N4-{N-acetyl-β-D-glucosaminyl-(1,2)-α-D-mannosyl-(1,3)-[N-acetyl-β-D-glucosaminyl-(1,2)-α-D-mannosyl-(1,6)]-β-D-mannosyl-(1,4)-N-acetyl-β-D-glucosaminyl-(1,4)-N-acetyl-β-D-glucosaminyl}asparagine + UDP-α-D-xylose ↔ N4-{N-acetyl-β-D-glucosaminyl-(1,2)-α-D-mannosyl-(1,3)-[N-acetyl-β-D-glucosaminyl-(1,2)-α-D-mannosyl-(1,6)]-[β-D-xylosyl-(1,2)]-β-D-mannosyl-(1,4)-N-acetyl-β-D-glucosaminyl-(1,4)-N-acetyl-β-D-glucosaminyl}asparagine + UDP