title: Identification and characterization of d-arabinose reductase and d-arabinose transporters from Pichia stipitis.
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/Kmvalue with d-arabinose (1.27 min-1mM-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.
authors.affiliation: a Department of Bioscience , Graduate School of Agriculture, Ehime University , Matsuyama , Japan.|b Center for Marine Environmental Studies , Ehime University , Matsuyama , Japan.
authors.forename: Seiya
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: a Department of Bioscience , Graduate School of Agriculture, Ehime University , Matsuyama , Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Utsumi
authors.affiliation: c Graduate School of Agriculture , Kyoto University , Kyoto , Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sawayama
authors.affiliation: a Department of Bioscience , Graduate School of Agriculture, Ehime University , Matsuyama , Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Watanabe
keywords: -arabinose; -xylose reductase; pentose metabolism; sugar transporter