EBIProteins Get Proteomics Ptm

Get post-translational modification (PTM) evidence from mass spectrometry proteomics for a protein from the EBI Proteins API. Returns experimentally detected PTMs (phosphorylation, acetylation, ubiquitination, etc.) with evidence from PeptideAtlas, ProteomicsDB, MaxQB, and EPD proteomics repositories. Shows modification positions, types, and detection confidence. Example: P04637 (TP53) returns 101 PTM features including phosphorylation sites critical for p53 regulation.