Singlet-oxygen-mediated amino acid and protein oxidation: formation of tryptophan peroxides and decomposition products
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Singlet-oxygen-mediated amino acid and protein oxidation : formation of tryptophan peroxides and decomposition products. / Gracanin, Michelle; Hawkins, Clare Louise; Pattison, David I; Davies, Michael Jonathan.
I: Free Radical Biology & Medicine, Bind 47, Nr. 1, 01.07.2009, s. 92-102.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Singlet-oxygen-mediated amino acid and protein oxidation
T2 - formation of tryptophan peroxides and decomposition products
AU - Gracanin, Michelle
AU - Hawkins, Clare Louise
AU - Pattison, David I
AU - Davies, Michael Jonathan
PY - 2009/7/1
Y1 - 2009/7/1
N2 - Proteins are major biological targets for oxidative damage within cells owing to their high abundance and rapid rates of reaction with radicals and excited-state species, including singlet oxygen. Reaction of Tyr, Trp, and His residues, both free and on proteins, with singlet oxygen generates peroxides in high yield. Peroxides have also been detected on proteins within intact cells on exposure to visible light in the presence of a photosensitizer. The structures of some of these materials have been elucidated for free amino acids, but less is known about peptide- and protein-bound species. In this study we have characterized Trp-derived peroxides, radicals, and breakdown products generated on free Trp and Trp residues in peptides and proteins, using LC/MS/MS. With free Trp, seven major photoproducts were characterized, including two isomeric hydroperoxides, two alcohols, two diols, and N-formylkynurenine, consistent with singlet oxygen-mediated reactions. The hydroperoxides decompose rapidly at elevated temperatures and in the presence of reductants to the corresponding alcohols. Some of these materials were detected on proteins after complete enzymatic (Pronase) hydrolysis and LC/MS/MS quantification, providing direct evidence for peroxide formation on proteins. This approach may allow the quantification of protein modification in intact cells arising from singlet oxygen formation.
AB - Proteins are major biological targets for oxidative damage within cells owing to their high abundance and rapid rates of reaction with radicals and excited-state species, including singlet oxygen. Reaction of Tyr, Trp, and His residues, both free and on proteins, with singlet oxygen generates peroxides in high yield. Peroxides have also been detected on proteins within intact cells on exposure to visible light in the presence of a photosensitizer. The structures of some of these materials have been elucidated for free amino acids, but less is known about peptide- and protein-bound species. In this study we have characterized Trp-derived peroxides, radicals, and breakdown products generated on free Trp and Trp residues in peptides and proteins, using LC/MS/MS. With free Trp, seven major photoproducts were characterized, including two isomeric hydroperoxides, two alcohols, two diols, and N-formylkynurenine, consistent with singlet oxygen-mediated reactions. The hydroperoxides decompose rapidly at elevated temperatures and in the presence of reductants to the corresponding alcohols. Some of these materials were detected on proteins after complete enzymatic (Pronase) hydrolysis and LC/MS/MS quantification, providing direct evidence for peroxide formation on proteins. This approach may allow the quantification of protein modification in intact cells arising from singlet oxygen formation.
KW - Alcohols
KW - Animals
KW - Cattle
KW - Chickens
KW - Electron Spin Resonance Spectroscopy
KW - Free Radicals
KW - Hydrogen Peroxide
KW - Hydrolysis
KW - Kynurenine
KW - Mass Spectrometry
KW - Muramidase
KW - Oxidation-Reduction
KW - Oxidative Stress
KW - Protein Binding
KW - Protein Processing, Post-Translational
KW - Serum Albumin, Bovine
KW - Singlet Oxygen
KW - Soybean Proteins
KW - Soybeans
KW - Tryptophan
U2 - 10.1016/j.freeradbiomed.2009.04.015
DO - 10.1016/j.freeradbiomed.2009.04.015
M3 - Journal article
C2 - 19375501
VL - 47
SP - 92
EP - 102
JO - Free Radical Biology & Medicine
JF - Free Radical Biology & Medicine
SN - 0891-5849
IS - 1
ER -
ID: 129670433