Trace nucleotides in certain ribonucleic acids from yeast.

A number of trace nucleotides are reported to be present in ribonucleic acids from various sources. Cohn (I) and Davis and Allen (2) have described a nucleotide in yeast ribonucleic acids, the nucleoside of which has recently been identified as 5ribosyluracil.’ Littlefield and Dunn (3) have found small amounts of thymine, 2-methyladenine, N6-methyladenine2 (6methylaminopurine), and Ne-dimethyladenine (6-dimethylaminopurine) in ribonucleic acids from yeast, several bacterial species, and wheat germ. The latter two bases were also found in the ribonucleic acids of rat liver microsomes. These bases were shown to have been present originally as nucleotides in 3’) 5’phosphodiester linkage in the ribonucleic acids of E. coli. Adler et cd. (4) have detected N6-methyladenine, N2-methylguanine (2methylamino-6-hydroxypurine) and one-methylguanine in acid hydrolysates of commercial preparations of yeast ribonuclcic acids, and Kemp and Allen (5) have described three unknown nucleotide components that are present in minor amounts in ribonucleic acids from dog pancreas. This paper reports the separation of four trace nucleotides, in addition to the one previously described (1, 2) from a yeast ribonucleic acid fraction that is soluble in 1 1% sodium chloride. This fraction is ordinarily discarded during the preparation of yeast ribonucleic acids by the procedure of Crestfield et al (6). The identity of three of the trace nucleotides, and certain characteristics of these nucleotides as well as of the ribonucleic acid fraction in which they are found, are reported.