Arabinoxylan biosynthesis: Identification and partial characterization of <i>β</i>‐1,4‐xylosyltransferase from wheat

Abstract

The biosynthesis of arabinoxylan was investigated using microsomal membranes isolated from wheat seedlings. Incubation of the microsomes with UDP‐[ C]‐ d ‐xylose resulted in incorporation of radioactivity into polymeric product. Incorporation reached a maximum at day 3 during development of the seedlings. Treatment of the radiolabeled product with Aspergillus niger xylanase A released about 70% of the radioactivity to a 65% ethanol‐soluble fraction. The released radioactivity was shown to be in the form of xylobiose, xylotriose and xylotetraose, which are the expected hydrolysis products of endo ‐xylanases. The synthesized xylan had an apparent molecular mass larger than 500 kDa.