Isolation, purification, and characterization of pipecolic acid-containing actinomycins, Pip 2, Pip 1 , and Pip 1 .

Streptomyces antibioticus synthesizes several new actinomycins when DL-pipecolic acid is provided in the culture medium. Three of the compounds (Pip 2, Pip lar, and Pip Ifi) were isolated, purified, and characterized. Amino acid hydrolysates revealed that these antibiotics contain threonine, valine, sarcosine, and N-methylvaline but differ from actinomycins normally synthesized in the imino acid site of the molecule. The data reveal that: actinomycin Pip 2 contains 2 residues of pipecolic acid, actinomycin Pip lp possesses 1 residue each of pipecolic acid and proline, and actinomycin Pip la! contains pipecolic acid and 4-oxopipecolic acid per mole of actinomycin. 4-Oxopipecolic acid is a normal constituent of a number of peptide antibiotics, e.g. ostreogrycin, vernamycin Ba, and staphylomycin.