent the adducted peptides with the lowest mass error.