EC 2.4.2.39     
Accepted name: xyloglucan 6-xylosyltransferase
Reaction: Transfers an α-D-xylosyl residue from UDP-D-xylose to a glucose residue in xyloglucan, forming an α-(1→6)-D-xylosyl-D-glucose linkage
Other name(s): uridine diphosphoxylose-xyloglucan 6α-xylosyltransferase; xyloglucan 6-α-D-xylosyltransferase; UDP-D-xylose:xyloglucan 1,6-α-D-xylosyltransferase
Systematic name: UDP-D-xylose:xyloglucan 6-α-D-xylosyltransferase
Comments: In association with EC 2.4.1.168 (xyloglucan 4-glucosyltransferase), this enzyme brings about the synthesis of xyloglucan; concurrent transfers of glucose and xylose are necessary for this synthesis.
References:
1.  Hayashi, T. and Matsuda, K. Biosynthesis of xyloglucan in suspension-cultured soybean cells. Occurrence and some properties of xyloglucan 4-β-D-glucosyltransferase and 6-α-D-xylosyltransferase. J. Biol. Chem. 256 (1981) 11117–11122. [PMID: 6457048]
2.  Hayashi, T. and Matsuda, K. Biosynthesis of xyloglucan in suspension-cultured soybean cells - synthesis of xyloglucan from UDP-glucose and UDP-xylose in the cell-free system. Plant Cell Physiol. 22 (1981) 517–523.
[EC 2.4.2.39 created 1989 as EC 2.4.1.169, transferred 2003 to EC 2.4.2.39]