x-ion

{
  "id": "MLC-T-CHM-012742",
  "term": "x-ion",
  "field": "Chemistry",
  "definition": "A peptide fragment ion that contains the C-terminus, formed when the peptide backbone breaks at the bond between an alpha carbon and the neighbouring carbonyl carbon. It is the C-terminal counterpart of the a-ion from the same cleavage, and its subscript gives the number of residues it contains. Its mass is 25.979 Da above that of the y-ion with the same residues.",
  "subject": "Analytical Chemistry",
  "references": [
    "PAC, 2013, 85, 1515. 'Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013)' on page 1600 (https://doi.org/10.1351/PAC-REC-06-04-06)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/x-ion/"
}