- Plant phenolics affect oxidation of tryptophan
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The effect of berry phenolics such as anthocyanins, ellagitannins, and proanthocyanidins from raspberry (Rubus idaeus), black currant (Ribes nigrum), and cranberry (Vaccinium oxycoccus) and byproducts of deoiling processes rich in phenolics such as rapese
- Salminen, Hanna,Heinonen, Marina
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experimental part
p. 7472 - 7481
(2010/04/29)
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- Reaction du L-tryptophane avec le radical peroxyle du trichlorocarbone (CCl3OO*) et l'oxygene singulet (1O2): formation des differentes paires d'hydroperoxydes isomeriques
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Radiolytic formation of the trichloromethylperoxy radical, in an oxygenated aqueous solution containing L-tryptophan, results in the formation of two new hydroperoxides which were identified as the epimeric hydroperoxyoxindolylalanines 6 and 7.These peroxides are suggested to be formed via addition of the CCl3OO* radical onto the C(2) of the indole ring followed by addition of molecular oxygen onto the resulting carbon centered radical and subsequent decomposition of the trichloromethylperoxy adduct.Thermal decomposition of the primary hydroperoxides 6 and 7gives a series of known L-tryptophan degradation products including N-formylkynurenine (10), L-kynurenine (9), and the corresponding epimeric alcohols 5 and 8.Trichloromethylperoxy addition onto the C(2) or C(3) of L-tryptophan following rearrangement to yield an intermediate 2,3-epoxide derivative, may explain the formation of oxindolylalanine (11) and the epimeric hydroxypyrroloindoles 1 and 3 via epoxide hydrolysis.The hydroperoxides 6 and 7 are distinctly different from those observed upon singlet oxygen oxidation of L-tryptophan and together with their degradation and rearrangement products, these hydroperoxides could serve as probes to study mechanisms of the oxidative degradation of proteins.
- Langlois, R.,Ali, H.,Lier, J. E. van
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p. 985 - 1000
(2007/10/02)
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