Cooperative action of beta-glucan synthetase and UDP-xylose xylosyl transferase of Golgi membranes in the synthesis of xyloglucan-like polysaccharide.

Golgi membranes of pea seedling tissue contain a UDP xylose:polysaccharide xylosyl transferase, the action of which is stimulated by UDP glucose. In the presence of both nucleotide-sugars a heteropolysaccharide containing both xylose and glucose (xyloglucan) is produced. Transfer of xylose and glucose units is presumed to be due to separate enzymes, because their properties differ in a number of respects. Xylosyl units appear to be transferred to a glucan core polysaccharide that is produced from UDP glucose by beta-1,4-glucan synthetase. This, rather than cellulose biosynthesis, is inferred to be the in vivo role of Golgi membrane beta-1,4-glucan synthetase.