INVESTIGADORES
THOMAS Andres Hector
congresos y reuniones científicas
Título:
Solar Radiation Exposure of Dihydrobiopterin and Biopterin in Aqueous Solution
Autor/es:
ADRIANA IPIÑA; CAROLINA CASTAÑO; CAROLINA LORENTE; ANDRÉS H. THOMAS
Lugar:
Córdoba
Reunión:
Congreso; 16th International Congress on Photobiology; 2014
Institución organizadora:
International Union of Photobiology
Resumen:
Dihydrobiopterin (H2Bip) and Biopterin (Bip) accumulate in the
skin of patients suffering from vitiligo. H2Bip and Bip undergo
photooxidation upon UV radiation and the latter acts as a photosensitizer of
biomolecules [1-2]. In this work we analyse the photochemical reactions of these
compounds exposed to sunlight in La Plata (34.90ºS, 57.92ºW) between Spring
equinox and Summer solstice period, recording the spectral solar irradiance
with a high-resolution spectrometer. The photochemical reactions were followed
by HPLC and UV-Vis spectrophotometry. Under solar exposure H2Bip
undergoes dimerization and oxidation to Bip, which, in turn, is photooxidized
into 6-formylpterin (Fop). Additionally, UV excitation induces the oxidation of
Fop to 6-carboxypterin, which is much more photostable than Bip and Fop and
then it is accumulated in the solution. Rates of reactant consumption and
quantum yields were determined under different meteorological conditions. We
have demonstrated that solar radiation causes significant oxidation of the
pterin derivatives investigated, even in cloudy days. The biological
implications of our results are discussed.
Acknowledgments The authors
thank CONICET for the postdoctoral fellowship and IFIR-CONICET-UNR for letting
us borrow the spectrometer.
[1] [1] M. Vignoni, F.M. Cabrerizo, C. Lorente, C. Claparols, E. Oliveros,
A.H. Thomas, Org. Biomol. Chem., 2010, 8 (4),
800.
[2] M. Vignoni, F.M. Cabrerizo, C. Lorente, A.H. Thomas, Photochem. Photobiol., 2009, 85(1), 365.