Mechanism of electron transfer processes photoinduced by lumazine

UV-A (320–400 nm) and UV-B (280–320 nm) radiation causes damage to DNA and other biomolecules through reactions induced by different endogenous or exogenous photosensitizers. Lumazines are heterocyclic compounds present in biological systems as biosynthetic precursors and/or products of metabolic de...

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Autores principales: Denofrio, María Paula, Dántola, María Laura, Vicendo, Patricia, Oliveros, Esther, Thomas, Andrés Héctor, Lorente, Carolina
Formato: Articulo
Lenguaje:Inglés
Publicado: 2012
Materias:
Ciencias Exactas
electron transfer
lumazine
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/130519
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-130519
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
electron transfer
lumazine
spellingShingle Ciencias Exactas
electron transfer
lumazine
Denofrio, María Paula
Dántola, María Laura
Vicendo, Patricia
Oliveros, Esther
Thomas, Andrés Héctor
Lorente, Carolina
Mechanism of electron transfer processes photoinduced by lumazine
topic_facet Ciencias Exactas
electron transfer
lumazine
description UV-A (320–400 nm) and UV-B (280–320 nm) radiation causes damage to DNA and other biomolecules through reactions induced by different endogenous or exogenous photosensitizers. Lumazines are heterocyclic compounds present in biological systems as biosynthetic precursors and/or products of metabolic degradation. The parent and unsubstituted compound called lumazine (pteridine-2,4(1,3H)-dione; Lum) is able to act as photosensitizer through electron transfer-initiated oxidations. To get further insight into the mechanisms involved, we have studied in detail the oxidation of 2′-deoxyadenosine 5′-monophosphate (dAMP) photosensitized by Lum in aqueous solution. After UV-A or UV-B excitation of Lum and formation of its triplet excited state (³Lum*), three reaction pathways compete for the deactivation of the latter: intersystem crossing to singlet ground state, energy transfer to O₂, and electron transfer between dAMP and ³Lum* yielding the corresponding pair of radical ions (Lum˙⁻ and dAMP˙⁺). In the following step, the electron transfer from Lum˙⁻ to O₂ regenerates Lum and forms the superoxide anion (O₂˙⁻), which undergoes disproportionation into H₂O₂ and O₂. Finally dAMP˙⁺ participates in subsequent reactions to yield products.
format Articulo
Articulo
author Denofrio, María Paula
Dántola, María Laura
Vicendo, Patricia
Oliveros, Esther
Thomas, Andrés Héctor
Lorente, Carolina
author_facet Denofrio, María Paula
Dántola, María Laura
Vicendo, Patricia
Oliveros, Esther
Thomas, Andrés Héctor
Lorente, Carolina
author_sort Denofrio, María Paula
title Mechanism of electron transfer processes photoinduced by lumazine
title_short Mechanism of electron transfer processes photoinduced by lumazine
title_full Mechanism of electron transfer processes photoinduced by lumazine
title_fullStr Mechanism of electron transfer processes photoinduced by lumazine
title_full_unstemmed Mechanism of electron transfer processes photoinduced by lumazine
title_sort mechanism of electron transfer processes photoinduced by lumazine
publishDate 2012
url http://sedici.unlp.edu.ar/handle/10915/130519
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