INHIBITION OF SYNTHESIS OF 5-S RIBOSOMAL RNA IN ESCHERICHIA COLI BY LEVALLORPHAN

Levallorphan (1.54·10-3 M) inhibits RNA biosynthesis by 70%, whereas the synthesis of protein is inhibited by 14%. The residual synthesis of tRNA under such conditions is greater by at least a factor of 2 than that of high molecular weight RNA. mRNA synthesis, on the contrary, seems to be only slightly inhibited or not at all. Levallorphan therefore exhibits effects similar to levorphanol. As the origin of 5-S RNA has been the subject of recent discussion we analyzed the extent of its synthesis in the presence of levallorphan. It has been found that 5-S RNA synthesis is inhibited by the drug at least as profoundly as high molecular weight RNA, a result which puts the 5-S RNA in the same class as the ribosomal RNA's and suggests that the same type of control mechanism regulates the synthesis of 5-S, 16-S and 23-S RNA's. © 1969.