Separation, detection, and quantification of hydroperoxides formed at side-chain and backbone sites on amino acids, peptides, and proteins
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Separation, detection, and quantification of hydroperoxides formed at side-chain and backbone sites on amino acids, peptides, and proteins. / Morgan, Philip E; Pattison, David I; Hawkins, Clare Louise; Davies, Michael Jonathan.
In: Free Radical Biology & Medicine, Vol. 45, No. 9, 01.11.2008, p. 1279-89.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Separation, detection, and quantification of hydroperoxides formed at side-chain and backbone sites on amino acids, peptides, and proteins
AU - Morgan, Philip E
AU - Pattison, David I
AU - Hawkins, Clare Louise
AU - Davies, Michael Jonathan
PY - 2008/11/1
Y1 - 2008/11/1
N2 - Hydroperoxides are major reaction products of radicals and singlet oxygen with amino acids, peptides, and proteins. However, there are few data on the distribution of hydroperoxides in biological samples and their sites of formation on peptides and proteins. In this study we show that normal-or reversed-phase gradient HPLC can be employed to separate hydroperoxides present in complex systems, with detection by postcolumn oxidation of ferrous xylenol orange to the ferric species and optical detection at 560 nm. The limit of detection (10-25 pmol) is comparable to chemiluminescence detection. This method has been used to separate and detect hydroperoxides, generated by hydroxyl radicals and singlet oxygen, on amino acids, peptides, proteins, plasma, and intact and lysed cells. In conjunction with EPR spin trapping and LC/MS/MS, we have obtained data on the sites of hydroperoxide formation. A unique fingerprint of hydroperoxides formed at alpha-carbon (backbone) positions has been identified; such backbone hydroperoxides are formed in significant yields only when the amino acid is part of a peptide or protein. Only side-chain hydroperoxides are detected with free amino acids. These data indicate that free amino acids are poor models of protein damage induced by radicals or other oxidants.
AB - Hydroperoxides are major reaction products of radicals and singlet oxygen with amino acids, peptides, and proteins. However, there are few data on the distribution of hydroperoxides in biological samples and their sites of formation on peptides and proteins. In this study we show that normal-or reversed-phase gradient HPLC can be employed to separate hydroperoxides present in complex systems, with detection by postcolumn oxidation of ferrous xylenol orange to the ferric species and optical detection at 560 nm. The limit of detection (10-25 pmol) is comparable to chemiluminescence detection. This method has been used to separate and detect hydroperoxides, generated by hydroxyl radicals and singlet oxygen, on amino acids, peptides, proteins, plasma, and intact and lysed cells. In conjunction with EPR spin trapping and LC/MS/MS, we have obtained data on the sites of hydroperoxide formation. A unique fingerprint of hydroperoxides formed at alpha-carbon (backbone) positions has been identified; such backbone hydroperoxides are formed in significant yields only when the amino acid is part of a peptide or protein. Only side-chain hydroperoxides are detected with free amino acids. These data indicate that free amino acids are poor models of protein damage induced by radicals or other oxidants.
KW - Amino Acids
KW - Animals
KW - Carbon
KW - Cell Line
KW - Chromatography, High Pressure Liquid
KW - Electron Spin Resonance Spectroscopy
KW - Humans
KW - Hydrogen Peroxide
KW - Hydroxyl Radical
KW - Mass Spectrometry
KW - Mice
KW - Peptides
KW - Proteins
U2 - 10.1016/j.freeradbiomed.2008.08.004
DO - 10.1016/j.freeradbiomed.2008.08.004
M3 - Journal article
C2 - 18762246
VL - 45
SP - 1279
EP - 1289
JO - Free Radical Biology & Medicine
JF - Free Radical Biology & Medicine
SN - 0891-5849
IS - 9
ER -
ID: 129670612