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

MARIANA VIGNONI, MARIANA P. SERRANO, ESTHER OLIVEROS AND ANDRES 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 oxidativeburst of stimulated macrophages. The photochemistry of H2Nepwas investigated in neutral aqueous solutions exposed to UV-Aradiation (320–400 nm) at room temperature. The kinetics werefollowed by UV-Vis spectrophotometry and HPLC, whereas thephotoproducts were analyzed by electrospray ionization massspectrometry. Excitation of H2Nep leads to the formation ofisomeric dimers with molecular masses equal to exactly twice themolecular mass of the reactant. The corresponding quantumyield of H2Nep consumption (F)R = (3.8 ± 0.5) · 10)2) wasindependent of O2 and reactant concentrations. Mechanisticimplications are discussed.