amidefragment

Amidefragment is a term used in chemistry and mass spectrometry to describe a fragment that contains an amide functional group, typically arising after cleavage of a larger amide-bearing molecule. An amide fragment is the portion of the original molecule that retains the amide moiety, such as the carbonyl carbon with the attached nitrogen, and may be produced during fragmentation processes or chemical reactions that break bonds adjacent to the amide.

In mass spectrometry, amide fragments are common outcomes of tandem fragmentation of amide-containing compounds. When bonds near the amide group are cleaved, the resulting fragment ions can retain the amide linkage. In proteomics, peptide backbones routinely fragment to yield ions that preserve the amide bond; these ions are analyzed to infer sequence and modification patterns. The presence and stability of amide-containing fragments influence fragmentation pathways, charge distribution, and the observed mass spectra.

Applications and interpretation rely on recognizing amide fragments as part of larger diagnostic patterns. Identifying amide fragments can aid in determining the location of the amide bond, identifying post-translational modifications, and supporting structural or sequence assignments for peptides, proteins, and other amide-containing molecules. Outside mass spectrometry, the term may also describe fragments produced by hydrolysis or other cleavage processes that retain the amide group.

Overall, amidefragments serve as a useful concept for understanding how amide-containing molecules break apart and how the amide moiety influences fragment properties and analytical interpretation.