Identification and characterization of d-arabinose reductase and d-arabinose transporters from Pichia stipitis |
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Authors: | Seiya Watanabe Yuki Utsumi Shigeki Sawayama Yasuo Watanabe |
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Affiliation: | 1. Department of Bioscience, Graduate School of Agriculture, Ehime University, Matsuyama, Japan;2. Center for Marine Environmental Studies, Ehime University, Matsuyama, Japan;3. Graduate School of Agriculture, Kyoto University, Kyoto, Japan |
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Abstract: | d-xylose and l-arabinose are the major constituents of plant lignocelluloses, and the related fungal metabolic pathways have been extensively examined. Although Pichia stipitis CBS 6054 grows using d-arabinose as the sole carbon source, the hypothetical pathway has not yet been clarified at the molecular level. We herein purified NAD(P)H-dependent d-arabinose reductase from cells grown on d-arabinose, and found that the enzyme was identical to the known d-xylose reductase (XR). The enzyme activity of XR with d-arabinose was previously reported to be only 1% that with d-xylose. The kcat/Km value with d-arabinose (1.27 min?1 mM?1), which was determined using the recombinant enzyme, was 13.6- and 10.5-fold lower than those with l-arabinose and d-xylose, respectively. Among the 34 putative sugar transporters from P. stipitis, only seven genes exhibited uptake ability not only for d-arabinose, but also for d-glucose and other pentose sugars including d-xylose and l-arabinose in Saccharomyces cerevisiae. |
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Keywords: | Pichia stipitis pentose metabolism smallcaps smallerCapital" >d-arabinose smallcaps smallerCapital" >d-xylose reductase sugar transporter |
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