title: Thermal denaturation of DNA from bromodeoxyuridine substituted cells.
abstract: The thermal denaturation of DNA from cell lines extensively substituted with bromodeoxyuridine has been examined spectrophotometrically over a wide range in ionic strength and by thermal elution from hydroxyapatite columns. BrdU substitution stabliizes DNA at all ionic strengths between 7.5 mM and 1350 mM potassium ion concentration, although a plot of log ionic strength vs Tm deviates from linearity above 150 mM. This nonlinearity is most pronounced with BrdU-substituted DNAs, resulting in a lowered delta Tm between unsubstituted and substituted DNA with increasing ionic strength. DMSO is shown to decrease the Tm of both unsubstituted and BrdU-substituted DNA equally, at a rate of .5 degrees C per 1% DMSO.
mesh_terms: D001973:Bromodeoxyuridine / Q000378:metabolism*; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004355:Drug Stability; D006358:Hot Temperature; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009994:Osmolar Concentration; D011119:Polynucleotides; D011188:Potassium; D013329:Structure-Activity Relationship
chemical_list: D011119:Polynucleotides; D004247:DNA; D001973:Bromodeoxyuridine; D011188:Potassium