title: Action of a mammalian AP-endonuclease on DNAs of defined sequences.
abstract: An apurinic/apyrimidinic (AP) specific endonuclease from mouse plasmacytoma cells (line MPC-11), was observed to cleave apurinic sites in oligonucleotides 9, 11, 12, 39 and 40 nucleotides in length. However, the enzyme failed to cleave AP-sites in two oligonucleotides 7 nucleotides in length. The maximum rates of digestion observed on these short single-stranded DNA (ssDNA) fragments were approximately 1/30 of the rates observed on double-stranded DNA (dsDNA). In studies using the Maxam-Gilbert DNA sequencing analysis, apurinic sites in purine-rich regions were preferentially cleaved in dsDNA but not in ssDNA, indicating that the enzyme has a sequence preference on dsDNA. These results suggest that some sites on DNA might be more efficiently repaired than others.
authors: Laboratory of Biotechnology, University of Bergen, Norway.
authors: B I
authors: BI
authors: Haukanes
authors: D E
authors: DE
authors: Helland
authors: K
authors: K
authors: Kleppe
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D004706:Endodeoxyribonucleases / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D010954:Plasmacytoma / Q000201:enzymology; D013379:Substrate Specificity
chemical_list: D004277:DNA, Single-Stranded; D004247:DNA; D004706:Endodeoxyribonucleases; D043223:Deoxyribonuclease IV (Phage T4-Induced); D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase