Quantification of hydroxyl radical-derived oxidation products in peptides containing glycine, alanine, valine, and proline

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Philip E Morgan, David I Pattison, Michael Jonathan Davies

Proteins are a major target for oxidation due to their abundance and high reactivity. Despite extensive investigation over many years, only limited quantitative data exist on the contributions of different pathways to the oxidation of peptides and proteins. This study was designed to obtain quantitative data on the nature and yields of oxidation products (alcohols, carbonyls, hydroperoxides, fragment species) formed by a prototypic oxidant system (HO(•)/O(2)) on small peptides of limited, but known, amino acid composition. Peptides composed of Gly, Ala, Val, and Pro were examined with particular emphasis on the peptide Val-Gly-Val-Ala-Pro-Gly, a repeat motif in elastin with chemotactic activity and metalloproteinase regulation properties. The data obtained indicate that hydroperoxide formation occurs nonrandomly (Pro > Val > Ala > Gly) with this inversely related to carbonyl yields (both peptide-bound and released). Multiple alcohols are generated at both side-chain and backbone sites. Backbone fragmentation has been characterized at multiple positions, with sites adjacent to Pro residues being of major importance. Summation of the product concentrations provides clear evidence for the occurrence of chain reactions in peptides exposed to HO(•)/O(2), with the overall product yields exceeding that of the initial HO(•) generated.

Original languageEnglish
JournalFree Radical Biology & Medicine
Volume52
Issue number2
Pages (from-to)328-39
Number of pages12
ISSN0891-5849
DOIs
Publication statusPublished - 15 Jan 2012
Externally publishedYes

    Research areas

  • Alanine, Alcohols, Amino Acid Sequence, Gamma Rays, Glycine, Hydrogen Peroxide, Hydroxyl Radical, Molecular Weight, Oxidation-Reduction, Oxygen, Peptides, Proline, Protein Carbonylation, Proteolysis, Tandem Mass Spectrometry, Valine

ID: 128975229