Intracellular feruloylation of arabinoxylan in wheat: evidence for feruloyl-glucose as precursor.
Incorporation of [(3)H]arabinose and [(14)C]ferulic acid into soluble and polymeric fractions from suspension-cultured wheat (Triticum aestivum L.) cells and the corresponding extracellular medium was studied. The major part of these products was identified as arabinoxylan and two proteins of 40 and 100 kDa. The time course suggests an intracellular synthesis of feruloylated arabinoxylan with feruloyl-glucose as substrate. In contrast, synthesis of feruloylated proteins appears to occur with feruloyl-CoA as precursor. Intracellular formation of ferulic acid dimers is limited to 8,5'-diferulic acid, while other dimers appear to be formed extracellularly. [(3)H]Arabinose was incorporated into polymeric material in both the cellular and in the medium fraction while [(14)C]ferulic was only found in polymers from the cellular fraction, indicating synthesis of both feruloylated and non-feruloylated arabinoxylan by the cells.
Obel
Nicolai
N
Plant Biochemistry Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, 1871 Frederiksberg C, Copenhagen, Denmark.
Porchia
Andrea Celia
AC
Scheller
Henrik Vibe
HV
D001089:Arabinose / Q000378:metabolism; D002250:Carbon Radioisotopes; D002473:Cell Wall / Q000378:metabolism; D002478:Cells, Cultured; D020374:Chromatography, Micellar Electrokinetic Capillary; D003373:Coumaric Acids / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases; D005947:Glucose / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D014908:Triticum / Q000378:metabolism*; D014316:Tritium / Q000378:metabolism; D014990:Xylans / Q000378:metabolism*; D014994:Xylose / Q000096:biosynthesis / Q000378:metabolism; D014995:Xylosidases / Q000378:metabolism
D002250:Carbon Radioisotopes; D003373:Coumaric Acids; D010940:Plant Proteins; D014990:Xylans; D014316:Tritium; C085118:arabinoxylan; D014994:Xylose; C004999:ferulic acid; D001089:Arabinose; D006026:Glycoside Hydrolases; D014995:Xylosidases; C019713:alpha-N-arabinofuranosidase; D043364:Endo-1,4-beta Xylanases; D005947:Glucose