Photosensitization of 2'-deoxyadenosine-5'-monophosphate by pterin.
UV-A radiation (320-400 nm) induces damages to the DNA molecule and its components through photosensitized reactions. 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'-deoxyadenosine-5'-monophosphate (dAMP) by pterin (PT) in aqueous solution under UV-A radiation. The effect of pH was evaluated, the participation of oxygen was investigated and the products analyzed. Kinetic studies revealed that the reactivity of dAMP towards singlet oxygen (1O2) is very low and that this reactive oxygen species does not participate in the mechanism of photosensitization, although it is produced by PT upon UV-A excitation. In contrast, analysis of irradiated solutions by means of electrospray ionization mass spectrometry strongly suggested that 8-oxo-7,8-dihydro-2'-deoxyadenosine-5'-monophosphate (8-oxo-dAMP) was produced, indicating that the photosensitized oxidation takes place via a type I mechanism (electron transfer).
Petroselli
Gabriela
G
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET, Casilla de Correo 16, Sucursal 4, (1900) La Plata, Argentina.
Erra-Balsells
Rosa
R
Cabrerizo
Franco M
FM
Lorente
Carolina
C
Capparelli
Alberto L
AL
Braun
André M
AM
Oliveros
Esther
E
Thomas
Andrés H
AH
D003838:Deoxyadenine Nucleotides / Q000737:chemistry*; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D017319:Photosensitizing Agents / Q000737:chemistry*; D011622:Pterins / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
D003838:Deoxyadenine Nucleotides; D017319:Photosensitizing Agents; D011622:Pterins; D026082:Singlet Oxygen; C012873:2'-deoxy-5'-adenosine monophosphate; D010100:Oxygen