Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9876369 | Radiation Physics and Chemistry | 2005 | 6 Pages |
Abstract
The reaction of oxide radical ions (Oâ) with nucleosides 1-5 at pH 13.7 has been investigated by the pulse radiolysis technique. Rate constants for the reaction of the Oâ radical with the various nucleosides are in the range of (0.7-1.3)Ã109 Mâ1 sâ1. The intermediate derived from uridine (1) disappeared by second-order kinetics, whereas the initial transient species derived from 2â²-deoxyribonucleosides (2-5) undergo unimolecular transformations with rate constant in the range of (0.6-1.0)Ã104 sâ1 followed by a second slower unimolecular process with rate constant in the range of 30-50 sâ1. The observed differences suggest two distinct mechanistic paths. In the uridine case, hydrogen abstraction preferentially occurs at the C2â² position, whereas in the 2â²-deoxynucleosides favored hydrogen abstraction occurs at the C5â² position. Both attacks lead to release of the base as shown by γ-radiolysis experiments associated with product studies.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Radiation
Authors
Chryssostomos Chatgilialoglu, Marcella Ioele, Quinto G. Mulazzani,