MASS SPECTRA OF URIDINE AND PSEUDOURIDINE - FRAGMENTATION PATTERNS CHARACTERISTIC OF A CARBON-CARBON NUCLEOSIDIC BOND

The mass spectrum of uridine contains intense peaks at m/e 112, 113 and 133, generated by uracil, protonated uracil, and the ribose moiety respectively. This pattern is characteristic of all nucleosides containing a carbon-nitrogen nucleosidic bond. In contrast, the spectrum of pseudouridine lacks these peaks, but has an intense peak at m/e 141 due to protonated 5-formyluracil. The carbon-carbon nucleosidic bond is not cleaved in the mass spectrometer; neither the sugar nor the base moiety undergoes fragmentation independently. This feature is predicted to be general for nucleosides containing a carbon-carbon nucleosidic bond. © 1969.