Table 1.
Liquid chromatography conditions and mass spectrometry results. The pH of the aqueous phase was adjusted in intervals of 1 pH unit from pH 8.0 to pH 2.5, the latter being our normal operating condition. A control (no ATP) and experimental (with ATP) auto-kinase reaction were performed on NM23-H1. Shown are conditions, percent sequence coverage of the protein, number of unique peptides corresponding to NM23-H1 and presence of detectable histidine phosphorylation (indicated as detected or not-detected in the “pHis column”, with D indicating the absence of pHis and ND indicating the pHis was not detected).
| Sample | pH Solvent A | % Coverage | #Peptides | P-His |
|---|---|---|---|---|
| Control | 8 | 62.7 | 17 | ND |
| + ATP | 8 | 70.9 | 11 | ND |
| Control | 7 | 72.8 | 11 | ND |
| + ATP | 7 | 70.9 | 18 | ND |
| Control | 6 | 70.9 | 18 | ND |
| + ATP | 6 | 77.2 | 21 | D |
| Control | 5 | 91.8 | 23 | ND |
| + ATP | 5 | 76.6 | 20 | D |
| Control | 4 | 76.6 | 27 | ND |
| + ATP | 4 | 76.6 | 26 | ND |
| Control | 3 | 95.6 | 22 | ND |
| + ATP | 3 | 67.7 | 24 | ND |
| Control | 2.5 | 95.6 | 29 | ND |
| + ATP | 2.5 | 95.6 | 21 | ND |