Abstract
Antlermicin A is a new antitumor antibiotic which inhibits growth of Bacillus subtilis strongly. As uridine incorporation into the TCAinsoluble fraction of Bacillus subtilis was inhibited severely, it was suggested that antlermicin A inhibited RNAsynthesis. Both syntheses ofuridine and uridine nucleotides were not inhibited and furthermore, accumulation of uridine nucleotides was observed in the presence of antlermicin A. The RNApolymerase reaction in a cell-free system was inhibited significantly only at a high concentration of this antibiotic.