Identification and Quantification of 8,5'-Cyclo-2'-Deoxyadenosine in DNA by Liquid Chromatography/Mass Spectrometry

Published

April 1, 2001

Author(s)

M. Dizdaroglu, Pawel Jaruga, H Rodriguez

Abstract

Recent studies suggested that 8,5'-cyclo-2'-deoxyadenosine may play a role in diseases with defective nucleotide-excision repair. This compound is one of the major lesions formed in DNA by hydroxyl radical attack on sugar moiety of 2'-deoxyadenosine. It is likely to be repaired by nucleotide-excision repair rather than by base-excision repair because of a covalent bond between the sugar and base moieties. We studied the measurement of 8,5'-cyclo-2'-deoxyadenosine in DNA by liquid chromatography/isotope-dilution mass spectrometry. A methodology was developed for the analysis of 8,5' cyclo-2'-deoxyadenosine by liquid chromatography in DNA hydrolyzed to nucleosides by a combination of four enzymes, i.e., DNase I, phosphodiesterases I and II, and alkaline phosphatase. Detection by mass spectrometry was performed using atmospheric pressure ionization-electrospray process in the positive ionization mode. Results showed that liquid chromatography/isotope-dilution mass spectrometry is well suited for identification and quantification of 8,5'- cyclo-2'-deoxyadenosine in DNA. Both (5'R)- and (5'S)-diastereomers of 8.5'-cyclo-2'deosyadenosine were detected. The level of sensitivity of liquid chromatography/massspectrometry with selected-ion monitoring amounted to circa 5 fmol of this compound on the column. The yield of 8,5' -cyclo- 2'-deoxyadenosine was measured in DNA in aqueous solution exposed to ionizing radiation at doses from 2.5 to 80 Gray. Gas chromatography/mass spectrometry was also used to measure this compound in DNA. Both techniques yielded similar results. The yield of 8,5'-cyclo-2'-deoxyadenosine was comparable to the yields of some of the other major modified bases in DNA, which were measured using gas chromatography/mass spectrometry. The measurement of 8,5'-cyclo-2'-deoxyadenosine by liquid chromatography/mass spectrometry may contribute to the understanding of its biological properties and its role in diseases with defective nucleotide-excision repair.

Citation

Free Radical Biology and Medicine

Volume

30

Issue

7

Pub Type

Journals

Keywords

8, 5'-cyclo-purine nucleosides, free radicals, mass spectrometry, nucleotide-excision repair, oxidative DNA damage

Citation

Dizdaroglu, M. , Jaruga, P. and Rodriguez, H. (2001), Identification and Quantification of 8,5'-Cyclo-2'-Deoxyadenosine in DNA by Liquid Chromatography/Mass Spectrometry, Free Radical Biology and Medicine (Accessed December 15, 2024)