The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by (13)C-labeling experiments

Biotechnol Bioeng. 2002 Apr 5;78(1):11-6. doi: 10.1002/bit.10211.

Abstract

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.

MeSH terms

  • Alanine / biosynthesis
  • Alanine / pharmacokinetics
  • Amino Acids / biosynthesis*
  • Amino Acids / pharmacokinetics*
  • Aspartic Acid / chemistry
  • Aspartic Acid / metabolism*
  • Biomass
  • Cell Membrane / metabolism
  • Computer Simulation
  • Culture Media
  • Gas Chromatography-Mass Spectrometry
  • Glutamic Acid / metabolism
  • Isotope Labeling / methods
  • Lactococcus lactis / genetics
  • Lactococcus lactis / growth & development
  • Lactococcus lactis / metabolism*
  • Models, Biological*
  • Models, Chemical
  • Phenylalanine / biosynthesis
  • Phenylalanine / pharmacokinetics
  • Threonine / biosynthesis
  • Threonine / pharmacokinetics

Substances

  • Amino Acids
  • Culture Media
  • Threonine
  • Aspartic Acid
  • Glutamic Acid
  • Phenylalanine
  • Alanine