PeptidePedia The community reference

Deamidation (revision 1)

Old revision·13:39, 23 Oct 2024·AAA_Analyst

This is an old revision of this page, as it stood at 13:39, 23 Oct 2024, saved by AAA_Analyst with the summary create article — method stub. It may differ substantially from the current revision, and any error it contains may since have been corrected.
Deamidation
Residues affectedAsparagine, and more slowly glutamine
Mass change+0.984 Da
Charge changeIntroduces a negative charge
Fastest sequence contextAsn-Gly
Topic infobox · conventions

Deamidation is the conversion of an asparagine or glutamine side-chain amide to a carboxylic acid, with loss of ammonia. It is among the most common chemical degradation routes in peptides and proteins, and it proceeds spontaneously in aqueous solution without any external agent.[1]

The mass change is +0.984 Da, which is small enough that unit-resolution mass spectrometry cannot distinguish a deamidated peptide from its parent. The charge change is more consequential: an uncharged amide becomes a negatively charged carboxylate, which alters chromatographic behaviour and, in a receptor-binding peptide, may alter activity.[2]

References

  1. ^ Robinson NE, Robinson AB. "Molecular clocks." Proceedings of the National Academy of Sciences 98(3):944–949 (2001). DOI:10.1073/pnas.98.3.944. PMID 11158575.
  2. ^ United States Pharmacopeia, General Chapter <1503>, Quality Attributes of Synthetic Peptide Drug Substances.