UDP-D-xylose

While UDP-apiose was being identified, several workers began the purification and characterization of the enzyme(s) in cell-free extracts of L. minor and P. crispum that produce UDP-apiose. il 94,96,97,100-102 It had earlier been inferred that only one enzyme might be necessary to form UPD-apiose and UDP-D-xylose... 

Xylan. Experiments in vivo by several investigators (30) indicated that xylan in plants originated from glucose by a series of reactions first leading to the formation of pentose polysaccharide. UDP-D-xylose has been isolated from plant seedlings and synthesized enzymically from UDP-D-glucose by the following sequence of reactions ... 

Particulate preparations from com shoots readily incorporate 14C-labeled D-xylose from UDP-D-xylose-14C into a polysaccharide in which the D-xylose residues are combined by / -l,4-D-xylosyl bonds (31). It was shown that this polysaccharide, similar to natural plant xylan, contains a small proportion of L-arabinose units which have the furanose configuration. 

Brinkmann T, Weilke C, Kleesiek K. Recognition of acceptor proteins by UDP-d-xylose proteoglycan core protein b-d-xylosyltransferase. J Biol Chem 1997 272 11171-11175. 

D Alessandro, G. and Northcote, D.H., Changes in enzymic activities of UDP-D-glucuronate decarboxylase and UDP-D-xylose 4-epimerase during cell division and xylem differentiation in cultured explants of Jerusalem artichoke, Phytochemistry, 16, 853-859, 1977. 

In contrast to the aldolases, 6-O-phosphono-D-gluconate dehydrogenase45 (E.C. 1.1.1.44) and UDP-D-glucuronate decarboxylase76 (E.C. 4.1.1.b) catalyze decarboxylation with inversion of configuration, giving as products, in water-t, D-eri/ffiro-pentulose-l(S)-t 5-phosphate and UDP-D-xylose-5(S)-t, respectively. 

Burget, E.G., Verma, R., Molho, M., and Reiter, W.-D., 2003, The biosynthesis of L-arabinose in plants Molecular cloning and characterization of a Golgi-localized UDP-D-xylose 4-epimerase encoded by the MUR4 gene of Arabidopsis. Plant Cell 15 523-531. 

Kobayashi, M., Nakagawa, H., Suda, I., Miyagawa, I., and Matoh, T., 2002, Purification and cDNA cloning of UDP-D-glucuronate carboxy-lyase (UDP-D-xylose synthase) from pea seedlings. Plant Cell Physiol. 43 1259-1265. 

UDP-D-xylose, GDP-D-mannose, GDP-L-Fucose, or CMP-D-A-acetylneuraminic acid. Mammalian GTs also use dolichol-diphosphate-GlcNAc2Man9GlC3, dolichol-phosphate-mannose and dolichol-phosphate-glucose (Fig. 2). 

---