title: Unusual growth characteristics of a methionine-cyano-B12 auxotroph of Escherichia coli.
abstract: Escherichia coli K-12, strain AB1172, substrain 2276, a methionine(-)-cyano-B(12) (-) auxotroph grew poorly when placed in a medium containing optimal levels of cyano-B(12) and suboptimal amounts of l-methionine. A marked depression of N(5,10)-methylene-H(4)-folate reductase was observed in the inhibited cells, although no significant alterations in other enzymes involved in the metabolism of N(5,10)-methylene-H(4)-folate were observed. Guanosine was effective in preventing the growth inhibition.
mesh_terms: D000225:Adenine / Q000494:pharmacology; D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D001120:Arginine / Q000494:pharmacology; D002247:Carbon Isotopes; D004926:Escherichia coli / Q000254:growth & development*; D005492:Folic Acid / Q000378:metabolism; D006639:Histidine / Q000494:pharmacology; D008025:Ligases / Q000378:metabolism; D008715:Methionine / Q000378:metabolism* / Q000494:pharmacology; D009154:Mutation; D009705:Nucleosides / Q000494:pharmacology; D010088:Oxidoreductases / Q000378:metabolism; D013831:Thiamine / Q000494:pharmacology; D014166:Transferases / Q000378:metabolism; D014805:Vitamin B 12 / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D009705:Nucleosides; D006639:Histidine; D005492:Folic Acid; D001120:Arginine; D008715:Methionine; D010088:Oxidoreductases; D000429:Alcohol Oxidoreductases; D014166:Transferases; D008025:Ligases; D000225:Adenine; D014805:Vitamin B 12; D013831:Thiamine