Number of unique phosphorylation sites defined at different site localisation confidence values: ptmRS ≥ 0.99 (green); ptmRS ≥ 0.90 (yellow); ptmRS ≥ 0.75 (red). Light green, yellow or red indicate those sites of pLys or pArg mapped to the extreme peptide C-terminal residue at each ptmRS score cut-off. 