A group of tuberculostatic peptide antibiotics called tuberactinomycin (TUM) was found in the culture broth of Streptomyces griseover-ticillatus var. tuberacticus. TUM-A and B were first isolated from the broth filtrate, and a mutant prepared by treatment of the original microorganism with nitrosoguanidine produced two similar antibiotics termed TUM-N and O. Of these four congeners, TUM-B was identical with the previously known antibiotic, viomycin. The structures of two new amino acids isolated as components of TUM-A, i. e. γ-hydroxy-β-lysine and tuberactidine, were determined as reported already. On the basis of the extreme similarity of amino acid compositions as well as chemical and physical properties of four antibiotics, it is suspected that all of the peptides may have the same amino acid sequence, being only differenciated each other in existence of hydroxyl groups on residues of β-lysine and guanidinoamino acid. The chemical studies on partial hydrolyzates of these congeners suggested a possibility of a new total structure different from those proposed by other workers for viomycin, i.e. TUM-B. Finally, the X-ray analysis was performed on the crystal of TUM-O-1HC1・2HBr・3H_2O. Thus the total structure of this compound was determined evidently.
