The MS scan parameters used are also as follows: Full scan MS1 analysis was performed and was run in positive ion mode with a scan range of m/z 867 -2400. Samples were analysed with an Orbitrap resolution of 15,000 (15K) or 45,000 (45K) at m/z 200 to see if higher resolving power could improve PTM identification. At both resolution settings the RF lens was set at 125%, the normalized AGC target was 50%, the maximum injection time was 200 ms, and the number of microscans was set to 10. Data was collected in profile mode. To assist in desolvation, in-source CID was set to 35 V.