title: Formation, detection and repair of AP sites.
abstract: The paper is an outline review of the main aspects concerning the formation and repair of AP (apurinic/apyrimidinic) sites in DNA as well as some of the chemical properties allowing their quantitative determination. A new method for the measurement of AP sites based on their reaction with [14C]methoxyamine is described. It has been applied to the measurement of AP sites produced in DNA either by physical (gamma-rays) or chemical (methyl methanesulphonate, osmium tetroxide) agents. The method has also been used to quantify the excision of abnormal bases from DNA under the action of specific DNA glycosylases and to prevent the chemical or enzymatic degradation of DNA containing AP sites. The paper contains data about the purification and characterization of uracil-DNA glycosylase and AP endodeoxyribonuclease from carrot cells, two enzymes involved in the first steps of base excision repair through AP site intermediates. The biological effects of unrepaired AP sites are also discussed.
mesh_terms: D004247:DNA / Q000032:analysis* / Q000235:genetics / Q000528:radiation effects; D004249:DNA Damage; D045647:DNA Glycosylases; D011088:DNA Ligases / Q000378:metabolism; D004260:DNA Repair; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D004706:Endodeoxyribonucleases / Q000302:isolation & purification; D005720:Gamma Rays; D006898:Hydroxylamines; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D009699:N-Glycosyl Hydrolases / Q000302:isolation & purification / Q000378:metabolism; D009993:Osmium Tetroxide / Q000494:pharmacology; D010940:Plant Proteins / Q000302:isolation & purification; D051981:Uracil-DNA Glycosidase
chemical_list: D006898:Hydroxylamines; D010940:Plant Proteins; D004247:DNA; C005214:methoxyamine; D008741:Methyl Methanesulfonate; D004706:Endodeoxyribonucleases; D043223:Deoxyribonuclease IV (Phage T4-Induced); D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D011088:DNA Ligases; D009993:Osmium Tetroxide