Browsing by Author "Spencer, M."
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Item Hydroxyapatite for chromatography III. Cation and pH effects on fractionation of tRNA for crystallization(1978) Spencer, M.; Neave, E.J.; Webb, N.L.Hydroxyapatite (HA) prepared by a new method was applied to the rapid fractionation of E. coli tRNA. Elution at 5° with sodium or potassium phosphate, at two pH values, showed that the order of elution depended on both the buffer cation and the pH. These variations, and that due to temperature, were attributed to changes in tRNA structure which altered the pattern of exposed phosphate charges. The molarity at which tRNA started to elute was lowest at high pH, suggesting that HPO4^2-- was more effective than H2PO4- in displacing tRNA from HA. tRNA fractions from a column of benzoylated DEAE-cellulose were fractionated on HA to give nine species of purity 850-1600 pmoles per A260 unit, four of which could be crystallized.