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Biological hydroperoxides and singlet molecular oxygen generation
Author(s) -
Miyamoto Sayuri,
Ronsein Graziella E.,
Prado Fernanda M.,
Uemi Miriam,
Corrêa Thais C.,
Toma Izaura N.,
Bertolucci Agda,
Oliveira Mauricio C. B.,
Motta Flávia D.,
Medeiros Marisa H. G.,
Mascio Paolo Di
Publication year - 2007
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216540701242508
Subject(s) - chemistry , singlet oxygen , radical , photochemistry , peroxynitrite , mass spectrometry , oxygen , chromatography , organic chemistry , superoxide , enzyme
The decomposition of lipid hydroperoxides (LOOH) into peroxyl radicals is a potential source of singlet molecular oxygen (1O2) in biological systems. Recently, we have clearly demonstrated the generation of 1O2 in the reaction of lipid hydroperoxides with biologically important oxidants such as metal ions, peroxynitrite and hypochlorous acid. The approach used to unequivocally demonstrate the generation of 1O2 in these reactions was the use of an isotopic labeled hydroperoxide, the 18O‐labeled linoleic acid hydroperoxide, the detection of labeled compounds by HPLC coupled to tandem mass spectrometry (HPLC‐MS/MS) and the direct spectroscopic detection and characterization of 1O2 light emission. Using this approach we have observed the formation of 18O‐labeled 1O2 by chemical trapping of 1O2 with anthracene derivatives and detection of the corresponding labeled endoperoxide by HPLC‐MS/MS. The generation of 1O2 was also demonstrated by direct spectral characterization of 1O2 monomol light emission in the near‐infrared region (λ = 1270 nm). In summary, our studies demonstrated that LOOH can originate 1O2. The experimental evidences indicate that 1O2 is generated at a yield close to 10% by the Russell mechanism, where a linear tetraoxide intermediate is formed in the combination of two peroxyl radicals. In addition to LOOH, other biological hydroperoxides, including hydroperoxides formed in proteins and nucleic acids, may also participate in reactions leading to the generation 1O2. This hypothesis is currently being investigated in our laboratory.