Characterization of Spiroiminodihydantoin as a Product of One-Electron Oxidation of 8-Oxo-7,8-dihydroguanosine
摘要:
[GRAPHICS]Further oxidation of the common DNA lesion 8-oxo-7,8-dihydroguanosine by one-electron oxidants such as IrCl62-, Fe(CN)(6)(3-), or SO4- leads to two major products, depending upon reaction conditions. In nucleosides at pH 7, 22 degrees C, the principal product is shown herein to be a spiroiminodihydantoin nucleoside, as a diastereomeric mixture, that can be characterized by NMR, ESI-MS/MS, and independent synthesis.
Spirodihydantoin Is a Minor Product of 5-Hydroxyisourate in Urate Oxidation
作者:Hongbin Yu、Jacquin C. Niles、John S. Wishnok、Steven R. Tannenbaum
DOI:10.1021/ol048547w
日期:2004.9.1
Spirodihydantoin is a minor product from oxidation of uric acid (similar to0.15% yield), while spiroiminodihydantoin is a major product from oxidation of 8-oxo-7,8-dihydroguanine (37% yield, pH 10.2). High pH and temperature favor the formation of both spiro compounds. O-18 labeling experiments and in situ generation and decomposition of 5-hydroxy-N7-methylisouric acid indicate that spirodihydantoin and allantoin and spiroiminodihydantoin and guanidinohydantoin are products of 5-hydroxyisourate and 5-hydroxy-8-oxo-7,8-dihydroguanine intermediates, respectively.