5.1.3.5 physiological function bifunctional cytosolic UDP-glucose 4-epimerase catalyses the interconversion between UDP-D-xylose and UDP-L-arabinose in plants 702141 5.1.3.5 physiological function the enzyme is involved in the biosynthesis of anti-tumor polysaccharides in Ornithogalum caudatum. Enzyme UXE also plays a key role in carbohydrate partitioning, plant growth and development. UXE is important in the composition of the sugar nucleotide pools 749287