[Pool of free amino acids in mycelium and culture fluid of Streptomyces galbus (F) subsp. achromogenes 695, a strain producing actinomycin complex and its variants].

Free amino acids in the mycelium and culture fluid of Streptomyces galbus (F) subsp. achromogenes 695 and its active and inactive variants were comparatively studied. It was found that the amino acid pool in the mycelium of the highly productive variant was 14 per cent higher than that of the initial strain and 40 per cent higher than that of the inactive variant. Even so, the highest amounts of the synthesized protein in the three strains were about the same. The free amino acid composition of the mycelium of the active antibiotic-producing strains and the inactive variant was shown to be the same and included all the investigated 16 amino acids. Glutamic acid was the main amino acid. The contents of alanine, serine and valine were comparatively high. The contents of methionine, histidine and phenylalanine were the lowest. It was shown that the quantities of the amino acids or their precursors participating in the construction of the antibiotic molecule were to a higher extent determined by the strain development and growth rate than by the actinomycin biosynthesis. The qualitative and quantitative composition of the amino acid pool in the culture fluid of the active strains was inferior to that in the inactive variant.