title: Production of methionine-excreting mutants of Streptomyces fradiae.
abstract: Methionine-excreting mutant strains of Streptomyces fradiae ATCC 10745, producedby exposure to N-methyl-N'-nitro-N-nitrosoguanidine, were selected on the basisof ethionine-resistance and ability to support the growth of an auxotroph which requiredmethionine or methionine precursors. When acid hydrolysates of dehydrated liquid cultures were analyzed for amino acid content, one of the mutants had produced 268% more methionine that the parental strain. To obtain an accurate analysis of methionine content, it was necessary to determine the amount of diaminopimelic acid which had been synthesized. This compound appeared in eluates during column chromatography at about the same time as methionine, and its presence increased apparent methionine concentrations by 25 to40%.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D003960:Diaminopimelic Acid / Q000096:biosynthesis; D008715:Methionine / Q000378:metabolism*; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D009153:Mutagens; D009154:Mutation; D009604:Nitrosoguanidines / Q000494:pharmacology*; D013302:Streptomyces / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D009153:Mutagens; D009604:Nitrosoguanidines; D008769:Methylnitronitrosoguanidine; D003960:Diaminopimelic Acid; D008715:Methionine