The inhibition of incorporation of leucine into protein of cell-free systems from rat liver and Escherichia coli by chlortetracycline

Gale & Folkes (1953) found that chlortetracycline inhibited protein synthesis in bacterial cultures whereas nucleic acid synthesis was apparently stimulated. Nikolov & Ilkov (1961) found that it reduced the incorporation in vivo of methionine into the proteins of a number of tissues in the rabbit, suggesting that the drug may also interfere with protein synthesis in the aniimal. Although much attention has been paid in recent years to the inhibition of protein biosynthesis by puromycin, chloramphenicol and streptomycin, there appears to be little information on the mode of action of chlortetracycline in inhibiting protein biosynthesis. The present work concerns the action of this drug on the incorporation of [14C]leucine into the various fractions of cell-free preparations from rat liver and Escherichia coli.