Photosensitized oxidation of 2?-deoxyguanosine 5?-monophosphate: Mechanism of the competitive reactions and product characterization

Artículo

Autoría:

SERRANO, MARIANA PAULA ; Estébanez, Sandra ; VIGNONI, MARIANA ; LORENTE, CAROLINA ; Vicendo, Patricia ; Oliveros, Esther ; THOMAS, ANDRES HECTOR

Fecha:

2017

Editorial y Lugar de Edición:

Royal Society of Chemistry

Revista:

NEW JOURNAL OF CHEMISTRY, vol. 41 (pp. 7273-7282) Royal Society of Chemistry

Resumen

UV-A radiation (320-400 nm) induces modifications to different biomolecules through photosensitized reactions. Oxidized pterins are efficient photosensitizers that accumulate in the skin affected by vitiligo, and photoinduce the oxidation of guanine in a process initiated by an electron transfer from the nucleobase to the triplet excited state of the photosensitizer. In this work, we have investigated the degradation of 2?-deoxyguanosine 5?-monophosphate (dGMP) photosensitized by pterin (Ptr), the parent compound of oxidized pterins, in aqueous solutions under UV-A irradiation. We have identified five products containing the oxidized guanine moiety: the deoxyribonucleoside 5?-monophosphate derivatives of imidazolone, dehydroguanidinohydantoin, guanidinohydantoin, oxazolone and spiroiminodihydantoin. An additional product with a much higher molecular weight, denoted P680, was also detected. The MS/MS analyses show that this compound contains an intact guanine moiety and a modified one. The dependence of the rate of product formation in different experimental conditions was analyzed and a general mechanistic scheme is proposed.

Palabras Clave

photosensitizationpterinsoxidized guaninephotoproducts

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http://hdl.handle.net/11336/63924