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a group of antibiotics formed by various actinomycetes. More than 100 actinomycins are known, and they are designated A, B, C, D, F, X, and so forth. Actinomycin was discovered in 1940 in a liquid culture medium of Streptomyces antibioticus. The molecular mass is around 1,200. Actinomycins can be separated from a liquid culture medium by extraction using butyl alcohol, acetone, and other solvents. They possess an antibiotic action against the gram-positive bacteria and certain fungi. Actinomycins are among the chromopeptides—that is, they consist of peptides and a chromophoric group (of red pigment) and therefore are bright red. All the actinomycins are highly toxic. An antitumoral action of actinomycins has been established in experiments on animals; however, they do not affect the most widely found forms of human cancer.
A. A. IMSHENETSKII