title: Regulation of proline degradation in Salmonella typhimurium.
abstract: The pathway for proline degradation in Salmonella typhimurium appears to be identical to that found in Escherichia coli and Bacillus subtilis. Delta(1)-Pyrroline-5-carboxylic acid (P5C) is an intermediate in the pathway; its formation consumes molecular oxygen. Assays were devised for proline oxidase and the nicotinamide adenine dinucleotide phosphate-specific P5C dehydrogenase activities. Both proline-degrading enzymes, proline oxidase and P5C dehydrogenase, are induced by proline and are subject to catabolite repression. Three types of mutants were isolated in which both enzymes are affected: constitutive mutants, mutants with reduced levels of enzyme activity, and mutants unable to produce either enzyme. Most of the mutants isolated for their lack of P5C dehydrogenase activity have a reduced level of proline oxidase activity. All the mutations are cotransducible. A genetic map of some of the mutations is presented. The actual effector of the pathway appears to be proline.
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D002874:Chromosome Mapping; D003124:Colorimetry; D004790:Enzyme Induction; D005827:Genetics, Microbial; D009154:Mutation; D009603:Nitroso Compounds; D010088:Oxidoreductases / Q000378:metabolism; D011392:Proline / Q000378:metabolism*; D012483:Salmonella Phages; D012486:Salmonella typhimurium / Q000201:enzymology / Q000302:isolation & purification / Q000378:metabolism*; D013053:Spectrophotometry; D014161:Transduction, Genetic
chemical_list: D009603:Nitroso Compounds; D011392:Proline; D010088:Oxidoreductases; D000594:Amino Acid Oxidoreductases