Figure 3.
Capillary HPLC-ESI+-MS/MS analysis of O6-Me-G remaining in the synthetic DNA duplex (5'-GTA GTT GGA GCT [O6-Me-G]GT GGC GTA GGC AAG AGT-3', + complement) following incubation with the AGT repair protein. Double stranded DNA oligomer (1 pmol) was incubated with 600 fmol AGT for 10 seconds, followed by acid hydrolysis, addition of O6-CD3-G internal standard, and HPLC-ESI+-MS/MS analysis as shown in Figure 1. The mass spectrometer was operated in the selected reaction monitoring mode by following the transitions m/z 169.1 → 152.0 and m/z 166.1 → 149.0 for O6-CD3-G and O6-Me-G , respectively.
