The yjjN of E. coli codes for an l-galactonate dehydrogenase and can be used for quantification of l-galactonate and l-gulonate

Joosu Kuivanen (Corresponding Author), Peter Richard

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Escherichia coli is able to utilize l-galactonate as a sole carbon source. A metabolic pathway for l-galactonate catabolism is described in E. coli, and it is known to be interconnected with d-galacturonate metabolism. The corresponding gene encoding the first enzyme in the l-galactonate pathway, l-galactonate-5-dehydrogenase, was suggested to be yjjN. However, l-galactonate dehydrogenase activity was never demonstrated with the yjjN gene product. Here, we show that YjjN is indeed an l-galactonate dehydrogenase having activity also for l-gulonate. The Km and kcat for l-galactonate were 19.5 ± 0.6 mM and 0.51 ± 0.03 s-1, respectively. In addition, YjjN was applied for a quantitative detection of the both of these substances in a coupled assay. The detection limits for l-galactonate and l-gulonate were 1.65 and 10 µM, respectively.
Original languageEnglish
Pages (from-to)1829-1835
Number of pages7
JournalApplied Biochemistry and Biotechnology
Issue number7
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed



  • YjjN
  • l-galactonate-5-dehydrogenase
  • l-galactonate
  • l-gulonate
  • d-galacturonate
  • E.coli

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