III. The RNA component of aminoacyl-tRNA synthetase complexes isolated from mouse liver. Absence of amino acid accepting activity.

A method is described which permits the simultaneous isolation and separation of insoluble aminoacyl-tRNA synthetase protein - RNA complexes containing high specific synthetase activity, and soluble tRNA which retains 25% to 50% of its specific amino acid accepting activity. A possible amino acid accepting activity of the RNA part of the insoluble aminoacyl-tRNA synthetase protein - RNA complex was investigated by assaying the unchanged complex and the RNA obtained after dissociation from the protein part of the synthetase complex. No amino acid accepting activity was found.