Photochemical properties of Biopterin, Neopterina and their dihydroderivatives under UVA irradiation

MARIANA VIGNONI; FRANCO M. CABRERIZO; ANDRES H. THOMAS

Bordeaux

Simposio; XXVth IUPAC Symposium on Photochemistry; 2014

Pterins are heterocyclic compounds derived from 2-aminopteridin-4-(3H)-one or pterin. They can be found in biological systems in multiple forms and playing different roles, such as pigments or enzymatic cofactors for numerous redox and one-carbon transfer reactions. Pterins exist in different oxidation states and can be divided into
two classes: (a) oxidized or aromatic pterins and (b) reduced pterins. They behave as weak acids in aqueous solution, involving the lactam group with a pKa around 8 and 10 for oxidized and dihydroderivatives, respectively. Dihydroneopterin (H2Nep) is secreted during the oxidative burst of stimulated macrophages, dihydrobiopterin (H2Bip) and tetrahydrobiopterin are involved in the metabolism of aminoacids.In addition, HBip, biopterin (Bip) and other pterin derivatives accumulate in the skin of patients affected by vitiligo, a depigmentation disorder, where the protection against UV radiation fails due to the lack of melanin.Since pterins are involved in many photobiological processes, the interest in their photochemistry and photophysics has been increasing steadily during the past decade.