Abstract
The use of tRNA affinity columns for the purification of aminoacyl-tRNA synthetases was investigated. A purification method for valyl-tRNA synthetase from Bacillus stearothermophilus is described that uses two affinity columns, one containing the pure cognate tRNA, and the other containing all tRNA species except the cognate tRNA. A method for the rapid preparation of the two columns was developed, which does not require prior isolation of cognate tRNA but makes use of the ability of the target synthetase to select its cognate tRNA. The usefulness of tRNA columns is compared with that of affinity columns derived from the aminoalkyladenylate reported in the preceding paper [Clarke & Knowles (1977) Biochem J. 167, 405-417].