Isolierung von serinspezifischen transfer-ribonucleinsäure-fraktionen

Soluble RNA was isolated from brewer's yeast; on the average 30–35 g were obtained from 50 kg. 350 mg of a serine transfer-RNA fraction were isolated from 32 g of soluble RNA by several subsequent countercurrent distributions in the tri-n-butylamin system (Fig. 1, Table I). The serine transfer-RNA fraction (31 mμmoles serine/mg RNA; less than 1 % of acceptor activity for other amino acids was detected) contained two serine transfer-RNA chains. The nucleotide composition of the serine transfer-RNA fraction was determined (Fig. 3, Table II). In a second series of countercurrent distributions the two serine transfer-RNA's were separated (Fig. 2) from each other and partially purified.