INIFTA   05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1ƒ´g)): Physical Quenching and Chemical Reaction
Autor/es:
CABRERIZO FRANCO M.; DÁNTOLA M. LAURA; PETROSELLI GABRIELA; CAPPARELLI ALBERTO L.; THOMAS ANDRÉS H.; BRAUN ANDRÉ M.; LORENTE CAROLINA; OLIVEROS ESTHER
Revista:
PHOTOCHEMISTRY AND PHOTOBIOLOGY
Editorial:
Blackwell Publishing
Referencias:
Año: 2007 vol. 83 p. 526 - 534
ISSN:
0031-8655
Resumen:
Pterins (PTs) belong to a class of heterocyclic compounds present in a wide range of living systems. They participate in relevant biological functions and are involved in different photobiological processes. We have investigated the reactivity of conjugated PTs (folic acid [FA], 10-methylfolic acid [MFA], pteroic acid [PA]) and unconjugated PTs (PT, 6-hydroxymethylpterin [HPT], 6-methylpterin [MPT], 6,7-dimethylpterin [DPT], rhamnopterin [RPT]) with singlet oxygen (1O2) in aqueous solutions, and compared the efficiencies of chemical reaction and physical quenching. The chemical reactions between 1O2, produced by photosensitization, and PT derivatives were followed by UV-visible  pectrophotometry and high-performance liquid chromatography, and corresponding rate constants (kr) were evaluated. Whenever possible, products were identified and quantified. Rate constants of 1O2 total quenching by the PT derivatives investigated were obtained from steady-state 1O2 luminescence measurements. Results show that the behavior of conjugated PTs differs considerably from that of unconjugated derivatives, and the mechanisms of 1O2 physical quenching by these compounds and of their chemical reaction with 1O2 are discussed in relation to their structural features.