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| | RedOrbit - Science - Arabidopsis POLYOL TRANSPORTER5, a New Member of the Monosaccharide Transporter-Like Superfamily, ... (Site not responding. Last check: 2007-10-09) |
 | | Linear polyols, such as sorbitol or mannitol, are found in high concentrations in the phloem sap of plants from several families, such as Rosaceae, Apiaceae, or Plantaginaceae (Zimmermann and Ziegler, 1975). |
 | | After their synthesis in leaves by sugar phosphate reductases and polyol phosphate phosphatases, linear polyols are loaded into the phloem by polyol-H+ symporters that accumulate their substrates to concentrations of several hundred millimolar (Zimmermann and Ziegler, 1975; Lohaus and Fischer, 2002; G. Lohaus, unpublished data). |
 | | All plant plasma membrane sugar and polyol transporters of the 12 transmembrane helix-type (STPs, PLTs, and SUCs) were shown to be energy-dependent H+-symporters and to be voltage dependent (Williams et al., 2000; Ramsperger-Gleixner et al., 2004). |
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