Proflavine inhibition of protein synthesis.

Prcflavine, in the range of 5 x 1OU5 M, markedly inhibited prctein synthesis in a subcellular rat liver system. With native messenger ribonucleic acids, leucine incorporation was inhibited more than phenylalanine incorporation. In the presence of polyuridylate, however, phenylalanine incorporation was inhibited more than leucine incorporation. Reversal studies indicated that excess transfer ribonucleic acid and, to a lesser extent, excess microsomes, but not polyuridylate, overcame proflavine inhibition. Specific asss.ys indicated that the drug inhibited both the synthesis of phenylalanyl transfer ribonucleic acid as well as the transfer reaction. These results suggest that the biological properties cf the aminoacridines may be due not only to their ability to react with deoxyribonucleic acid, but also to their ability to form complexes with transfer ribonucleic acid and thereby directly interfere with protein synthesis.