کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8271429 | 1534979 | 2013 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Tryptophan oxidation photosensitized by pterin
ترجمه فارسی عنوان
اکسیداسیون تریپتوفان با حساسیت فتوسنتز شده توسط پترین
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
سالمندی
چکیده انگلیسی
Pterins are normal components of cells and they have been previously identified as good photosensitizers under UV-A irradiation, inducing DNA damage and oxidation of nucleotides. In this work, we have investigated the ability of pterin (Ptr), the parent compound of oxidized pterins, to photosensitize the oxidation of another class of biomolecules, amino acids, using tryptophan (Trp) as a model compound. Irradiation of Ptr in the UV-A spectral range (350Â nm) in aerated aqueous solutions containing Trp led to the consumption of the latter, whereas the Ptr concentration remained unchanged. Concomitantly, hydrogen peroxide (H2O2) was produced. Although Ptr is a singlet oxygen (1O2) sensitizer, the degradation of Trp was inhibited in O2-saturated solutions, indicating that a 1O2-mediated process (type II oxidation) was not an important pathway leading to Trp oxidation. By combining different analytical techniques, we could establish that a type I photooxidation was the prevailing mechanism, initiated by an electron transfer from the Trp molecule to the Ptr triplet excited state, yielding the corresponding radical ions (Trp+/Trp(-H) and Ptrâ). The Trp reaction products that could be identified by UPLC-mass spectrometry are in agreement with this conclusion.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 63, October 2013, Pages 467-475
Journal: Free Radical Biology and Medicine - Volume 63, October 2013, Pages 467-475
نویسندگان
Andrés H. Thomas, Mariana P. Serrano, Virginie Rahal, Patricia Vicendo, Catherine Claparols, Esther Oliveros, Carolina Lorente,