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

TY - JOUR

T1 - Quantification of hydroxyl radical-derived oxidation products in peptides containing glycine, alanine, valine, and proline

AU - Morgan, Philip E

AU - Pattison, David I

AU - Davies, Michael Jonathan

N1 - Copyright © 2011 Elsevier Inc. All rights reserved.

PY - 2012/1/15

Y1 - 2012/1/15

N2 - 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.

AB - 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.

KW - Alanine

KW - Alcohols

KW - Amino Acid Sequence

KW - Gamma Rays

KW - Glycine

KW - Hydrogen Peroxide

KW - Hydroxyl Radical

KW - Molecular Weight

KW - Oxidation-Reduction

KW - Oxygen

KW - Peptides

KW - Proline

KW - Protein Carbonylation

KW - Proteolysis

KW - Tandem Mass Spectrometry

KW - Valine

U2 - 10.1016/j.freeradbiomed.2011.10.448

DO - 10.1016/j.freeradbiomed.2011.10.448

M3 - Journal article

C2 - 22064365

SN - 0891-5849

VL - 52

SP - 328

EP - 339

JO - Free Radical Biology & Medicine

JF - Free Radical Biology & Medicine

IS - 2

ER -