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Literature summary for extracted from

  • Chen, I.C.; Thiruvengadam, V.; Lin, W.D.; Chang, H.H.; Hsu, W.H.
    Lysine racemase: a novel non-antibiotic selectable marker for plant transformation (2010), Plant Mol. Biol., 72, 153-169.
    View publication on PubMed


Application Comment Organism
biotechnology enzyme is a novel non-antibiotic selectable marker for plant transformation uncultured bacterium


Cloned (Comment) Organism
transformation of the lyr gene in Nicotiana benthamiana and Arabidopsis thaliana plants by means of Agrobacterium tumefaciens strains LBA4404 and GV3101, transgenic plants produce normal roots that penetrate into the selection medium and are healthy, the Lyr gene is found to be expressed as a protein in all the transgenic lines uncultured bacterium

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
determined by SDS-PAGE and Western Blot analysis uncultured bacterium

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
L-lysine uncultured bacterium
D-lysine D-lysine is used by the transgenic plants as nitrogen source r


Organism UniProt Comment Textmining
uncultured bacterium C7ACH5 from soil, the lyr gene may have recently evolved from Escherichia coli N-acetyl-gamma-glutamyl-phosphate reductase and Deinococcus radiodurans N-acyl amino acid racemase, the partial regions of both enzymes might have been combined to evolve a novel enzyme, in which the new catalytic sites are created for catalyzing the racemization of lysine

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
additional information
enzyme is incubated in 1 ml of reaction mixture containing 50 mM Tris-HCl (pH 8.0), 2 mM cobalt chloride and 10 mM L- or D-lysine at 30°C, Lyr activities in 4 week old wild type and transgenic tobacco plants are determined, the specific activity of Lyr in the transgenic T2 plants selected on L-lysine ranges from 0.77 to 1.06 mU/mg protein, although transgenic plants exhibit considerable variation in enzyme activities, no phenotypic dissimilarities associated with L-lysine selection are found, suggesting that the Lyr gene as a selectable marker could be effective over a range of expression levels uncultured bacterium

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
uncultured bacterium D-lysine D-lysine is used by the transgenic plants as nitrogen source r


Synonyms Comment Organism
uncultured bacterium
lysine racemase
uncultured bacterium

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
assay at uncultured bacterium

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
assay at uncultured bacterium


Organism Comment Expression
uncultured bacterium to investigate the effect of Lyr expression on the amino acid profile of the host cells, the composition of free amino acids in the leaves of wild-type and transgenic tobacco plants is determined, the results reveal a substantial 40fold and a marginal 4fold increase of free L-aspartate content in the wild-type and transgenic plants, respectively, grown on L-lysine medium as compared to plants grown on medium containing D-lysine or without lysine supplement additional information