Photodimerization of 7,8-Dihydroneopterin in Aqueous Solution Under UV-A Irradiation

MARIANA VIGNONI; MARIANA P. SERRANO; ESTHER OLIVEROS; ANDRÉS H, THOMAS

PHOTOCHEMISTRY AND PHOTOBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 87 p. 51 - 55

0031-8655

7,8-Dihydroneopterin (H2Nep) is secreted during the oxidative burst of stimulated macrophages. The photochemistry of H2Nep was investigated in neutral aqueous solutions exposed to UV-A radiation (320?400 nm) at room temperature. The kinetics were followed by UV⁄ Vis spectrophotometry and HPLC, whereas the photoproducts were analyzed by electrospray ionization mass spectrometry. Excitation of H2Nep leads to the formation of isomeric dimers with molecular masses equal to exactly twice the molecular mass of the reactant. The corresponding quantum yield of H2Nep consumption (F)R = (3.8 ± 0.5) ・ 10)2) was independent of O2 and reactant concentrations. Mechanistic implications are discussed.2Nep) is secreted during the oxidative burst of stimulated macrophages. The photochemistry of H2Nep was investigated in neutral aqueous solutions exposed to UV-A radiation (320?400 nm) at room temperature. The kinetics were followed by UV⁄ Vis spectrophotometry and HPLC, whereas the photoproducts were analyzed by electrospray ionization mass spectrometry. Excitation of H2Nep leads to the formation of isomeric dimers with molecular masses equal to exactly twice the molecular mass of the reactant. The corresponding quantum yield of H2Nep consumption (F)R = (3.8 ± 0.5) ・ 10)2) was independent of O2 and reactant concentrations. Mechanistic implications are discussed.