The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by (13)C-labeling experiments.
Uniformly (13)C labeled glucose was fed to a lactic acid bacterium growing on a defined medium supplemented with all proteinogenic amino acids except glutamate. Aspartate stemming from the protein pool and from the extracellular medium was enriched with (13)C disclosing a substantial de novo biosynthesis of this amino acid simultaneous to its uptake from the growth medium and a rapid exchange flux of aspartate over the cellular membrane. Phenylalanine, alanine, and threonine were also synthesized de novo in spite of their presence in the growth medium.
Jensen
Niels Bang Siemsen
NB
Center for Process Biotechnology, Department of Biotechnology, Building 223, Technical University of Denmark, DK-2800 Lyngby, Denmark.
Christensen
Bjarke
B
Nielsen
Jens
J
Villadsen
John
J
D000409:Alanine / Q000096:biosynthesis / Q000493:pharmacokinetics; D000596:Amino Acids / Q000096:biosynthesis* / Q000493:pharmacokinetics*; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism*; D018533:Biomass; D002462:Cell Membrane / Q000378:metabolism; D003198:Computer Simulation; D003470:Culture Media; D008401:Gas Chromatography-Mass Spectrometry; D018698:Glutamic Acid / Q000378:metabolism; D007553:Isotope Labeling / Q000379:methods; D013294:Lactococcus lactis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008954:Models, Biological; D008956:Models, Chemical; D010649:Phenylalanine / Q000096:biosynthesis / Q000493:pharmacokinetics; D013912:Threonine / Q000096:biosynthesis / Q000493:pharmacokinetics
D000596:Amino Acids; D003470:Culture Media; D013912:Threonine; D001224:Aspartic Acid; D018698:Glutamic Acid; D010649:Phenylalanine; D000409:Alanine