An Arabidopsis gene encoding an α-xylosyltransferase involved in xyloglucan biosynthesis

摘要

Microsomal membranes catalyze the formation of xyloglucan from UDP-Glc and UDP-Xyl by cooperative action of α-xylosyltransferase and β-glucan synthase activities. Here we report that etiolated pea microsomes contain an α-xylosyltransferase that catalyzes the transfer of xylose from UDP-[~14C]xylose onto β(1,4)-linked glucan chains. The solubilized enzyme had the capacity to transfer xylosyl residues onto cello-oligosaccharides having 5 or more glucose residues. Analysis of the data from these biochemical assays led to the identification of a group of Arabidopsis genes and the hypoth- esis that one or more members of this group may encode α-xylo- syltransferases involved in xyloglucan biosynthesis.