Repair Kinetics of Abasic Sites in Mammalian Cells Selectively Monitored by the Aldehyde Reactive Probe (ARP)

Abstract

Human methylpurine N-glycosylase (MPG) activity was investigated by monitoring abasic (AP) sites resulting from removal of alkylated bases. The amount of AP sites in MMS-treated HeLa cells transiently increased at 3 h, then gradually decreased to 40% at 24 h. The presence of adenine, an inhibitor of AP endonucleases, in the repair incubation of MMS-treated cells induced moderate accumulation of AP sites, suggesting inhibition of the activities of MPG as well as AP endonucleases by adenine metabolites.