Separation of transfer ribonucleic acid by sepharose chromatography using reverse salt gradients

The transfer ribonucleic acids of Escherichia coli bind to unsubstituted Sepharose in the presence of high concentrations of ammonium sulfate at pH 4.5. Transfer RNA species are eluted individually from the Sepharose by a gradient from high to low concentrations of ammonium sulfate; leucine tRNA is fractionated into five isoaccepting species. The order of elution of these isoaccepting species differs from that seen with reverse phase chromatography. By means of only these two procedures, one isoaccepting species of leucine tRNA can be purified to apparent homogeneity. Isoaccepting tRNA species for 9 amino acids have been resolved. This established the general utility of this chromatographic system for the separation and purification of specific isoaccepting transfer RNAs.