title: Effects of 5-azacytosine in DNA on enzymic uracil excision.
abstract: PBS-2 phage DNA, which contains uracil in place of thymine, was used as substrate for both purified B. subtilis uracil-DNA glycosylase and a crude extract from M. luteus. Addition of [3H]5-azacytidine to the medium after phage infection resulted in substitution of 1.2% azacytosine for cytosine in DNA. Substrate DNA was also labeled with [14C]uracil. Neither enzyme preparation released tritiated bases from DNA. Analysis by S1 nuclease digestion show no increase in single-strandedness of the modified DNA. Enzymic release of uracil by the M. luteus extract was reduced by about 50% from the substituted substrate. By contrast, the rate of uracil excision by the purified enzyme was unaffected by the presence of DNA 5-azacytosine.
mesh_terms: D001374:Azacitidine / Q000378:metabolism*; D001412:Bacillus subtilis / Q000201:enzymology; D003596:Cytosine / Q000031:analogs & derivatives* / Q000378:metabolism; D045647:DNA Glycosylases; D004260:DNA Repair; D004279:DNA, Viral / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism; D007700:Kinetics; D008837:Micrococcus / Q000201:enzymology; D009699:N-Glycosyl Hydrolases / Q000378:metabolism*; D015719:Single-Strand Specific DNA and RNA Endonucleases; D014498:Uracil / Q000378:metabolism*; D051981:Uracil-DNA Glycosidase
chemical_list: D004279:DNA, Viral; C039854:5-azacytosine; D014498:Uracil; D003596:Cytosine; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase; D001374:Azacitidine