Fractionation of amino acid acceptor ribonucleic acid. II

1. 1. Further data are reported on the fractionation of brewers' yeast and Escherichia coli amino-acyl transfer RNA (s-RNA) by chromatography on heated DEAE-cellulose columns and by chromatography on Sephadex G-25 partition columns. 2. 2. Elution profiles of brewers' yeast and E. coli s-RNA from both DEAE-cellulose and Sephadex partition columns are compared. Considerable differences were found in the elution profiles for yeast and E. coli s-RNA on DEAE-cellulose columns. 3. 3. Elution positions of species of s-RNA accepting single amino acids were determined and the order of elution of individual species of s-RNA was compared. The elution positions and the order of elution differed in the two procedures. 4. 4. With these methods species of s-RNA accepting a single amino acid have been purified, and major and minor s-RNA species accepting a single amino acid have been detected. 5. 5. The elution positions and hence properties of yeast s-RNA species accepting a particular amino acid often differ from those of E. coli s-RNA species accepting the same amino acid. 6. 6. The number of yeast s-RNA species accepting a particular amino acid often differs from that found for E. coli. This confirms earlier reports of species specificity of s-RNA.