The presence of N-(purin-6-ylcarbamoyl)threonine in transfer ribonucleic acid species whose codons begin with adenine.

Adenine Amino Acyl-tRNA Synthetases Arginine Asparagine Benzoates Carbamates/analysis Carbon Isotopes Chemical Phenomena Chemistry Chromatography, DEAE-Cellulose Electrophoresis, Paper Escherichia coli/analysis,enzymology Genetic Code Glycolates Isoleucine Leucine Lysine Methionine Purine Nucleotides/analysis RNA, Bacterial/analysis RNA, Transfer/analysis Serine Succinimides Threonine/analysis Tritium

Benzoates Carbamates Carbon Isotopes Glycolates Purine Nucleotides RNA, Bacterial Succinimides Isoleucine Tritium Threonine Serine Asparagine RNA, Transfer Arginine Methionine Amino Acyl-tRNA Synthetases Leucine Adenine Lysine