title: The incomplete denaturation of DNA in N,N-dimethyl formamide.
abstract: In this paper we show that the extent of DNA denaturation achieved by dialysis against N,N-dimethyl formamide depends on both the source of DNA and the buffer used. The stability against denaturation increases with the guanine plus cytosine content. The base sequence also plays a minor role. This behavior is due to differences in the solubility of DNA in the denaturing solvent. The DNAs with a high guanine-cytosine content have a lower solubility in dimethyl formamide and this fact results in a higher stability against denaturation. As a practical consequence, in order to achieve complete denaturation of DNA by dialysis against dimethyl formamide, it is necessary to start with DNA dissolved in a buffer of low ionic strength, preferably below 10(-3) M.
mesh_terms: D002021:Buffers; D003596:Cytosine / Q000032:analysis; D004247:DNA; D004126:Dimethylformamide; D004355:Drug Stability; D006147:Guanine / Q000032:analysis; D007700:Kinetics; D008722:Methods; D009691:Nucleic Acid Denaturation; D009994:Osmolar Concentration; D012964:Sodium; D013045:Species Specificity; D013696:Temperature
chemical_list: D002021:Buffers; D006147:Guanine; D004126:Dimethylformamide; D003596:Cytosine; D004247:DNA; D012964:Sodium