Human AP endonuclease 1 stimulates multiple-turnover base excision by alkyladenine DNA glycosylase.

ABSTRACT: Human alkyladenine DNA glycosylase (AAG) locates and excises a wide variety of damaged purine bases from DNA, including hypoxanthine that is formed by the oxidative deamination of adenine. We used steady state, pre-steady state, and single-turnover kinetic assays to show that the multiple-turnover excision of hypoxanthine in vitro is limited by release of the abasic DNA product. This suggests the possibility that the product release step is regulated in vivo by interactions with other base excision repair (BER) proteins. Such coordination of BER activities would protect the abasic DNA repair intermediate and ensure its correct processing. AP endonuclease 1 (APE1) is the predominant enzyme for processing abasic DNA sites in human cells. Therefore, we have investigated the functional effects

SUBMITTER: Baldwin MR 

PROVIDER: S-EPMC2762795 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature