INIFTA   05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Chemical and Photochemical Reactivity of 6-Hydroxymethyl-7,8-dihydropterin in Aqueous Solutions
Autor/es:
ANDRÉS H. THOMAS; ESTHER OLIVEROS; ANDRÉ M. BRAUN; MARIELA S. ESPINOSA; CAROLINA LORENTE; M. LAURA DÁNTOLA
Revista:
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
Editorial:
JOHN WILEY & SONS LTD
Referencias:
Lugar: LOndres; Año: 2012
ISSN:
0894-3230
Resumen:
6-Hydroxymethyl-7,8-dihydropterin (H2Hmp) is
an intermediate in the biosynthesis of folate, a precursor of coenzymes
involved in the metabolism of nucleotides and amino acids. In this work, we have
investigated the reactions undergone by H2Hmp in aqueous solutions
at physiological pH, in the absence and in the presence of UV-A radiation (320
- 400 nm). In air-equilibrated solutions, H2Hmp undergoes slow
thermal oxidation (half-life 37 h) to yield 7,8-dihydroxanthopterin (H2Xap)
as the main product. The reaction of H2Hmp with hydrogen peroxide also
yields H2Xap as main product. In contrast, UV-A excitation of H2Hmp
leads to the formation of a dimer, identified by electrospray ionization mass
spectrometry. The corresponding quantum yield of H2Hmp consumption (F-R)
was independent of O2 and reactant concentration, and has a value of
0.10 (± 0.02), more than twice higher than that measured for other 6-subtituted
7,8-dihydropterins.