CHROMATOGRAPHY OF NUCLEIC ACIDS ON HYDROXYAPATITE .I. CHROMATOGRAPHY OF NATIVE DNA

Using the stepwise elution technique, native doublestranded DNA is eluted by 0.20 M and 0.25 M potassium phosphate buffer, pH 6.8: occasionally minor fractions are eluted by 0.30 M and 0.50 M phosphate. Rechromatography experiments showed that the multipeak pattern obtained is an artifact. Indeed, when using the gradient elution technique all native DNA preparations investigated in the present work were eluted as single peaks. A different chromatographic behaviour was shown by singlestranded DNA from Φ X174 phage, yeast mitochondrial DNA, and glucosylated DNA. No significant changes in the physical, chemical or biological properties of native DNA are caused by the adsorption-elution process. The native DNA's studied here were not fractionated by hydroxyapatite columns as far as their base composition and biological properties are concerned. A very limited extent of fractionation on the basis of molecular weight was observed. It was shown that elution can be performed at constant ionic strength and in the presence of a variety of organic molecules. © 1969.