title: Identification of a new type of fragment ion in the collisional activation spectra of peptides allows leucine/isoleucine differentiation.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D007532:Isoleucine / Q000032:analysis*; D007930:Leucine / Q000032:analysis*; D013058:Mass Spectrometry; D010455:Peptides / Q000032:analysis* / Q000138:chemical synthesis
chemical_list: D010455:Peptides; D007532:Isoleucine; D007930:Leucine