Production and quenching of reactive oxygen species

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, on the oxidation state of the pyrazine ring and on the pH. Formation of the superoxide anion by electron transfer between the pterin radical anion and molecular oxygen leads to the production of significant amounts of hydrogen peroxide (H2O2) by disproportionation. Dihydropterins (H2Pt) do not produce 1O2 but are oxidized by this species with high rate constants yielding pterins as well as H2O2. In contrast to aromatic derivatives, H2Pt are oxidized by H2O2, and rates and products strongly depend on the nature of the substituents on the H2Pt moiety.

Related publications

"Production and quenching of reactive oxygen species by pterin derivatives, an intriguing class of biomolecules".
E. Oliveros, M. L. Dántola, M. Vignoni, A. H. Thomas, C. Lorente, Pure Appl. Chem., 83, 801-811 (2011).

"Electron transfer processes induced by the triplet state of pterins in aqueous solutions".
M. L. Dántola, M. Vignoni, C. González, C. Lorente, P. Vicendo, E. Oliveros, A. H. Thomas, Free Rad. Biol. Med., 49, 1014–1022 (2010).

"Predictive modeling of the total deactivation rate constant of singlet oxygen by heterocyclic compounds"
A. G Mercader, P. R. Duchowicz, F. M. Fernández, E. A. Castro, F. M. Cabrerizo, A. H. Thomas, J. Mol. Graph. Mod., 28, 12-19 (2009).

"Reaction between 7,8-dihydropterins and hydrogen peroxide under physiological conditions"
M. L. Dántola, T. M. Schuler, M. P. Denofrio, M. Vignoni, A. L. Capparelli, C. Lorente, A. H. Thomas, Tetrahedron, 64, 8692-8699 (2008).

"Stability of 7,8-dihydropterins in air-equilibrated aqueous solutions"
M. L. Dántola, M. Vignoni, A. L. Capparelli, C. Lorente, A. H. Thomas, Helv. Chim. Acta, 91, 379-580 (2008).

"Singlet Oxygen (O2(1Δg)) quenching by dihydropterins"
M. L. Dántola, A. H. Thomas, A. M. Braun, E. Oliveros, C. Lorente, J. Phys. Chem. A, 111, 4280-4288 (2007).

"Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1Δg)): Physical Quenching and Chemical Reaction"
F. M. Cabrerizo, M. L. Dántola, G. Petroselli, A. L. Capparelli, A. H. Thomas, A. M. Braun, C. Lorente, E. Oliveros,
Photochem. Photobiol., 83, 526-534 (2007).

"Photoinduced generation of H2O2 and O2•‾ by 6-formylpterin in aqueous solutions"
G. Petroselli, J. M. Bartsch, A. H. Thomas, Pteridines, 17, 82-89 (2006).

"Singlet oxygen (1g) production by pterin derivatives in aqueous solutions"
A. H. Thomas, C. Lorente, A. L. Capparelli, C. G. Martínez, A. M. Braun, E. Oliveros, Photochem. Photobiol. Sci., 2, 245-250 (2003).

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