During the coming year it is planned to carry out research in the following areas: 1. Continue studies on the directed biosynthesis of actinomycin including compounds produced with cis or trans-4-chloroproline, azetidine-2-carboxylic acid or pipecolic acid. 2. Examine the properties and chemical nature of the novel amino acid components of the actinomycins produced by Micromonospora floridensis. 3. Radioisotopic experiments will be conducted to explore the biogenetic precursors of the novel amino acids in these actinomycins. 4. Carry out biochemical and genetic studies to determine the role of tryptophan and its metabolism in the biosynthesis of the actinomycin, chromophore, actinocin. 5. Study the cell-free synthesis of actinomycin as well as the constituent amino acids (D-valine, Sarcosine, N-methylvaline). 6. Investigate the relationship of actinomysin formation to the growth and differentiation of the producing organism. BIBLIOGRAPHIC REFERENCES: Katz, E. and Demain, A.L. The peptide antibiotics of Bacillus species: Chemistry biogenesis and possible functions. Bacteriol. Reviews, 1977. In press. Williams, W.K. and Katz, E. Development of a chemically-defined medium for the synthesis of actinomycin D by Streptomyces parvulus. Antimicrobial Agents and Chemotherapy, 1977. In press.