Chemically Modified Phenylalanine Transfer Ribonucleic Acid from Yeast. Synthesis and Properties of tRNAPhe-C-C s A and the Effect of Adenosine 5'-O-(1-Thiotriphosphate) on the Activation of Phenylalanine

Adenosine 5′-O-(1-thiotriphosphate) was incorporated in tRNAPhe-C-C by C-C-A pyrophosphorylase. The resulting tRNA Phe-C-C s̄ A could be charged with phenylalanine by aminoacyl-tRNA synthetase and pyrophosphorolyzed with C-C-A pyrophosphorylase. Degradation with snake venom phosphodiesterase, however, was markedly reduced. Adenosine 5′-O-(1-thiotriphosphate) did not substitute for ATP in the activation of phenylalanine by aminoacyl-tRNA synthetase, but was a competitive inhibitor.