INIFTA   05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Oxidation of 2´-Deoxyguanosine 5´-Monophosphate Photoinduced by Pterin: Type I versus Type II Mechanism
Autor/es:
GABRIELA PETROSELLI; M. LAURA DÁNTOLA; FRANCO M. CABRERIZO; ALBERTO L. CAPPARELLI; CAROLINA LORENTE; ESTHER OLIVEROS; ANDRE´S H. THOMAS
Revista:
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Editorial:
ACS
Referencias:
Lugar: Washington; Año: 2008 vol. 130 p. 3001 - 3011
ISSN:
0002-7863
Resumen:
UV-A radiation (320-400 nm) induces damages to the DNA molecule and its components through different photosensitized reactions. The main processes responsible for those damages are photosensitized oxidations that involve an electron abstraction (type I) and/or the production of singlet molecular oxygen (1O2) (type II). Pterins, heterocyclic compounds widespread in biological systems, participate in relevant biological processes and are able to act as photosensitizers. We have investigated the photosensitization of 2'-deoxyguanosine-5'-monophosphate (dGMP) by pterin (PT) in aqueous solution under UV-A radiation. Kinetic analysis was employed to evaluate the participation of both types of mechanism under different pH conditions. The rate constant of 1O2 total quenching (kt) by dGMP was determined by steady-state analysis of the 1O2 luminescence, whereas the rate constant of the chemical reaction between 1O2 and dGMP (kr) was evaluated from kinetic analysis of concentration profiles obtained by HPLC. The biological implications of the results obtained are also discussed.