INIFTA   05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Production and quenching of reactive oxygen species by pterin derivatives, an intriguing class of biomolecules
Autor/es:
ESTHER OLIVEROS; M. LAURA DÁNTOLA; MARIANA VIGNONI; ANDRÉS H. THOMAS; CAROLINA LORENTE
Revista:
PURE AND APPLIED CHEMISTRY
Editorial:
INT UNION PURE APPLIED CHEMISTRY
Referencias:
Año: 2011 vol. 83 p. 801 - 811
ISSN:
0033-4545
Resumen:
Pterins, a family of heterocyclic compounds derived from 2-aminopteridin-4(1H)-one, are widespread in living systems and participate in important biological functions, suchas metabolic redox processes. Under UV-A excitation (320?400 nm), aromatic pterins (Pt)can generate reactive oxygen species (ROS), as a consequence of both energy- and electrontransfer processes from their triplet excited state. Quantum yields of singlet oxygen (1O2)production depend largely on the nature of the substituents on the pterin moiety and on thepH. Formation of the superoxide anion by electron transfer between the pterin radical anionand molecular oxygen leads to the production of significant amounts of hydrogen peroxide(H2O2) by disproportionation. Dihydropterins (H2Pt) do not produce 1O2 but are oxidized bythis species with high rate constants yielding pterins as well as H2O2. In contrast to aromaticderivatives, H2Pt are oxidized by H2O2, and rates and products strongly depend on the natureof the substituents on the H2Pt moiety. Aromatic pterins have been found in vivo underpathological conditions, e.g., biopterin or 6-carboxypterin are present in the skin of patientsaffected by vitiligo, a depigmentation disorder. The biomedical implications of the productionof ROS by pterin derivatives and their reactivity with these species are discussed.