CONICET | Buscador de Institutos y Recursos Humanos

The biological and medical importance ofphotosensitized reactions is mainly related to their participation in processesinvolved in the development of skin cancer and in photodynamic treatmentsagainst cancer and infections. Pterins, afamily of heterocyclic compounds derived from 2-aminopteridin-4(1H)-one, are widespread in living systemsand participate in important biological functions. In pathological conditions, such as vitiligo,oxidized pterins accumulate in the white skin patches of patients sufferingthis depigmentation disorder. These moleculesare photochemically active and, under UV-A excitation (320?400 nm), they canfluoresce, produce organic radicals and reactive oxygen species and undergophotooxidation. Our research group has investigated for more than 20 years, thedegradation of biomolecules such as DNA, proteins, lipids, and theircomponents, photosensitized by pterins under UV-A irradiation. The experimentalresults include kinetics analysis, evaluation of interaction between pterins excitedstates with different substrates, detection of radical species, andidentification of products, under different experimental conditions. Dependingon the target molecule, pterin-photosensitized oxidations may be purely type I(electron transfer) or type II (singlet oxygen, 1O2), ora combination of both. In this article, we present a summary of the chemicalchanges photoinduced by pterins upon UV-A irradiation in different biomoleculesand the mechanisms involved.