3-O-[N-acetyl-beta-D-glucosaminyl-(1->3)-N-acetyl-alpha-D-galactosaminyl]-L-seryl-[protein] + UDP-N-acetyl-alpha-D-glucosamine = 3-O-[N-acetyl-beta-D-glucosaminyl-(1->3)-[N-acetyl-beta-D-glucosaminyl-(1->6)]-N-acetyl-alpha-D-galactosaminyl]-L-seryl-[protein] + UDP + H(+)
3-o-[n-acetyl-beta-d-glucosaminyl-(1->3)-n-acetyl-alpha-d-galactosaminyl]-l-seryl-[protein] + udp-n-acetyl-alpha-d-glucosamine = 3-o-[n-acetyl-beta-d-glucosaminyl-(1->3)-[n-acetyl-beta-d-glucosaminyl-(1->6)]-n-acetyl-alpha-d-galactosaminyl]-l-seryl-[protein] + udp + h(+)