Detection of 2-Deoxy-D-ribose Radicals Generated by the Reaction with the Hydroxyl Radical using a Rapid Flow-ESR Method

Abstract

ESR spectrum of the short-lived radicals derived from 2-deoxy-D-ribose by the reaction with the hydroxyl radical (HO^·) was measured using a rapid flow method. A dielectric mixing resonator was used for the measurement, which made it possible to measure the highly sensitive ESR spectra of the radicals with a lifetime of the order of milliseconds. A complex spectrum was obtained and the spectral simulation was done to show that it was the superposition of the signals due to five radicals (I-V). Three of them were those formed by the dehydrogenation with the HO^· at C-1 (I), C-3 (II), and C-4 (III) positions of the 2-deoxy-D-ribose molecule. The other two (IV and V) were carbonyl-conjugated radicals formed by the elimination of a water molecule from III and II. The results showed that dehydrogenation occurred randomly at the positions where hydroxyl groups are attached, but the most preferred position was C-3 and the radical position moved from C-3 to C-4 by the elimination of water molecule.

• deoxyribose radical
• flow ESR method
• hydroxyl radical
• mixing resonator