Fate of a Synthetic Polynucleotide Directing Cell-Free Protein Synthesis I. Characteristics of Degradation

Tritiated-polyuridylie acid was degraded rapidly in extracts of Escherichia coli and degradation was not dependent on concomitant polyphenylalanine synthesis. Since a large portion of the polymer was degraded before appreciable polyphenylalanine was synthesized, the catalytic activity of the undegraded polyuridylic acid in directing protein synthesis was suggested. The predominant breakdown products were 5'-mononucleotide phosphates. Possible enzymatic routes of polyuridylic acid breakdown are discussed.