Synthesis of isotopically labelled DNA degradation products for use in mass spectrometric studies of cellular DNA damage

Abstract

SUMMARYThirteen substituted purines and pyrimidines bearing from three to five carbon, nitrogen and/or deuterium isotopic labels have been synthesized in yields ranging from . l to 70%. Most of the products originate from the same small number of commercially available labelled starting materials, and in several cases one intermediate leads to two products, thus minimizing the expense and time required. The parent compounds are found in tissue as the result of DNA damage often linked with carcinogenesis and mutagenesis. The synthesized compounds serve as internal standards for the study of DNA damage using mass spectrometry.

Measurements of microwave and NMR spectra for 15N substituted formamidinium formate

“…1 JC-N and 2 JN-H. As mentioned previously, 2 the values of 1 JC-H for H-CO2 of 189-196 Hz compare well with 194.8 Hz for sodium formate in D2O, 23 while a good comparison with the values of 1 JC-Hfor H-CN2 of 188-191 Hz is the 199 Hz reported for1 JC-H at C-2 of 1,3-di( 15 N)-labelled 8hydroxyadenine 19. …”

“…As shown in Figure 2 for CD3OD solution, the incorporation of 15 N results in observation of a triplet for HC 15 N2 in both 1 H and 13 C spectra with the values of 2 JH-N and 1 JC-N available directly. It is rather difficult to find good literature values for comparison, but the spectrum of 8-hydroxyadenine labelled with 15 N at positions 1 and 3 is reported to give a value of 14 Hz for the 2-bond coupling to 2-H, 19 significantly higher than our values of 3. of its hydrochloride salt. 20 As we noted previously, 2 the magnitude of 1 JC-H is known to show some correlation with the bond order and degree of hybridization.…”

“…Hz. For the magnitude of 1 JC-N there is more literature precedent and our values of 16.7-18.4 Hz can be compared with 9.7 Hz for C-2 of 1,3-di( 15 N)-labelled 8-hydroxyadenine,19 7.2 Hz for C-2 of 1,3-di( 15 N)-labelled 4,6-diamino-5formamidopyrimidine,19 17.8 Hz for C-5 of 5-formyl( 15 N)amino-labelled 4,6-diamino-5-formamidopyrimidine,19 10.7 Hz for 1 JN3-C4 of an N-acetylsydnonimine,20 and 23.7 Hz for 1 JN6-C5…”

Comparison of the levels of 8-hydroxyguanine in DNA as measured by gas chromatography mass spectrometry following hydrolysis of DNA by Escherichia coli Fpg protein or formic acid

“…These include the values measured by GC/ MS, HPLC and other techniques. The 8-OH-Gua levels measured by GC/MS varied from 21.5 to 86.7 lesions/10 6 DNA bases (or 10-40.3 lesions/10 5 guanines) (columns 7-11), whereas those measured by HPLC were in the range of 10.5 to 39.4 lesions/10 6 DNA bases (or 4.9 to 18.3 lesions/10 5 guanines) (columns [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Three values obtained by other techniques were from 12.3 to 37.2 lesions/10 6 DNA bases (or 5.7 to 17.3 lesions/10 5 guanines) (columns [26][27][28].…”

Ne-22 Ion-Beam Radiation Damage to DNA: From Initial Free Radical Formation to Resulting DNA-Base Damage

“…The experimental part is divided in sections, viz., (a) the materials used, (b) hydrated DNA sample preparation, − ,− (c) Ne-22 ion-beam and γ-irradiation (Figures S1 and S2, eqs S1 and S2), − (d) electron spin resonance (ESR) spectroscopy and computer analyses, − ,− and (e) measurements of DNA lesions. − All these are described in the Supporting Information.…”