Identification of an L-arabinose reductase gene in Aspergillus niger and its role in L-arabinose catabolism

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    36 Citations (Scopus)

    Abstract

    The first enzyme in the pathway for L-arabinose catabolism in eukaryotic microorganisms is a reductase, reducing L-arabinose to L-arabitol. The enzymes catalyzing this reduction are in general nonspecific and would also reduce D-xylose to xylitol, the first step in eukaryotic D-xylose catabolism. It is not clear whether microorganisms use different enzymes depending on the carbon source. Here we show that Aspergillus niger makes use of two different enzymes. We identified, cloned, and characterized an L-arabinose reductase, larA, that is different from the D-xylose reductase, xyrA. The larA is up-regulated on L-arabinose, while the xyrA is up-regulated on D-xylose. There is however an initial up-regulation of larA also on D-xylose but that fades away after about 4 h. The deletion of the larA gene in A. niger results in a slow growth phenotype on L-arabinose, whereas the growth on D-xylose is unaffected. The L-arabinose reductase can convert L-arabinose and D-xylose to their corresponding sugar alcohols but has a higher affinity for L-arabinose. The Km for L-arabinose is 54 ± 6 mM and for D-xylose 155 ± 15 mM.

    Original languageEnglish
    Pages (from-to)23622-23628
    Number of pages7
    JournalJournal of Biological Chemistry
    Volume285
    Issue number31
    DOIs
    Publication statusPublished - 30 Jul 2010
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Aspergillus niger
    • pentose catabolism
    • regulation of pentose catabolism
    • aldose reductase
    • EC.1.1.1.21

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