title: Enzymes of tryptophan biosynthesis in Serratia marcescens.
abstract: In Serratia marcescens, the tryptophan biosynthetic enzymes were formed coordinately. A number of tryptophan auxotrophs showed single biochemical lesions; several mutants showed pleiotropic effects. Sucrose density gradient centrifugation revealed an unique pattern of migration of the tryptophan biosynthetic enzymes. The repression response of the Serratia enzymes to exogenous tryptophan was fivefold more sensitive than that found in Escherichia coli. When this information is contrasted with the available information on the other Enterobacteriaceae, one is compelled to conclude that S. marcescens enjoys a rather marked evolutionary divergence from the other enteric organisms.
mesh_terms: D004794:Enzyme Repression; D005827:Genetics, Microbial; D006836:Hydro-Lyases / Q000378:metabolism; D007535:Isomerases / Q000378:metabolism; D008967:Molecular Biology; D009153:Mutagens / Q000494:pharmacology; D009154:Mutation; D009603:Nitroso Compounds / Q000494:pharmacology; D012706:Serratia marcescens / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D014166:Transferases / Q000378:metabolism; D014364:Tryptophan / Q000096:biosynthesis* / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D009153:Mutagens; D009603:Nitroso Compounds; D014364:Tryptophan; D014166:Transferases; D006836:Hydro-Lyases; D007535:Isomerases