Yates Sally A, Dempster Nicola M, Murphy Mark F, Moore Sharon A
School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK.
Rapid Commun Mass Spectrom. 2017 May 15;31(9):762-770. doi: 10.1002/rcm.7843.
The lipid peroxidation product malondialdehyde forms M dG adducts with guanine bases in genomic DNA. The analysis of these adducts is important as a biomarker of lipid peroxidation, oxidative stress and inflammation which may be linked to disease risk or exposure to a range of chemicals.
Genomic DNA samples were subjected to acid hydrolysis to release the adducts in the base form (M G) alongside the other purines. A liquid chromatography/mass spectrometry method was optimised for the quantitation of the M G adducts in genomic DNA samples using product ion and multiple reaction monitoring (MRM) scans.
Product ion scans revealed four product ions from the precursor ion; m/z 188 → 160, 133, 106 and 79. The two smallest ions have not been observed previously and optimisation of the method revealed that these gave better sensitivity (LOQ m/z 79: 162 adducts per 10 nucleotides; m/z 106: 147 adducts per 10 nucleotides) than the other two ions. An MRM method gave similar sensitivity but the two smallest product ions gave better accuracy (94-95%). Genomic DNA treated with malondialdehyde showed a linear dose-response relationship.
A fast reliable sample preparation method was used to release adducts in the base form rather than the nucleoside. The methods were optimised to selectively analyse the adducts in the presence of other DNA bases without the need for further sample clean-up. Analysis of genomic DNA gave results consistent with previous work and was applied to new samples. Thus, the method is suitable for the analysis of M (d)G adducts in biological samples. Copyright © 2017 John Wiley & Sons, Ltd.
