title: Studies of etamycin biosynthesis employing short-term experiments with radiolabeled precursors.
abstract: The biosynthesis of etamycin by Streptomyces griseoviridus was investigated with the precursors, 14C-L-leucine and 14CH3-L-methionine, during short-term incubations. Both radiosotopes are rapidly incorporated into the antibiotic without significant lag. D-Leucine,but not L-leucine,inhibits etamycin formation. The kinetics of incorporation of 14C-L-leucine as well as the inhibitor studies suggest that L-leucine is the direct precursor of theD-enantiomerpresent in the antibiotic peptide. Chloramephenicol has been shown to inhibit protein synthesis by S. griseoviridus without reduction of etamycin formation, indicating that a non-ribosomal mechanism of synthesis is involved in etamycin biogenesis. When L-ethionine was employed, both the formation of antibiotic and protein were blocked.
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis / Q000096:biosynthesis*; D001412:Bacillus subtilis / Q000187:drug effects; D001426:Bacterial Proteins / Q000096:biosynthesis; D002701:Chloramphenicol / Q000494:pharmacology; D005001:Ethionine / Q000494:pharmacology; D007930:Leucine / Q000378:metabolism / Q000494:pharmacology; D008715:Methionine / Q000378:metabolism; D010456:Peptides, Cyclic / Q000096:biosynthesis; D013302:Streptomyces / Q000187:drug effects / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010456:Peptides, Cyclic; D002701:Chloramphenicol; D008715:Methionine; D007930:Leucine; D005001:Ethionine