actinomycin

n. [ From actinomyces, the genus of the organism in which they were first found. ] 1. any of various red antibiotics isolated from soil bacteria with a three-ring heterocyclic nucleus with an attached peptide chain. Actinomycin D is the most well-known and has been used to treat certain tumors. They act by binding to DNA and inhibiting the transcription of RNA. Their binding to DNA has been much studied.
Syn. -- actinomycin actinomycin C actinomycin F1 actinomycin D [ WordNet 1.5 ]