EC 2.4.2.61     
Accepted name: α-dystroglycan β1,4-xylosyltransferase
Reaction: UDP-α-D-xylose + 3-O-[Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein] = UDP + 3-O-[β-D-Xyl-(1→4)-Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein]
Other name(s): TMEM5 (gene name)
Systematic name: UDP-α-D-xylose:3-O-[Rib-ol-P-Rib-ol-P-3-β-D-GalNAc-(1→3)-β-D-GlcNAc-(1→4)-O-6-P-α-D-Man]-Ser/Thr-[protein] xylosyltransferase
Comments: This eukaryotic enzyme catalyses a step in the biosynthesis of the glycan moiety of the membrane protein α-dystroglycan. It is specific for the second ribitol 5-phosphate in the nascent glycan chain as acceptor.
References:
1.  Vuillaumier-Barrot, S., Bouchet-Seraphin, C., Chelbi, M., Devisme, L., Quentin, S., Gazal, S., Laquerriere, A., Fallet-Bianco, C., Loget, P., Odent, S., Carles, D., Bazin, A., Aziza, J., Clemenson, A., Guimiot, F., Bonniere, M., Monnot, S., Bole-Feysot, C., Bernard, J.P., Loeuillet, L., Gonzales, M., Socha, K., Grandchamp, B., Attie-Bitach, T., Encha-Razavi, F. and Seta, N. Identification of mutations in TMEM5 and ISPD as a cause of severe cobblestone lissencephaly. Am. J. Hum. Genet. 91 (2012) 1135–1143. [PMID: 23217329]
2.  Manya, H., Yamaguchi, Y., Kanagawa, M., Kobayashi, K., Tajiri, M., Akasaka-Manya, K., Kawakami, H., Mizuno, M., Wada, Y., Toda, T. and Endo, T. The muscular dystrophy gene TMEM5 encodes a ribitol β1,4-xylosyltransferase required for the functional glycosylation of dystroglycan. J. Biol. Chem. 291 (2016) 24618–24627. [PMID: 27733679]
[EC 2.4.2.61 created 2018]