title: Human HeLa cell enzymes that remove phosphoglycolate 3'-end groups from DNA.
abstract: We have purified three chromatographically distinct human enzyme activities from HeLa cells, that are capable of converting bleomycin-treated DNA into a substrate for E. coli DNA polymerase I. The bleomycin-treated DNA substrate used in this study has been characterized via a 32P-postlabeling assay and shown to contain strand breaks with 3'-phosphoglycolate termini as greater than 95% of the detectable dose-dependent lesions. The purified HeLa cell enzymes were shown to be capable of removing 3'-phosphoglycolates from this substrate. Also 3'-phosphoglycolate removal and nucleotide incorporation were enzyme dependent. In addition, all three Hela cell enzymes have been determined to possess Class II AP endonuclease activity. The enzymes lack 3'----5' exonuclease activity and are, therefore, dissimilar to exonuclease III--an E. coli enzyme that can remove 3'-phosphoglycolate.
authors.affiliation: Department of Radiation Medicine, Vincent T. Lombardi Cancer Research Center, Georgetown University Medical Center, Washington DC 20007.
authors.forename: T A
authors.initials: TA
authors.lastname: Winters
authors.forename: M
authors.initials: M
authors.lastname: Weinfeld
authors.forename: T J
authors.initials: TJ
authors.lastname: Jorgensen
mesh_terms: D001761:Bleomycin / Q000494:pharmacology; D002845:Chromatography; D004247:DNA / Q000187:drug effects / Q000378:metabolism*; D004249:DNA Damage; D004256:DNA Polymerase I / Q000378:metabolism; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D015252:Deoxyribonucleases, Type II Site-Specific / Q000302:isolation & purification / Q000378:metabolism*; D004586:Electrophoresis; D004706:Endodeoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D006016:Glycolates / Q000378:metabolism*; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D010957:Plasmids / Q000235:genetics
chemical_list: D006016:Glycolates; D001761:Bleomycin; D004247:DNA; D004256:DNA Polymerase I; D004706:Endodeoxyribonucleases; D043223:Deoxyribonuclease IV (Phage T4-Induced); D015252:Deoxyribonucleases, Type II Site-Specific; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C013193:phosphoglycolate