Isolation and characterization Salmonella typhimurium mutants lacking a tripeptidase (peptidase T).

摘要: Abstract Salmonella typhimurium contains an enzyme, peptidase T, that hydrolyzes a variety of tripeptides. Specificity studies with activity stain after gel electrophoresis crude cell extracts showed T tripeptides containing N-terminal methionine, leucine, or phenylalanine. Little no could be detected against dipeptides, N-blocked C-blocked tripeptides, and tetrapeptides. Analysis reaction products by high-pressure liquid chromatography removes the amino acid from Mutants lacking were isolated screening microcultures grown in wells plastic microtitration plates for hydrolysis Met-Ala-Ser Met-Gly-Gly. Mutations (pepT) eliminate this enzyme found to phage P22 cotransducible purB at approximately 25 map units on S. map. Comparison growth properties mutant wild-type strains suggests does not function utilization provide acids during growth.