Utilization ofd-amino acids bydadRmutants ofSalmonella typhimurium

✍ Scribed by Jadwiga Wild; Marcin Filutowicz; Tadeusz Kŀopotowski

• Publisher: Springer
• Year: 1978
• Tongue: English
• Weight: 601 KB
• Volume: 118
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00406077

✦ Synopsis

Utilization of D-amino acids being substrates of D-amino acid dehydrogenase of Salmonella typhimurium was examined. The experiments were done with wild type strains and the mutants dadA missing the enzyme activity and dadR in which its synthesis is released from catabolite repression. Growth on Dtryptophan, D-histidine and D-methionine used as precursors of the L-amino acids was faster when the respective auxotrophs carried dadR mutations. The dadR mutants grew faster when D-or L-alanine was present as a sole source of nitrogen. Experiments with D-amino acid dehydrogenase in vitro provided evidence that D-tryptophan is its substrate with a very low affinity to the dehydrogenase.