title: Overproduction of Salmonella typhimurium peptidase T.
abstract: Pseudorevertants able to use L-leucyl-L-leucyl-L-leucine as a leucine source have been isolated from a Salmonella typhimurium strain carrying stable (nonreverting) mutations in pepN, pepA, and pepB. These strains carry mutations at a locus pto (peptidase T overproducer) tightly linked to pepT that cause an elevated expression of the tripeptidase peptidase T. An F' episome carrying the pto and pepT loci has been constructed and used to show that the pto mutations are cis dominant. Expression of beta-galactosidase from a Mu d1(Apr lac) insertion in pepT is increased by pto mutations. The pto mutations, therefore, define a site affecting the transcription of pepT.
mesh_terms: D000626:Aminopeptidases / Q000235:genetics*; D002874:Chromosome Mapping; D004251:DNA Transposable Elements; D009154:Mutation; D009842:Oligopeptides / Q000378:metabolism; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D013045:Species Specificity; D013329:Structure-Activity Relationship; D013696:Temperature; D014161:Transduction, Genetic
chemical_list: D004251:DNA Transposable Elements; D009842:Oligopeptides; D000626:Aminopeptidases; C039576:peptidase T; C036671:leucyl-leucyl-leucine